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Background: Previous estimates of the number of cancers attributable to physical inactivity in the United States have typically focused on only three malignancies (colon, endometrial, and postmenopausal breast cancer). Contemporary epidemiologic evidence suggests that physical inactivity could contribute to up to 15 types of cancer, and a dose-response effect has been demonstrated for 13 of these. This study estimated the number of cancers diagnosed in the United States in 2015 due to physical inactivity for these 13 sites., Methods: Data from the 2005 National Health Interview Survey were used to estimate physical activity prevalence and, with the assumption of a 10-year latency period, 2015 cancer incidence data from the National Program of Cancer Registries and Surveillance, Epidemiology, and End Results Incidence US Cancer Statistics Public Use Database., Results: The potential impact fraction was estimated to be 4.1%, which meant that 30,951 of 761,625 incident cancers at the 13 sites could have been prevented in the United States in 2015 if adults had increased physical activity by one category in 2005 (approximately 7.5 additional metabolic equivalent task hours per week [MET-h/week]). Theoretically, 85,415 of 761,625 incident cancers at the 13 sites (population attributable fraction, 11.2%) could have been prevented if all adults had achieved the highest level of physical activity (>30 MET-h/week)., Conclusions: When estimates are based on updated epidemiologic evidence regarding physical inactivity and cancer risk, substantially more cancers are attributable to physical inactivity than previously reported. A greater focus on physical activity promotion is warranted for cancer control in the United States., (© 2025 The Author(s). Cancer published by Wiley Periodicals LLC on behalf of American Cancer Society. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.)

Background: Physical activity and sedentary behavior are associated with health outcomes. However, evidence may be affected by confounding bias. This study aimed to examine the relationships of physical activity and television (TV) viewing time with all-cause, cardiovascular, and cancer mortality in a cohort of Australian adults, and determine the robustness of these relationships to residual and unmeasured confounding., Methods: Data from 27,317 Melbourne Collaborative Cohort Study participants (mean age = 66) were used. Physical activity was assessed using the International Physical Activity Questionnaire-Short Form and categorized as insufficient, sufficient, or more than sufficient. TV viewing time was categorized as low, moderate, or high. Multivariable Cox regression models were used to evaluate associations of interest. E-values were calculated to assess the strength of unmeasured confounders required to negate the observed results., Results: For highest versus lowest physical activity category, the hazard ratio was 0.67 (95% confidence interval, 0.56-0.81) for all-cause mortality; E-values ranged between 1.79 and 2.44. Results were similar for cardiovascular mortality; however, hazard ratios were lower (0.72; 95% confidence interval, 0.51-1.01) and E-values much smaller (1.00-2.12) for cancer mortality. For highest versus lowest TV viewing time category, the hazard ratio was 1.08 (1.01-1.15) for all-cause mortality; E-values ranged between 1.00 and 1.37. Results were similar for cardiovascular and cancer mortality., Conclusions: Physical activity and TV viewing time were associated with mortality. The robustness to unmeasured/residual confounding was moderate for physical activity (all-cause and cardiovascular mortality), but weaker for physical activity (cancer mortality) and TV viewing time in this study of Australian adults.

Objectives: It was previously estimated that 1814 (1.6 % of incident cancers) were attributable to physical inactivity in Australia in 2010, when only three sites were considered. We estimated the burden of cancer due to physical inactivity in Australia for 13 sites., Design: The population attributable fraction estimated site-specific cancer cases attributable to physical inactivity for 13 cancers. The potential impact fraction was used to estimate cancers that could have been prevented in 2015 if Australian adults had increased their physical activity by a modest amount in 2004-05., Methods: We used 2004-05 national physical activity prevalence data, 2015 national cancer incidence data, and contemporary relative-risk estimates for physical inactivity and cancer. We assumed a 10-year latency period., Results: An estimated 6361 of the cancers observed in 2015 were attributable to physical inactivity, representing 4.8 % of all cancers diagnosed. If Australian adults had increased their physical activity by one category in 2004-05, 2564 cases (1.9 % of all cancers) could have been prevented in 2015., Conclusions: More than three times as many cancers are attributable to physical inactivity than previously reported. Physical activity promotion should be a central component of cancer prevention programmes in Australia., Competing Interests: Declaration of interest statement None., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Background: Sedentary behaviours have been associated with increased risks of some common cancers in epidemiological studies; however, it is unclear if these associations are causal., Methods: We used univariable and multivariable two-sample Mendelian randomisation (MR) to examine potential causal relationships between sedentary behaviours and risks of breast, colorectal and prostate cancer. Genetic variants associated with self-reported leisure television watching and computer use were identified from a recent genome-wide association study (GWAS). Data related to cancer risk were obtained from cancer GWAS consortia. A series of sensitivity analyses were applied to examine the robustness of the results to the presence of confounding., Results: A 1-standard deviation (SD: 1.5 h/day) increment in hours of television watching increased risk of breast cancer (OR per 1-SD: 1.15, 95% confidence interval [CI]: 1.05-1.26) and colorectal cancer (OR per 1-SD: 1.32, 95% CI: 1.16-1.49) while there was little evidence of an association for prostate cancer risk (OR per 1-SD: 0.94, 95% CI: 0.84-1.06). After adjusting for years of education, the effect estimates for television watching were attenuated (breast cancer, OR per 1-SD: 1.08, 95% CI: 0.92-1.27; colorectal cancer, OR per 1-SD: 1.08, 95% CI: 0.90-1.31). Post hoc analyses showed that years of education might have a possible confounding and mediating role in the association between television watching with breast and colorectal cancer. Consistent results were observed for each cancer site according to sex (colorectal cancer), anatomical subsites and cancer subtypes. There was little evidence of associations between genetically predicted computer use and cancer risk., Conclusions: Our univariable analysis identified some positive associations between hours of television watching and risks of breast and colorectal cancer. However, further adjustment for additional lifestyle factors especially years of education attenuated these results. Future studies using objective measures of exposure can provide new insights into the possible role of sedentary behaviour in cancer development., (© 2023 World Health Organization; licensed by John Wiley & Sons Ltd. Cancer Medicine published by John Wiley & Sons Ltd.)

Objectives: Physical inactivity and sedentary behaviour are associated with higher breast cancer risk in observational studies, but ascribing causality is difficult. Mendelian randomisation (MR) assesses causality by simulating randomised trial groups using genotype. We assessed whether lifelong physical activity or sedentary time, assessed using genotype, may be causally associated with breast cancer risk overall, pre/post-menopause, and by case-groups defined by tumour characteristics., Methods: We performed two-sample inverse-variance-weighted MR using individual-level Breast Cancer Association Consortium case-control data from 130 957 European-ancestry women (69 838 invasive cases), and published UK Biobank data (n=91 105-377 234). Genetic instruments were single nucleotide polymorphisms (SNPs) associated in UK Biobank with wrist-worn accelerometer-measured overall physical activity (n snps =5) or sedentary time (n snps =6), or accelerometer-measured (n snps =1) or self-reported (n snps =5) vigorous physical activity., Results: Greater genetically-predicted overall activity was associated with lower breast cancer overall risk (OR=0.59; 95% confidence interval (CI) 0.42 to 0.83 per-standard deviation (SD;~8 milligravities acceleration)) and for most case-groups. Genetically-predicted vigorous activity was associated with lower risk of pre/perimenopausal breast cancer (OR=0.62; 95% CI 0.45 to 0.87,≥3 vs. 0 self-reported days/week), with consistent estimates for most case-groups. Greater genetically-predicted sedentary time was associated with higher hormone-receptor-negative tumour risk (OR=1.77; 95% CI 1.07 to 2.92 per-SD (~7% time spent sedentary)), with elevated estimates for most case-groups. Results were robust to sensitivity analyses examining pleiotropy (including weighted-median-MR, MR-Egger)., Conclusion: Our study provides strong evidence that greater overall physical activity, greater vigorous activity, and lower sedentary time are likely to reduce breast cancer risk. More widespread adoption of active lifestyles may reduce the burden from the most common cancer in women., Competing Interests: Competing interests: MWB conducts research funded by Amgen, Novartis and Pfizer. PAF conducts research funded by Amgen, Novartis and Pfizer. He received honoraria from Roche, Novartis and Pfizer. AWK declares research funding to her institution from Myriad Genetics for an unrelated project (funding dates 2017-2019). SL declares grants and honoraria paid to her institution from Amgen, Novartis, Pfizer, Roche, and, outside the submitted work, grants and/or honoraria paid to her institution from AbbVie, Celgene, Seattle Genetics, PrIME/Medscape, Daiichi-Sankyo, Lilly, Samsung, BMS, Puma, Immunomedics, AstraZeneca, Pierre Fabre, Merck, GlaxoSmithKlein, EirGenix, and Bayer, and personal fees from Chugai; SL also has a patent EP14153692.0 pending. UM declares stock ownership in Abcodia Ltd. RAM has been a consultant for Pharmavite. No other authors have conflicts to declare., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Questions remain about the effect on mortality of physical activity and sedentary behaviour over time. We summarized the evidence from studies that assessed exposure from multiple time points and critiqued the analytic approaches used., Methods: A search was performed on MEDLINE, Embase, Emcare, Scopus and Web of Science up to January 2021 for studies of repeatedly assessed physical activity or sedentary behaviour in relation to all-cause or cause-specific mortality. Relative risks from individual studies were extracted. Each study was assessed for risk of bias from multiple domains., Results: We identified 64 eligible studies (57 on physical activity, 6 on sedentary behaviour, 1 on both). Cox regression with a time-fixed exposure history (n = 45) or time-varying covariates (n = 13) were the most frequently used methods. Only four studies used g-methods, which are designed to adjust for time-varying confounding. Risk of bias arose primarily from inadequate adjustment for time-varying confounders, participant selection, exposure classification and changes from measured exposure. Despite heterogeneity in methods, most studies found that being consistently or increasingly active over adulthood was associated with lower all-cause and cardiovascular-disease mortality compared with being always inactive. Few studies examined physical-activity changes and cancer mortality or effects of sedentary-behaviour changes on mortality outcomes., Conclusions: Accumulating more evidence using longitudinal data while addressing the methodological challenges would provide greater insight into the health effects of initiating or maintaining a more active and less sedentary lifestyle., (© The Author(s) 2021; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association.)

Introduction: Long-term effects of physical activity and television (TV) viewing on mortality have been inferred from observational studies. The associations observed do not allow for inferences about the effects of population interventions and could be subject to bias due to time-varying confounding., Methods: Using data from the Australian Diabetes, Obesity and Lifestyle Study, collected in 1999-2000 (T0), 2004-2005 (T1), and 2011-2012 (T2), we applied the parametric g-formula to estimate cumulative risks of death under hypothetical interventions on physical activity and/or TV viewing determined from self-report while adjusting for time-varying confounding., Results: In the 6377 participants followed up for 13 yr from 2004 to 2005 to death or censoring in 2017, 781 participants died. The observed cumulative risk of death was 12.2%. The most effective hypothetical intervention was to increase weekly physical activity to >300 min (risk ratio (RR), 0.66 (0.46-0.86) compared with a "worst-case" scenario; RR, 0.83 (0.73-0.94) compared with no intervention). Reducing daily TV viewing to <2 h in addition to physical activity interventions did not show added survival benefits. Reducing TV viewing alone was least effective in reducing mortality (RR, 0.85 (0.60-1.10) compared with the worst-case scenario; RR, 1.06 (0.93-1.20) compared with no intervention)., Conclusions: Our findings suggested that sustained interventions to increase physical activity could lower all-cause mortality over a 13-yr period, and there might be limited gain from intervening to reduce TV viewing time in a relatively healthy population., (Copyright © 2020 by the American College of Sports Medicine.)

Background: Prolonged sitting time is a risk factor for chronic disease, yet recent global surveillance is not well described. The aims were to clarify: (i) the countries that have collected country-level data on self-reported sitting time; (ii) the single-item tools used to collect these data; and (iii) the duration of sitting time reported across low- to high-income countries., Methods: Country-level data collected within the last 10 years using single-item self-report were included. The six-stage methodology: (1) reviewing Global Observatory for Physical Activity! Country Cards; (2-4) country-specific searches of PubMed, the Demographic and Health Survey website and Google; (5) analysing the Eurobarometer 88.4; and (6) country-specific searches for World Health Organization STEPwise reports., Results: A total of 7641 records were identified and screened for eligibility. Sixty-two countries (29%) reported sitting time representing 47% of the global adult population. The majority of data were from high-income (61%) and middle income (29%) countries. The tools used were the International Physical Activity Questionnaire (IPAQ; n = 34), a modified IPAQ (n = 1) or the Global Physical Activity Questionnaire (GPAQ; n = 27). The median of mean daily sitting times was 4.7 (IQR: 3.5-5.1) hours across all countries. Higher-income countries recorded a longer duration of sitting time than lower-income countries (4.9 vs 2.7 h)., Conclusions: This study provides an updated collation of countries collecting self-reported sitting time data. The daily sitting time findings should be interpreted cautiously. Current surveillance of sitting time is limited by a lack of coverage. Measures of population sitting time that are valid, feasible and sensitive to change should be embedded within global surveillance systems, to help guide future policy, research and practice., Trial Registration: Not applicable.

Background: High levels of sedentary behavior may negatively affect health outcomes in cancer survivors. A systematic review and meta-analysis was performed to clarify whether postdiagnosis sedentary behavior is related to survival, patient-reported outcomes, and anthropometric outcomes in cancer survivors., Methods: The Ovid MEDLINE, EMBASE, CINAHL (The Cumulative Index to Nursing and Allied Health Literature), and SPORTDiscus databases were searched from study inception to June 2019. Studies of adults who had been diagnosed with cancer that examined the association between sedentary behavior and mortality, patient-reported outcomes (eg, fatigue, depression), or anthropometric outcomes (eg, body mass index, waist circumference) were eligible for inclusion. Meta-analyses were performed to estimate hazard ratios for the highest compared with the lowest levels of sedentary behavior for all-cause and colorectal cancer-specific mortality outcomes. The ROBINS-E (Risk of Bias in Nonrandomized Studies-of Exposures tool) and the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) system were used to assess the risk of bias and the strength of evidence, respectively., Results: Thirty-three eligible publications from a total of 3569 identified articles were included in the review. A higher level of postdiagnosis sedentary behavior was associated with an increased risk of all-cause mortality (hazard ratio, 1.22; 95% CI, 1.06-1.41; heterogeneity [I 2 statistic], 33.8%) as well as colorectal cancer-specific mortality (hazard ratio, 1.53; 95% CI, 1.14-2.06; I 2 , 0%). No clear or consistent associations between sedentary behavior and patient-reported or anthropometric outcomes were identified. The risk of bias in individual studies ranged from moderate to serious, and the strength of evidence ranged from very low to low., Conclusions: Although avoiding high levels of sedentary behavior after a cancer diagnosis may improve survival, further research is required to help clarify whether the association is causal., (© 2019 American Cancer Society.)

Background: Recent updates to physical activity guidelines highlight the importance of reducing sedentary time. However, at present, only general recommendations are possible (ie, "Sit less, move more"). There remains a need to investigate the strength, temporality, specificity, and dose-response nature of sedentary behavior associations with chronic disease, along with potential underlying mechanisms., Methods: Stemming from a recent research workshop organized by the Sedentary Behavior Council themed "Sedentary behaviour mechanisms-biological and behavioural pathways linking sitting to adverse health outcomes," this paper (1) discusses existing challenges and scientific discussions within this advancing area of science, (2) highlights and discusses emerging areas of interest, and (3) points to potential future directions., Results: A brief knowledge update is provided, reflecting upon current and evolving thinking/discussions, and the rapid accumulation of new evidence linking sedentary behavior to chronic disease. Research "action points" are made at the end of each section-spanning from measurement systems and analytic methods, genetic epidemiology, causal mediation, and experimental studies to biological and behavioral determinants and mechanisms., Conclusion: A better understanding of whether and how sedentary behavior is causally related to chronic disease will allow for more meaningful conclusions in the future and assist in refining clinical and public health policies/recommendations.

Background: Physical activity has beneficial effects on the health of cancer survivors. We aimed to investigate accelerometer-assessed physical activity and sedentary time in cancer survivors, and describe activity profiles. Additionally, we identify demographic and clinical correlates of physical activity, sedentary time and activity profiles., Methods: Accelerometer, questionnaire and clinical data from eight studies conducted in four countries (n = 1447) were pooled. We calculated sedentary time and time spent in physical activity at various intensities using Freedson cut-points. We used latent profile analysis to identify activity profiles, and multilevel linear regression analyses to identify demographic and clinical variables associated with accelerometer-assessed moderate to vigorous physical activity (MVPA), sedentary time, the highly active and highly sedentary profile, adjusting for confounders identified using a directed acyclic graph., Results: Participants spent on average 26 min (3%) in MVPA and 568 min (66%) sedentary per day. We identified six activity profiles. Older participants, smokers and participants with obesity had significantly lower MVPA and higher sedentary time. Furthermore, men had significantly higher MVPA and sedentary time than women and participants who reported less fatigue had higher MVPA time. The highly active profile included survivors with high education level and normal body mass index. Haematological cancer survivors were less likely to have a highly active profile compared to breast cancer survivors. The highly sedentary profile included older participants, males, participants who were not married, obese, smokers, and those < 12 months after diagnosis., Conclusions: Cancer survivors engage in few minutes of MVPA and spend a large proportion of their day sedentary. Correlates of MVPA, sedentary time and activity profiles can be used to identify cancer survivors at risk for a sedentary and inactive lifestyle.

Background: The benefits of an active lifestyle after a breast cancer diagnosis are well recognized, but the majority of survivors are insufficiently active. The ACTIVATE Trial examined the efficacy of an intervention (use of the Garmin Vivofit 2 activity monitor coupled with a behavioral feedback and goal-setting session and 5 telephone-delivered health coaching sessions) to increase moderate to vigorous physical activity (MVPA) and reduce sedentary behavior in breast cancer survivors., Methods: This randomized controlled trial recruited 83 inactive, postmenopausal women diagnosed with stage I-III breast cancer who had completed primary treatment. Participants were randomly assigned to the intervention group or to the control group, and the intervention was delivered over a 12-week period. MVPA and sedentary behavior were measured with Actigraph and activPAL accelerometers at baseline (T1) and at the end of the intervention (T2)., Results: Retention in the trial was high, with 80 (96%) of participants completing T2 data collection. At T2, there was a significant between-group difference in MVPA (69 min/wk; 95% CI = 22-116) favoring the intervention group. The trial resulted in a statistically significant decrease in both total sitting time and prolonged bouts (≥20 min) of sitting, with between-group reductions of 37 min/d (95% CI = -72 to -2) and 42 min/d (95% CI = -83 to -2), respectively, favoring the intervention group., Conclusion: Results from the ACTIVATE Trial suggest that the use of wearable technology presents an inexpensive and scalable opportunity to facilitate more active lifestyles for cancer survivors. Whether or not such wearable technology-based interventions can create sustainable behavioral change should be the subject of future research., (© 2019 American Cancer Society.)

Introduction: Physical activity may affect health via DNA methylation. The epigenetic influences of sedentary behaviors such as television viewing are unknown. We performed a genomewide study of DNA methylation in peripheral blood in relation to physical activity and television viewing time., Methods: DNA methylation was measured using the Illumina Infinium HumanMethylation450K BeadChip array in blood samples collected at baseline (N = 5513) and follow-up (N = 1249) from participants in the Melbourne Collaborative Cohort Study. At baseline, times per week of leisure-time physical activity were self-reported. At follow-up, the International Physical Activity Questionnaire was used to assess MET-hours per week of total and leisure-time physical activity and hours per day of television viewing time. Linear mixed models were used to assess associations between physical activity and television viewing measures and DNA methylation at individual CpG sites, adjusted for potential confounders and batch effects., Results: At follow-up, total physical activity was associated with DNA methylation at cg10266336 (P = 6.0 × 10), annotated to the SAA2 gene. Weaker evidence of associations (P < 1.0 × 10) were observed for an additional 14 CpG sites with total physical activity, for 7 CpG sites with leisure-time physical activity, and for 9 CpG sites with television viewing time. Changes in leisure-time physical activity between baseline and follow-up were associated with methylation changes (P < 0.05) at four of the seven CpG sites with weaker evidence of cross-sectional associations with leisure-time physical activity., Conclusion: Physical activity and television viewing may be associated with blood DNA methylation, a potential pathway to chronic disease development. Further research using accelerometer data and larger sample sizes is warranted.

Background: High volumes of sitting time are associated with an elevated risk of type 2 diabetes and cardiovascular disease, and with adverse cardiometabolic risk profiles. However, previous studies have predominately evaluated only total sitting or television (TV) viewing time, limiting inferences about the specific cardiometabolic health impacts of sitting accumulated in different contexts. We examined associations of sitting time in four contexts with cardiometabolic risk biomarkers in Australian adults., Methods: Participants (n = 3429; mean ± SD age 58 ± 10 years) were adults without clinically diagnosed diabetes or cardiovascular disease from the 2011-2012 Australian Diabetes, Obesity and Lifestyle (AusDiab) study. Multiple linear regressions examined associations of self-reported context-specific sitting time (occupational, transportation, TV-viewing and leisure-time computer use) with a clustered cardiometabolic risk score (CMR) and with individual cardiometabolic risk biomarkers (waist circumference, BMI, resting blood pressure, triglycerides, HDL- and LDL-cholesterol, and fasting and 2-h post-load plasma glucose)., Results: Higher CMR was significantly associated with greater TV-viewing and computer sitting time (b [95%CI] = 0.07 [0.04, 0.09] and 0.06 [0.03, 0.09]), and tended to be associated with higher occupational and transport sitting time (0.01 [- 0.01, 0.03] and 0.03 [- 0.00, 0.06]), after adjustment for potential confounders. Furthermore, keeping total sitting time constant, accruing sitting via TV-viewing and computer use was associated with significantly higher CMR (0.05 [0.02, 0.08] and 0.04 [0.01, 0.06]), accruing sitting in an occupational context was associated with significantly lower CMR (- 0.03 [- 0.05, - 0.01]), while no significant association was seen for transport sitting (0.00 [- 0.03, 0.04]). Results varied somewhat between the respective biomarkers; however, higher sitting time in each domain tended to be associated detrimentally with individual biomarkers except for fasting glucose (non-significant associations) and systolic blood pressure (a beneficial association was observed). Overall, associations were stronger for TV-viewing and computer use, and weaker for occupational sitting., Conclusions: Higher context-specific sitting times tended to be detrimentally associated, albeit modestly, with CMR and several cardiometabolic risk biomarkers. There was some evidence suggesting that the context in which people sit is relevant above and beyond total sitting time. Methodological issues notwithstanding, these findings may assist in identifying priorities for sitting-reduction initiatives, in order to achieve optimal cardiometabolic health benefits.

Sitting has frequently been equated with smoking, with some sources even suggesting that smoking is safer than sitting. This commentary highlights how sitting and smoking are not comparable. The most recent meta-analysis of sedentary behavior and health outcomes reported a hazard ratio of 1.22 (95% confidence interval [CI] = 1.09, 1.41) for all-cause mortality. The relative risk (RR) of death from all causes among current smokers, compared with those who have never smoked, is 2.80 (95% CI = 2.72, 2.88) for men and 2.76 for women (95% CI = 2.69, 2.84). The risk is substantially higher for heavy smokers (> 40 cigarettes per day: RR = 4.08 [95% CI = 3.68, 4.52] for men, and 4.41 [95% CI = 3.70, 5.25] for women). These estimates correspond to absolute risk differences of more than 2000 excess deaths from any cause per 100 000 persons per year among the heaviest smokers compared with never smokers, versus 190 excess deaths per 100 000 persons per year when comparing people with the highest volume of sitting with the lowest. Conflicting or distorted information about health risks related to behavioral choices and environmental exposures can lead to confusion and public doubt with respect to health recommendations.

Background: In the cancer survivorship context, physical activity and sedentary behavior have been measured using different methods., Purpose: To conduct a narrative review of published research in cancer survivor populations to summarize the quality and identify gaps in reporting on accelerometer data collection, data processing, and outcome measures in cancer survivors., Methods: An initial PubMed® search of articles published in English was conducted in January 2017, and a final search was conducted in May 2017. Variables extracted included study characteristics, methods for accelerometry data collection (e.g., device used), data processing (e.g., cut points used), and data reporting (e.g., time spent in different activity intensities)., Results: A total of 46 articles were eligible for inclusion in the review. The majority of studies (34 of 46) targeted a single cancer group and 18 of these 34 studies were in survivors of breast cancer. Half (54%) of the studies used an ActiGraph® accelerometer. Methods of accelerometer data processing varied across studies. Definitions of non-wear time, vectors used during processing, and filters applied during processing were reported by 51%, 60%, and 8% of studies, respectively. Most studies reported moderate and vigorous physical activity (78%), 50% reported sedentary time, and 43% reported light-intensity activity. Cut points to categorize these activities varied between studies., Conclusions: This narrative review highlights inconsistency in the methods used to collect, process, and report accelerometry data across cancer survivor studies. Accelerometry has potential to add detailed knowledge of the levels and patterns of physical activities and sedentary behaviors across the cancer spectrum. Recommendations are made to improve data processing and reporting methods to maximize the scientific validity of future accelerometer research in this field.

Background: Physical activity is associated with reduced risk of colorectal cancer, but most epidemiological studies have focused on occupational and recreational physical activity. The evidence for other domains of activity, and for sedentary behaviour, is limited., Methods: Medline, Embase and Web of Science were searched from inception to December 2015 for studies examining domain-specific physical activity or sedentary behaviour and the risk of colon and/or rectal cancer. We extracted maximally adjusted relative risks (RRs) except when RRs not adjusted for body mass index, were also presented. We used random-effects meta-analysis to compute pooled RRs comparing the highest versus the lowest level of exposure. We used meta-regression to assess sources of heterogeneity in estimates., Results: We identified 17 cohort and 21 case-control studies, of which 17 had occupational data, 23 had recreational data, three each had data on transport and household physical activity domains, and 6 studies had data on occupational sedentary behaviour. The pooled relative risks (RRs) for colon cancer were 0.74 (95% confidence interval (CI): 0.67, 0.82) for occupational activity, 0.80 (95% CI: 0.71, 0.89) for recreational activity, 0.66 (95% CI: 0.45, 0.98) for transport-related physical activity, 0.85 (95% CI: 0.71, 1.02) for household physical activity, and 1.44 (95% CI: 1.28, 1.62) for occupational sedentary behaviour. For rectal cancer, the pooled RRs were 0.88 (95% CI: 0.79, 0.98) for occupational activity, 0.87 (95% CI: 0.75, 1.01) for recreational activity, 0.88 (95% CI: 0.70, 1.12) for transport-related physical activity, 1.01 (95% CI: 0.80, 1.27) for household physical activity, and 1.02 (95% CI: 0.82, 1.28) for occupational sedentary behaviour., Conclusions: In addition to increasing occupational and recreational physical activity, promoting physical activity during transport and reducing sedentary behaviour in the workplace may also be useful colorectal cancer prevention strategies., (© The Author 2017; all rights reserved. Published by Oxford University Press on behalf of the International Epidemiological Association)

The purpose of this study was to examine potential effects of reallocating time between sleep, sedentary and active behaviours on fatigue symptoms and quality of life in a sample of non-Hodgkin lymphoma survivors. Non-Hodgkin lymphoma survivors identified from the Western Australian Cancer Registry (N = 149) (response rate = 36%; median age = 64 years) wore an Actigraph® GT3X+ accelerometer for 7 days and completed the Fatigue Scale, the Functional Assessment of Cancer Therapy-General and the Pittsburgh Sleep Quality Index. We used isotemporal substitution methods in linear regression models to examine the potential effects of reallocating time between sleep, sedentary and activity behaviours on fatigue and quality of life. Data collection was conducted in Western Australia in 2013. Significant differences were observed for fatigue symptoms when 30 min per day of bouted moderate-to-vigorous physical activity (10 min) was reallocated from 30 min per day of sleep (5.7 points, 95% CI = 1.8, 9.7), sedentary time bouts (20 min) (5.7 points, 95% CI = 1.6, 9.7), sedentary time non-bouts (5.1 points, 95% CI = 1.0, 9.3) or light intensity activity (5.5 points, 95% CI = 1.5, 9.5). Isotemporal substitution effects of reallocating sedentary time, sleep and light physical activity with bouted physical activity was significantly associated with fatigue, but not quality of life. Findings from the present study may aid in the development and delivery of health behaviour interventions that are more likely to influence the health outcome of interest.

Excessive sitting time and smoking are pro-inflammatory lifestyle factors that are associated with both cancer and cardiovascular disease (CVD) mortality. However, their joint associations have not been investigated. We examined the associations of television (TV) viewing time with cancer and CVD mortality, according to smoking status, among 7,498 non-smokers (34% ex-smokers) and 1,409 current-smokers in the Australian Diabetes, Obesity and Lifestyle Study. During 117,506 person-years (median 13.6 years) of follow-up, there were 346 cancer and 209 CVD-related deaths. Including an interaction between TV time and smoking status in the model significantly improved the goodness of fit for cancer (p = 0.01) but not CVD mortality (p = 0.053). In the multivariate-adjusted model, every additional hr/d of TV time was associated with increased risk of cancer-related (HR 1.23; 95% CI 1.08-1.40), but not CVD-related mortality (HR 1.16; 95% CI 0.97-1.38) in current-smokers. Elevated multivariate-adjusted cancer mortality HRs were observed for current-smokers watching 2 to <4 hr/d (HR 1.45; 95% CI 0.78-2.71) and ≥4 hr/d (HR 2.26; 95% CI 1.10-4.64), compared to those watching <2 hr/d. Current-smokers watching 2 to <4 hr/d (HR 1.07; 95% CI 0.45-2.53) and ≥4 hr/d (HR 1.92; 95% CI 0.76-4.84) did not have a significantly higher risk of CVD mortality, compared to <2 hr/d. No associations were observed for non-smokers. These findings show an association of TV, a common sedentary behavior, with cancer mortality in current-smokers. The association with CVD mortality was less clear. Further exploration in larger data sets is warranted. Limiting TV viewing time may be of benefit in reducing cancer mortality risk in current-smokers., (© 2016 UICC.)

Background: The Stand Up Victoria multi-component intervention successfully reduced workplace sitting time in both the short (three months) and long (12 months) term. To further understand how this intervention worked, we aimed to assess the impact of the intervention on four social-cognitive constructs, and examined whether these constructs mediated intervention effects on workplace sitting time at 3 and 12 months post-baseline., Methods: Two hundred and thirty one office-based workers (14 worksites, single government employer) were randomised to intervention or control conditions by worksite. The intervention comprised organisational, environmental, and individual level elements. Participant characteristics and social-cognitive constructs (perceived behavioural control, barrier self-efficacy, perceived organisational norms and knowledge) were measured through a self-administered online survey at baseline, 3 months and 12 months. Workplace sitting time (min/8 h day) was measured with the activPAL3 device. Single multi-level mediation models were performed for each construct at both time points., Results: There were significant intervention effects at 3 months on perceived behavioural control, barrier self-efficacy and perceived organisational norms. Effects on perceived organisational norms were not significant at 12 months. Perceived behavioural control significantly mediated intervention effects at 3 months, accounting for a small portion of the total effect (indirect effect: -8.6 min/8 h day, 95% CI: -18.5, -3.6 min; 7.5% of total effect). At 12 months, barrier self-efficacy significantly mediated the intervention effects on workplace sitting time (indirect effect: -10.3 min/8 h day, 95% CI: -27.3, -2.2; 13.9% of total effect). No significant effects were observed for knowledge at either time point., Conclusions: Strategies that aim to increase workers' perceived control and self-efficacy over their sitting time may be helpful components of sedentary behaviour interventions in the workplace. However, social-cognitive factors only partially explain variation in workplace sitting reduction. Understanding the importance of other levels of influence (particularly interpersonal and environmental) for initiating and maintaining workplace sedentary behaviour change will be informative for intervention development and refinement., Trial Registration: This study was prospectively registered with the Australian New Zealand Clinical Trials register ( ACTRN12611000742976 ) on 15 July 2011.

Objective: To assess differences in accelerometer-assessed moderate- to vigorous-intensity physical activity (MVPA), light-intensity physical activity, and sedentary time between cancer survivors and adults without cancer., Patients and Methods: Accelerometer data collected from 241 breast cancer survivors (ACCEL-Breast study, 2013) and 171 colon cancer survivors (ACCEL-Colon study, 2012-2013) were pooled with data collected from adults without cancer (Australian Diabetes, Obesity and Lifestyle accelerometer substudy, 2011-2012). Linear regression was used to estimate differences in physical activity and sedentary behavior levels between cancer survivors and adults without cancer, adjusted for potential confounding factors., Results: The mean MVPA was significantly higher among breast cancer survivors than among females who had not had cancer (29 vs 22 min/d; P<.001). Colon cancer survivors had significantly lower levels of light activity than did adults without cancer (311 vs 338 min/d; P<.001), more sedentary time (532 vs 507 min/d; P=.003), and more prolonged sedentary time (210 vs 184 min/d; P=.002)., Conclusion: Contrary to findings from previous research (based on self-reported physical activity), cancer survivors engaged in more (breast) or equivalent (colon) MVPA compared with adults without cancer. Differences between colon cancer survivors and adults without cancer for light activity and sedentary behavior highlight the importance of considering the full activity spectrum in the context of cancer control., (Copyright © 2017 Mayo Foundation for Medical Education and Research. Published by Elsevier Inc. All rights reserved.)

Objectives: Few studies have measured the physical activity levels of non-Hodgkin lymphoma (NHL) survivors, and no previous studies have measured sedentary behavior levels in this population. This study used accelerometers to measure the physical activity and sedentary time levels of NHL survivors and examined the demographic, behavioral, and medical correlates of these behaviors., Methods: A total of 156 NHL survivors (mean age = 64 years) completed a questionnaire and wore an accelerometer for seven consecutive days during waking hours. Descriptive statistics were used to describe physical activity and sedentary time levels, and linear regression was used to investigate correlates of these behaviors., Results: Participants averaged 8.6 h of sedentary time per day (60% of their accelerometer wear time), 5.3 h of light-intensity physical activity (37%), and 30 min of moderate-intensity physical activity (3%). Only 12% of the participants accrued the duration of moderate-vigorous physical activity recommended by physical activity guidelines (30 min accrued in bouts of at least 10 min). Female participants, older participants, smokers, and participants with larger waist circumference had lower levels of moderate-to-vigorous intensity physical activity. Smokers and participants with larger waist circumference also had higher sedentary time levels., Conclusion: The NHL survivors in this study spent the majority of their waking hours sedentary, and few met physical activity guidelines. The results of this study emphasize the need for more research exploring the health consequences of sedentary behavior and physical inactivity in NHL survivors. Copyright © 2015 John Wiley & Sons, Ltd., (Copyright © 2015 John Wiley & Sons, Ltd.)

Background: Moderate-to-vigorous intensity physical activity (MVPA) is inversely associated with waist circumference and body mass index (BMI) among breast cancer survivors. Limited research has focused on behaviors that account for larger portions of the day [sleep, sedentary time, and light-intensity physical activity (LPA)]. We investigated the interdependent associations of self-reported sleep, objectively assessed prolonged and short bouts of sedentary time, total LPA, and total MVPA with waist circumference and BMI., Methods: A cross-sectional sample of breast cancer survivors (N = 256, mean age = 60 years; mean time since diagnosis = 3 years) wore an Actigraph GT3X+ accelerometer during waking hours for 7 days. Participants completed the Pittsburgh Sleep Quality Index and self-reported their waist circumference, height, and weight. An isotemporal substitution approach was used in linear regression models to explore the associations of reallocating time to sleep, sedentary and active behaviors on waist circumference, and BMI, after adjusting for potential confounders., Results: Reallocating 30 minutes to MVPA was significantly associated with lower waist circumference when allocated from sleep (-2.50 cm), prolonged sedentary time (-2.51 cm), or LPA (-2.71 cm). Reallocating 30 minutes of prolonged sedentary time to nonprolonged sedentary time was significantly associated with lower waist circumference (-0.94 cm). Similar results were observed for BMI., Conclusions: Reallocating 30 minutes to MVPA was associated with significantly lower waist circumference and BMI, as was reallocating 30 minutes of prolonged sedentary time to 30 minutes of nonprolonged sedentary time., Impact: Increasing MVPA levels and decreasing time spent in prolonged, unbroken sedentary bouts may be avenues for improving body composition in this population. Cancer Epidemiol Biomarkers Prev; 26(2); 254-60. ©2016 AACR., Competing Interests: None to declare, (©2016 American Association for Cancer Research.)

Purpose: Physical activity (PA) and sedentary behavior may influence the physical and mental health of breast cancer survivors; however, few studies have objectively measured these behaviors in this population. We used accelerometers to measure the PA and sedentary time levels of breast cancer survivors and examined the demographic, behavioral, and medical correlates of these behaviors using two complementary approaches., Methods: A total of 259 breast cancer survivors wore an accelerometer for 7 days during waking hours and completed a questionnaire. We used linear regression and classification trees to investigate correlates of PA and sedentary time., Results: The breast cancer survivors in this study (mean age = 61 years, mean time since diagnosis = 3 years) were sedentary for a daily average of 8.2 h, in light-intensity PA for 5.8 h and in moderate-to-vigorous intensity PA (MVPA) for 32 min, with 16 % meeting PA guidelines. Participants with high comorbidity were the least likely to be meeting guidelines (0 %), while a subgroup of participants with no/low comorbidity, a university degree, and higher levels of pre-diagnosis MVPA were the most likely to be meeting guidelines (47 %). Older participants (70+ years) were the most likely to have sedentary time levels at least twice as high as activity levels, while participants who were younger than 70 years and not in the lowest category of pre-diagnosis MVPA were the least likely., Conclusions: Interventions to facilitate physical activity and reduce sedentary time among breast cancer survivors should consider comorbidity status and previous PA experience.

Objective: We examined the correlates of sitting time in a population-based sample of older adults., Methods: Adults >55 years of age (N = 1296; N = 515 employed; N = 781 unemployed) self-reported measures of demographic and health-related variables, and a measure of sitting time (ie, SIT-Q)., Results: Employed total sitting time (min/day) was positively associated with home Internet access (B = 71.2, 95% CI, 8.9 to 133.4, p = .025), body mass index (BMI) (kg/m(2); B = 7.0, 95% CI, 2.1 - 11.9, p = .005), and negatively associated with physical health (B = -2.3; 95% CI, -4.9 to 0.3, p = .013). Unemployed total sitting time was negatively associated with age (B per year = -3.0, 95% CI, -4.9 to -1.1, p = .002), and being male (B = -54.0, 95% CI, -86 .7 to -21.3, p = .001). Unemployed total sitting time was positively associated with Internet access (B = 54.1, 95% CI, 17.7 to 90.4, p = .004) and BMI (B = 4.1, 95% CI, .94 to 7.3, p = .011)., Conclusions: Older adults reported low levels of sitting time. Different correlates emerged for the employed and unemployed samples across sitting domains.

Background: Understanding of the physical activity and sedentary behavior of cancer survivors is limited by reliance on self-reported data. Here, we report the correlates, and patterns of accumulation, of physical activity (light, and moderate-vigorous; MVPA) and sedentary behavior, in colon cancer survivors, using accelerometer-based assessments., Methods: Colon cancer survivors from Alberta, Canada (n = 92), and Western Australia (n = 93) (overall response rate = 21 %) wore an Actigraph(®) GT3X+ accelerometer for seven consecutive days and completed a questionnaire in 2012-2013. Accelerometer data (60 s epochs) were summarized using Freedson activity cutpoints and were adjusted for wear time. Linear regression analyses, conducted 2014-2015, examined correlates for different intensities of activity., Results: Younger age, being employed, higher family income, and lower BMI were significantly correlated with MVPA, while gender, educational attainment, and BMI were correlated with light-intensity physical activity. Gender, comorbidities, and BMI were correlated with sedentary time. MVPA did not vary by day of the week, whereas the remaining time (as a sedentary/light ratio) showed significant variation, with Saturdays being less sedentary than average [corrected]. When considering time of day, we found that evenings were when the likelihood of both MVPA and sedentary time was highest., Conclusions: The low level of MVPA and high volume of sedentary time demonstrated by these objective data highlight the need for intervention in colon cancer survivors. The correlates and accumulation patterns described by this study may better inform interventions and translational research designed to increase physical activity and reduce sedentary behavior in colon cancer survivors.

Background: Sitting time questionnaires have largely been validated in small convenience samples. The validity of this multi-context sitting questionnaire against an accurate measure of sitting time is reported in a large demographically diverse sample allowing assessment of validity in varied demographic subgroups., Methods: A subgroup of participants of the third wave of the Australian Diabetes, Obesity, and Lifestyle (AusDiab3) study wore activPAL3™ monitors (7 days, 24 hours/day protocol) and reported their sitting time for work, travel, television viewing, leisure computer use and "other" purposes, on weekdays and weekend days (n = 700, age 36-89 years, 45% men). Correlations (Pearson's r; Spearman's ρ) of the self-report measures (the composite total, contextual measures and items) with monitor-assessed sitting time were assessed in the whole sample and separately in socio-demographic subgroups. Agreement was assessed using Bland-Altman plots., Results: The composite total had a correlation with monitor-assessed sitting time of r = 0.46 (95% confidence interval [CI]: 0.40, 0.52); this correlation did not vary significantly between demographic subgroups (all >0.4). The contextual measure most strongly correlated with monitor-assessed sitting time was work (ρ = 0.25, 95 % CI: 0.17, 0.31), followed by television viewing (ρ = 0.16, 95 % CI: 0.09, 0.24). Agreement of the composite total with monitored sitting time was poor, with a positive bias (B = 0.53, SE 0.04, p < 0.001) and wide limits of agreement (±4.32 h)., Conclusions: This multi-context questionnaire provides a total sitting time measure that ranks participants well for the purposes of assessing health associations but has limited accuracy relative to activPAL-assessed sitting time. Findings did not differ in demographic subgroups.

Background: Sedentary behavior has been proposed as a risk factor for obesity that is distinct from physical inactivity. This study aimed to examine the association between occupational sedentary behavior and obesity, and to determine if this association is independent of leisure-time physical activity (LTPA)., Methods: Fully employed participants enrolled between 2001 and 2008 to Alberta's Tomorrow Project, a prospective cohort study in Alberta, Canada, were studied (n = 12,409). Associations between occupational sedentary behavior and waist circumference (WC), waist-to-hip ratio (WHR), and body mass index (BMI) were examined using multiple binary and multinomial logistic regressions., Results: In men, a positive association was observed between daily occupational sedentary hours and WC, WHR, BMI, and with high risk profiles that incorporated both BMI and WC (P < .01). Controlling for vigorous-intensity LTPA in all models strengthened associations between sedentary behavior and measures of obesity. In contrast, inverse associations were observed for occupational sedentary hours and WHR for women (P < .05)., Conclusions: In fully employed men, occupational sedentary behavior was positively associated with obesity risk that was not attenuated by physical activity. In women, an increase in obesity risk was not observed with sedentary behavior. Gender differences in the health effects of sedentary behavior require further study.

Background: Recent evidence links sedentary behaviour (or too much sitting) with poorer health outcomes; many adults accumulate the majority of their daily sitting time through occupational sitting and TV viewing. To further the development and targeting of evidence-based strategies there is a need for identification of the factors associated with higher levels of these behaviours. This study examined socio-demographic and health-related correlates of occupational sitting and of combined high levels of occupational sitting/TV viewing time amongst working adults., Methods: Participants were attendees of the third wave (2011/12) of the Australian Diabetes, Obesity and Lifestyle (AusDiab) study who worked full-time (≥35 h/week; n = 1,235; 38 % women; mean ± SD age 53 ± 7 years). Logistic and multinomial logistic regression analyses were conducted (separately for women and men) to assess cross-sectional associations of self-reported occupational sitting time (categorised as high/low based on the median) and also the combination of occupational sitting time/TV viewing time (high/low for each outcome), with a number of potential socio-demographic and health-related correlates., Results: Higher levels of occupational sitting (>6 h/day) were associated with higher household income for both genders. Lower levels of occupational sitting were associated with being older (women only); and, for men only, having a blue collar occupation, having a technical/vocational educational attainment, and undertaking more leisure-time physical activity (LTPA). Attributes associated with high levels of both occupational sitting and TV viewing time included white collar occupation (men only), lower levels of LTPA (both genders), higher BMI (men), and higher energy consumption (women)., Conclusions: Higher household income (both genders) and professional/managerial occupations (men only) were correlates of high occupational sitting time, relative to low occupational sitting time, while health-related factors (lower LTPA, higher BMI - men, and higher energy consumption - women) were associated with high levels of both occupational sitting and TV viewing time, relative to low occupational sitting and low TV viewing time. These findings suggest possible high-risk groups that may benefit from targeted interventions. Further research is needed on potentially modifiable environmental and social correlates of occupational sitting time, in order to inform workplace initiatives.

Purpose: Research conducted on the general population indicates self-reported measures of physical activity and sedentary behaviour are inaccurate when compared with objective measures; however, it is not clear if this also applies to cancer survivors. In this study, we compared accelerometer-based and self-reported measures of moderate- to vigorous-intensity physical activity (MVPA) and sedentary time among colon cancer survivors., Methods: A total of 176 colon cancer survivors, recruited from the Western Australia and Alberta cancer registries, wore an Actigraph GT3X+ accelerometer for 7 days and completed self-reported questions about recent MVPA (Godin Leisure-Time Exercise Questionnaire) and usual sedentary time (Marshall Domain-Specific Sitting Questionnaire). Accelerometer data were processed using 60-s epochs and summarized using Freedson's cut points. Spearman's rho and intraclass correlation coefficients (ICCs) were used to assess correlation and agreement for daily MVPA and sedentary time estimates from the two methods., Results: Total mean minutes per day spent in MVPA was 12 min based on accelerometer data and 26 min based on self-reported data (P Difference  < 0.01). Correlation between the methods was fair (rho = 0.51); however, agreement was poor (ICC = 0.33). Mean daily time spent sedentary was similar in both methods (∼8.5 h); however, both correlation and agreement were poor (rho = 0.19, ICC = 0.16)., Conclusions: We found fair correlation but poor agreement between the self-reported and accelerometer-based assessments of MVPA used in this study. For sedentary time, both correlation and agreement between the two methods were poor. Studies of colon cancer survivors using these self-report measures are likely to have a considerable amount of exposure misclassification.

Objective: To examine associations of accelerometer-assessed sedentary time and self-reported screen time with sleep outcomes., Methods: Cross-sectional study of 1674 adults from the 2005-2006 US National Health and Nutrition Examination Survey. Accelerometers were used to assess sedentary time. Screen time and sleep metrics were assessed via self-report., Results: Accelerometer-assessed sedentary time was not associated with sleep outcomes. Compared to participants with the least screen time (<2h/ day), participants with the most screen time (>6h/day) were more likely to report trouble falling asleep (OR = 2.78, 95% CI: 1.21, 6.40) and wake during the night (OR = 2.55, 95% CI: 1.17, 5.52)., Conclusions: With respect to sleep outcomes, context-specific sedentary behaviors may be more important than overall sedentary time.

Objective: Television (TV) viewing, a common leisure-time sedentary behaviour, is associated adversely with cardio-metabolic health, fatigue, depression and mental health. However, associations of TV viewing time with health-related quality of life attributes are less well understood. We examined associations of TV viewing time with physical well-being, mental well-being and vitality in a large population-based sample of Australian adults., Method: The study sample comprised 4,483 men and 5,424 women (mean age 51±14years) from the Australian Diabetes, Obesity and Lifestyle study (1999-2000). Multiple linear regressions examined associations of TV viewing time (h/day) with the SF-36v1 physical and mental health component summary scores and the vitality sub-score, adjusting for leisure-time physical activity and waist circumference., Results: Each 1-h/day increment in TV viewing time was associated with lower physical (-0.56 [95% CI: -0.77, -0.34]) and mental (-0.41 [-0.70, -0.12]) component summary scores and vitality (-0.51 [-0.81, -0.21]). Associations remained significant after adjustment for leisure-time physical activity and waist circumference. There was a gender interaction for the association of TV viewing time with vitality (significant in men only)., Conclusions: TV viewing time is associated adversely with physical well-being, mental well-being and vitality. Further studies are required to better understand potential causal relationships and variations by gender and leisure-time physical activity., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Purpose: Sedentary behavior has been previously shown, in a cross-sectional study, to have deleterious associations with biomarkers of postmenopausal breast cancer risk. We examined the associations of change in sedentary behavior [daily television (TV) viewing time, h/day] over a 5-year period with putative markers of postmenopausal breast cancer risk., Methods: The analytic cohort consisted of 1,001 postmenopausal women from the Australian Diabetes, Obesity and Lifestyle (AusDiab) study (1999-2005). Multivariate linear regression models were used to examine associations of change in TV viewing time with biomarkers of the following risk mechanisms: adiposity (body mass index [BMI], waist circumference); metabolic dysfunction (fasting plasma glucose, 2-h plasma glucose, fasting insulin, insulin resistance [homeostasis model assessment of insulin resistance (HOMA-IR)]); and inflammation (high-sensitivity C-reactive protein (hs-CRP)). All analyses were adjusted for age, baseline TV viewing, and potential confounders., Results: Hourly increments of change in TV viewing time were positively associated with BMI (β = 0.50, 95% CI 0.20, 0.81; p = 0.001), waist circumference (β = 1.18, 95% CI 0.49, 1.87; p = 0.001), fasting insulin (β = 38.13%, 95% CI 37.08, 39.20; p = 0.01) and HOMA-IR (β = 37.93%, 95% CI 36.92, 38.98; p = 0.03) in fully adjusted models. Significant associations with BMI, waist circumference, fasting insulin and HOMA-IR were also present in analyses using categories of change in TV viewing time (reduced, same, increased)., Conclusions: The findings suggest that increasing habitual sedentary behavior over time could increase breast cancer risk among postmenopausal women. Further investigation into the role of sedentary behavior in breast cancer etiology is warranted.

Background: The primary purpose of this study was to determine associations of accelerometer-assessed moderate- to vigorous-intensity physical activity (MVPA) and sedentary time with health-related quality of life (HRQoL) and physical function and well-being in colon cancer survivors., Methods: Colon cancer survivors (N = 178) from Alberta, Canada (n = 92) and Western Australia (n = 86) completed a mailed survey that assessed HRQoL (Functional Assessment of Cancer Therapy-Colorectal), physical function and well-being (Trial Outcome Index-Colorectal), and relevant covariates. MVPA and sedentary time were assessed using the Actigraph GT3X+ accelerometer (60-second epochs) via a 7-day monitoring protocol. Average daily MVPA and sedentary time was corrected for wear time and then examined as quartiles., Results: Adjusting for relevant demographic, behavioral, and clinical covariates, a significant difference in HRQoL scores emerged between quartile 1 (Q1) and Q4 (M(diff) = 11.5, P = .038). For physical function and well-being, a significant difference emerged between Q1 and Q4 (M(diff) = 9.1, P = .009). For fatigue, a significant difference emerged between Q1 and Q4 (M(diff) = 7.1, P = .05). Significant differences were also observed for between Q1 and Q3 (M(diff) = 2.4, P = .041), and Q1 and Q4 (M(diff) = 3.5, P = .002) for colorectal cancer-specific symptoms. There were no statistically significant associations of sedentary time with HRQoL, physical function and well-being, fatigue, or colorectal cancer-specific symptoms., Conclusions: Objectively measured MVPA, but not sedentary time, was associated with better HRQoL, physical function and well-being, and colorectal cancer-specific symptoms in colon cancer survivors. For MVPA, differences met or exceeded contemporary cutpoints for determining clinically important differences., (© 2014 American Cancer Society.)

Background: Most sedentary behavior measures focus on occupational or leisure-time sitting. Our aim was to develop a comprehensive measure of adult sedentary behavior and establish its measurement properties., Method: The SIT-Q was developed through expert review (n = 7), cognitive interviewing (n = 11) and pilot testing (n = 34). A convenience sample of 82 adults from Calgary, Alberta, Canada, participated in the measurement property study. Test-retest reliability was assessed by intraclass correlation coefficients (ICCs) comparing two administrations of the SIT-Q conducted one month apart. Convergent validity was established using Spearman's rho, by comparing the SIT-Q estimates of sedentary behaviour with values derived from a 7-Day Activity Diary., Results: The SIT-Q exhibited good face validity and acceptability during pilot testing. Within the measurement property study, the ICCs for test-retest reliability ranged from 0.31 for leisure-time computer use to 0.86 for occupational sitting. Total daily sitting demonstrated substantial correlation (ICC = 0.65, 95% CI: 0.49, 0.78). In terms of convergent validity, correlations varied from 0.19 for sitting during meals to 0.76 for occupational sitting. For total daily sitting, estimates derived from the SIT-Q and 7 Day Activity Diaries were moderately correlated (ρ = 0.53, p < 0.01)., Conclusion: The SIT-Q has acceptable measurement properties for use in epidemiologic studies.

Background: Sedentary behavior may independently contribute to morbidity and mortality among survivors of colorectal cancer. In the current study, the authors assessed whether a telephone-delivered multiple health behavior change intervention had an effect on the sedentary behavior of recently diagnosed colorectal cancer survivors., Methods: A total of 410 participants were recruited through the Queensland Cancer Registry and randomized to the health coaching (intervention) or usual-care (control) group. Eleven health coaching sessions addressing multiple health behaviors, including sedentary behavior, were delivered over a period of 6 months. Data were collected at baseline (before randomization), at 6 months, and at 12 months via a telephone interview., Results: At 12 months, there was a significant decrease noted in the hours per day of sedentary time in both the health coaching (-1.21; 95% confidence interval [95% CI], -1.71 to -0.70) and usual-care groups (-0.55; 95% CI, -1.06 to -0.05), but the between-group difference was not found to be statistically significant (-0.65; 95% CI, -1.37 to 0.06 [P = .07]). In stratified subgroup analyses, the multiple health behavior change intervention was found to have a significant effect on total sedentary time (hours/day) at 12 months in survivors of colorectal cancer who were aged > 60 years (-0.90; 95% CI, -1.80 to -0.01 [P = .05]), male (-1.33; 95% CI, -2.44 to -0.21 [P = .02]), and nonobese (-1.10; 95% CI, -1.96 to -0.25; [P = .01])., Conclusions: Incorporating simple messages about limiting sedentary behaviors into a multiple health behavior change intervention was found to have modest effects on sedentary behavior. A sedentary behavior-specific intervention strategy may be required to achieve substantial changes in sedentary behavior among colorectal cancer survivors., (© 2014 American Cancer Society.)

Purpose: The objective of this study is to examine test-retest reliability, criterion validity, and absolute agreement of a self-report, last 7-d sedentary behavior questionnaire (SIT-Q-7d), which assesses total daily sedentary time as an aggregate of sitting/lying down in five domains (meals, transportation, occupation, nonoccupational screen time, and other sedentary time). Dutch (DQ) and English (EQ) versions of the questionnaire were examined., Methods: Fifty-one Flemish adults (ages 39.4 ± 11.1 yr) wore a thigh accelerometer (activPAL3™) and simultaneously kept a domain log for 7 d. The DQ was subsequently completed twice (median test-retest interval: 3.3 wk). Thigh-acceleration sedentary time was log annotated to create comparable domain-specific and total sedentary time variables. Four hundred two English adults (ages 49.6 ± 7.3 yr) wore a combined accelerometer and HR monitor (Actiheart) for 6 d to objectively measure total sedentary time. The EQ was subsequently completed twice (median test-retest interval: 3.4 wk). In both samples, the questionnaire reference frame overlapped with the criterion measure administration period. All participants had five or more valid days of criterion data, including one or more weekend day., Results: Test-retest reliability (intraclass correlation coefficient (95% CI)) was fair to good for total sedentary time (DQ: 0.68 (0.50-0.81); EQ: 0.53 (0.44-0.62)) and poor to excellent for domain-specific sedentary time (DQ: from 0.36 (0.10-0.57) (meals) to 0.66 (0.46-0.79) (occupation); EQ: from 0.45 (0.35-0.54) (other sedentary time) to 0.76 (0.71-0.81) (meals)). For criterion validity (Spearman rho), significant correlations were found for total sedentary time (DQ: 0.52; EQ: 0.22; all P <0.001). Compared with domain-specific criterion variables (DQ), modest-to-strong correlations were found for domain-specific sedentary time (from 0.21 (meals) to 0.76 (P < 0.001) (screen time)). The questionnaire generally overestimated sedentary time compared with criterion measures., Conclusion: The SIT-Q-7d appears to be a useful tool for ranking individuals in large-scale observational studies examining total and domain-specific sitting.

Sedentary behavior (sitting time) has been proposed as an independent risk factor for some cancers; however, its role in the development of prostate cancer has not been determined. We examined the prospective associations of self-reported daily sitting time and daily television/video viewing time with the risk of developing or dying from prostate cancer among 170,481 men in the NIH-AARP Diet and Health Study. We estimated HRs and 95% confidence intervals (CI) using Cox proportional hazards regression. Between 1996 and 2006, there were 13,751 incident (including 1,365 advanced) prostate cancer cases identified; prostate cancer mortality (through 2008) was 669. No strong or significant association with prostate cancer risk was seen in fully adjusted models for either daily sitting or television/video time. There were some suggestions of effect modification by body mass index (BMI; interaction for television/video time and BMI, P = 0.02). For total prostate cancer risk, television/video time was associated with a slightly elevated, but nonsignificant, increase amongst obese men (HR = 1.28; 95% CI, 0.98-1.69); a null association was observed amongst overweight men (HR = 1.04; 0.89-1.22); and, for men with a normal BMI, television/video time was associated with a nonsignificant risk decrease (HR = 0.82; 95% CI, 0.66-1.01). Similar patterns were observed for total daily sitting and television/video time in advanced prostate cancer and prostate cancer mortality. Sedentary behavior seems to play a limited role in the development of prostate cancer; however, we cannot rule out potential effect modification by BMI or the impact of measurement error on results., (©2014 AACR.)

Purpose: Sedentary behavior may be a unique risk factor for some cancers, including breast cancer. The objective of this study was to determine the association between lifetime occupational sitting and likelihood of breast cancer., Methods: A case-control study of 2,452 women was conducted in Alberta, Canada, between 1995 and 1997. A comprehensive measure of lifetime physical activity assessed frequency and duration of sedentary jobs. Logistic regression estimated the odds of being diagnosed with breast cancer across quartiles of lifetime occupational sitting, by menopausal status and family history of breast cancer, and within body mass index categories and physical activity quartiles., Results: There was no association between occupational sitting and breast cancer among pre-menopausal women and women with a family history of breast cancer. Unexpectedly, higher amounts of occupational sitting were associated with lower odds of breast cancer in post-menopausal women (top versus bottom categories of occupational sitting OR = 0.71, 95 % CI 0.52, 0.97), women without a family history of breast cancer (OR = 0.77, 95 % CI 0.60, 1.00), and women in the third highest quartile of total lifetime physical activity (OR = 0.57, 95 % CI 0.33, 0.97)., Conclusion: Occupational sitting levels were lower than would be expected in a contemporary study. Exposures may have been insufficient to make a determinable contribution to breast cancer risk.

Cancer survival is associated with considerable physical and psychosocial burden. Broadly accessible, nonpharmacologic measures that may extend disease-free survival, limit comorbid disease, and enhance quality of life are required. Sedentary behavior (too much sitting) is now understood to be a health risk that is additional to, and distinct from, the hazards of too little exercise. Of particular note, it is associated with adiposity, insulin resistance, and markers of inflammation. Therefore, it is plausible that sedentary behavior may contribute to adverse cancer outcomes (disease progression, recurrence, or death) and to the development of comorbid chronic disease. Initial studies indicate that cancer survivors spend two-thirds of their waking hours sitting. Among colorectal cancer survivors, sedentary behavior may contribute to all-cause and disease-specific mortality, weight gain, comorbid cardiovascular disease, and diminished quality of life. There is a need for dose-response evidence, and for a broader understanding of the underlying mechanisms by which prolonged sitting time may affect cancer survivors' health., (Copyright © 2013 American Cancer Society.)

Physical activity reduces the risk of postmenopausal breast cancer through multiple inter-related biologic mechanisms; sedentary time may contribute additionally to this risk. We examined cross-sectional associations of objectively assessed physical activity and sedentary time with established biomarkers of breast cancer risk in a population-based sample of postmenopausal women. Accelerometer, anthropometric and laboratory data were available for 1,024 (n = 443 fasting) postmenopausal women in the U.S. National Health and Nutrition Examination Survey 2003-2006. Associations of quartiles of the accelerometer variables (moderate- to vigorous-intensity activity, light-intensity activity and sedentary time per day; average length of active and sedentary bouts) with the continuous biomarkers were assessed using linear regression models. Following adjustment for potential confounders, including sedentary time, moderate- to vigorous-intensity activity had significant (P < 0.05), inverse associations with all biomarker outcomes (body mass index, waist circumference, C-reactive protein, fasting plasma glucose, fasting insulin and homeostasis model assessment of insulin resistance). Light-intensity activity and sedentary time were significantly associated in fully adjusted models with all biomarkers except fasting glucose. Active bout length was associated with a smaller waist circumference and lower C-reactive protein levels, while sedentary bout length was associated with a higher BMI. The associations of objectively assessed moderate- to vigorous-intensity activity with breast cancer biomarkers are consistent with the established beneficial effects of self-reported exercise on breast cancer risk. Our findings further suggest that light-intensity activity may have a protective effect, and that sedentary time may independently contribute to breast cancer risk.

Background: Studies provide conflicting evidence for the protective effects of moderate-to-vigorous-intensity physical activity on depression. Recent evidence suggests that sedentary behaviors may also be associated with depression., Purpose: To examine the associations of accelerometer-derived moderate-to-vigorous-intensity physical activity and sedentary time with depression among a population-based sample., Methods: Cross-sectional study using 2,862 adults from the 2005-2006 US National Health and Nutrition Examination Survey. ActiGraph accelerometers were used to derive both moderate-to-vigorous-intensity physical activity and sedentary time., Results: Depression occurred in 6.8% of the sample. For moderate-to-vigorous-intensity physical activity, compared with those in quartile 1 (least active), significantly lower odds of depression were observed for those participants in quartiles 2 (OR=0.55, 95% CI, 0.34 to 0.89), 3 (OR=0.49, 95% CI, 0.26 to 0.93), and 4 (most active) (OR=0.37, 95% CI, 0.20 to 0.70) (p for trend p<0.01). In overweight/obese participants only, those in quartile 4 (most sedentary) had significantly higher odds for depression than those in quartile 1 (least sedentary) [quartile 3 vs 1 (OR=1.94, 95% CI, 1.01 to 3.68) and 4 vs 1 (OR=3.09, 95% CI, 1.25 to 7.68)]., Conclusion: The current study identified lower odds of depression were associated with increasing moderate-to-vigorous-intensity physical activity and decreasing sedentary time, at least within overweight/obese adults., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Background: Television viewing time independent of physical activity is associated with a number of chronic diseases and related risk factors; however, its relationship with chronic kidney disease is unknown., Purpose: The purpose of this study is to examine the cross-sectional and prospective relationships of television viewing time with biomarkers of chronic kidney disease., Methods: Participants of the Australian Diabetes, Obesity and Lifestyle Study attended the baseline (n = 10,847) and 5-year follow-up (n = 6,293) examination., Results: Television viewing was significantly associated with increased odds of prevalent albuminuria and low estimated glomerular filtration rate. In the gender-stratified analyses this pattern was seen for men, but not for women. In the longitudinal analyses, odds of de novo albuminuria and low estimated glomerular filtration rate were increased only in unadjusted models., Conclusions: Television viewing time may be directly related to markers of chronic kidney disease and through intertwined associated risk factors such as diabetes, hypertension, and obesity.

Background: Sedentary behavior (prolonged sitting or reclining characterized by low energy expenditure) is associated with adverse cardiometabolic profiles and premature cardiovascular mortality. Less is known for cancer risk. The purpose of this review is to evaluate the research on sedentary behavior and cancer, to summarize possible biological pathways that may underlie these associations, and to propose an agenda for future research., Methods: Articles pertaining to sedentary behavior and (a) cancer outcomes and (b) mechanisms that may underlie the associations between sedentary behavior and cancer were retrieved using Ovid and Web of Science databases., Results: The literature review identified 18 articles pertaining to sedentary behavior and cancer risk, or to sedentary behavior and health outcomes in cancer survivors. Ten of these studies found statistically significant, positive associations between sedentary behavior and cancer outcomes. Sedentary behavior was associated with increased colorectal, endometrial, ovarian, and prostate cancer risk; cancer mortality in women; and weight gain in colorectal cancer survivors. The review of the literature on sedentary behavior and biological pathways supported the hypothesized role of adiposity and metabolic dysfunction as mechanisms operant in the association between sedentary behavior and cancer., Conclusions: Sedentary behavior is ubiquitous in contemporary society; its role in relation to cancer risk should be a research priority. Improving conceptualization and measurement of sedentary behavior is necessary to enhance validity of future work., Impact: Reducing sedentary behavior may be a viable new cancer control strategy., (©2010 AACR.)