Search

Background: Sedentary behaviour can be associated with poor mental health, but it remains unclear whether all types of sedentary behaviour have equivalent detrimental effects., Aims: To model the potential impact on depression of replacing passive with mentally active sedentary behaviours and with light and moderate-to-vigorous physical activity. An additional aim was to explore these relationships by self-report data and clinician diagnoses of depression., Method: In 1997, 43 863 Swedish adults were initially surveyed and their responses linked to patient registers until 2010. The isotemporal substitution method was used to model the potential impact on depression of replacing 30 min of passive sedentary behaviour with equivalent durations of mentally active sedentary behaviour, light physical activity or moderate-to-vigorous physical activity. Outcomes were self-reported depression symptoms (cross-sectional analyses) and clinician-diagnosed incident major depressive disorder (MDD) (prospective analyses)., Results: Of 24 060 participants with complete data (mean age 49.2 years, s.d. 15.8, 66% female), 1526 (6.3%) reported depression symptoms at baseline. There were 416 (1.7%) incident cases of MDD during the 13-year follow-up. Modelled cross-sectionally, replacing 30 min/day of passive sedentary behaviour with 30 min/day of mentally active sedentary behaviour, light physical activity and moderate-to-vigorous activity reduced the odds of depression symptoms by 5% (odds ratio 0.95, 95% CI 0.94-0.97), 13% (odds ratio 0.87, 95% CI 0.76-1.00) and 19% (odds ratio 0.81, 95% CI 0.93-0.90), respectively. Modelled prospectively, substituting 30 min/day of passive with 30 min/day of mentally active sedentary behaviour reduced MDD risk by 5% (hazard ratio 0.95, 95% CI 0.91-0.99); no other prospective associations were statistically significant., Conclusions: Substituting passive with mentally active sedentary behaviours, light activity or moderate-to-vigorous activity may reduce depression risk in adults.

Objective: Regular physical activity (PA) is associated with less self-reported anxiety, but prospective studies linked to clinician diagnoses of anxiety disorder remain scarce. We examined whether the PA levels recommended for general health are related to anxiety symptoms and disorders., Method: In total, 43,863 Swedish adults were surveyed in 1997 and responses linked to medical registers until 2010. Weekly durations of habitual moderate and vigorous leisure time PA were self-reported. Cross-sectional and prospective relationships between the total duration (minutes) of PA, 0-149 ('below'), 150-299 ('achieve'), and ≥300 min ('exceed') with self-reported anxiety symptoms and incident anxiety disorder were explored. Associations were explored using logistic and Cox proportional hazard regression models., Results: Of 27,053 participants with complete data (mean age = 49.0 years, SD = 15.9, 66% female), 76% met the recommended duration of PA (≥150 min), and 38% exceeded this duration. At baseline, 2573 participants (9.5%) reported elevated anxiety symptoms. In cross-sectional analyses, engaging in ≥150 min of MVPA/week was associated with 24% (OR = 0.76, 95% CI = 0.68-0.86) lower odds of anxiety symptoms. Exceeding the weekly duration was associated with 36% (OR = 0.64, 95% CI = 0.57-0.72) lower odds. During the 13-year follow-up, 198 incident cases of anxiety disorder (0.8%) were identified. No significant prospective relationships were found., Conclusions: Engaging in leisure time PA at levels recommended for general health may reduce the risk of elevated anxiety symptoms. As the incidence of anxiety disorder was likely under-estimated, further prospective studies are needed to determine the relationship between PA and incident anxiety disorder., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Regular physical activity (PA) appears to protect against the emergence of depression, but prospective studies linked to clinician diagnoses of major depressive disorder (MDD) remain scarce. It is also unclear whether PA levels recommended for general health are prospectively related to depression onset. We explored these relationships in a cohort of adults followed over 13 years. In total, 43,863 Swedish adults were surveyed in 1997 and responses linked to clinician-diagnosed MDD obtained from specialist medical registers until 2010. Weekly durations of habitual moderate (including walking) and vigorous PA were self-reported. Relationships between total durations of PA, 0-149 ('below'), 150-299 ('achieve'), and ≥300 min ('exceed') with incident MDD were explored using survival analysis with Cox proportional hazards regression. Models were adjusted for relevant covariates. Those with indications of depression at baseline were removed from the primary analyses. Of 25,520 participants with complete data (mean age = 49 years, SD = 16, 65% female), 76% met the recommended weekly duration of PA (≥150 min), and 38% exceeded this duration (≥300 min). During 13-years follow-up 549 MDD cases (1.5%) were identified (incidence rate = 111 cases per 100,000 person-years). Compared to participants who were below, those who exceeded the recommended weekly duration (≥300 min/week) had 29% reduced risk of depression onset (HR 0.71, 95% CI = 0.53-0.96). A non-significant inverse association was observed among those who achieved the minimum duration of 150-min/week (HR 0.86, 95% CI = 0.64-1.14). Habitual PA levels that exceed the duration recommended for general health may reduce the risk of clinician-diagnosed major depression in adults., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Physical activity has been inversely associated with the risk of hip fracture, however, few studies have been conducted on the contributions from different domains of physical activity. This study was performed to investigate the association between daily household activities, leisure time physical activity, work-related physical activity and total physical activity during a 24-h period, and the risk of hip fracture. In the Swedish National March Cohort we followed 23,881 men and women aged of 50 and over from 1997 until 2010. Information on domain-specific physical activity was collected at baseline using a questionnaire. We fitted separate multivariable adjusted Cox proportional hazard models to each domain to obtain hazard ratios (HRs) with 95% confidence intervals (CIs). Each model was mutually adjusted for the other domains of physical activity. During a mean follow-up period of 12.2 years we identified 824 incidents of hip fracture. Subjects who spent less than 1 h per week engaged in daily household activities had an 85% higher risk of hip fracture than subjects spending ≥6 h per week carrying out daily household activities (HR 1.85; 95% CI 1.01-3.38). Subjects engaged in leisure time physical activities for >3.1 MET-h/day had a 24% lower risk of hip fracture (HR 0.76; 95% CI 0.59-0.98) than subjects spending <1.1 MET-h/day performing such activities. No association was found between hip fracture and work-related or total physical activity. We conclude that daily household activities and leisure time physical activity may independently decrease the risk of hip fracture in those aged 50 and over.

Although keeping a healthy weight and being physically active are among the few modifiable risk factors for post-menopausal breast cancer, the possible interaction between these two risk factors remains to be established. We analyzed prospectively a cohort of 19,196 women who provided detailed self-report on anthropometric measures, physical activity and possible confounders at enrollment in 1997. We achieved complete follow-up through 2010 and ascertained 609 incident cases of post-menopausal invasive breast cancer. We calculated metabolic energy turnover (MET h/day) per day and fitted Cox proportional hazards models to estimate hazard ratios (HRs) with 95 % confidence intervals (CIs). The incidence of post-menopausal breast cancer among obese women (BMI ≥ 30 kg/m(2)) was 58 % higher (HR 1.58, CI 1.16-2.16) than in women of normal weight (18.5 ≤ BMI < 25). Women in the lowest tertile of total physical activity (< 31.2 MET h/day) had 40 % higher incidence of post-menopausal breast cancer (HR 1.40, CI 1.11-1.75) than those in the highest tertile (≥ 38.2 MET h/day). The excess incidence linked to these two factors seemed to combine in an approximately additive manner; the incidence among the most obese and sedentary women was doubled (HR 2.07, CI 1.31-3.25) compared with the most physically active women with normal weight. No heterogeneity of the physical activity-linked risk ratios across strata of BMI was detected (p value for interaction = 0.98). This prospective study revealed dose-dependent, homogenous inverse associations between post-menopausal breast cancer incidence and physical activity across all strata of BMI, and between post-menopausal breast cancer incidence and BMI across all strata of physical activity, with no evidence of additive or multiplicative interaction between the two, suggesting independent effects.

Objective: Adolescents' perception of overweight often disagrees with objective measurements; if factors explaining this discrepancy are potentially modifiable is unclear., Methods: We analyzed cross-sectional data from a cohort of 2,001 Swedish adolescents (1,026 females, 975 males) at the age of 15 years in 2003. Erroneous perception of overweight was defined as the perception of being overweight in relation to normal or lower than normal BMI (kg/m(2)). BMI measured by the school nurse at 11 years, school-based education on nutrition/physical activity, smoking, alcohol consumption, physical activity, and healthy/unhealthy eating were examined as potential predictors/correlates of overweight misperception in multivariate logistic regression models., Results: At the age of 15 years, 32% of girls and 10% of boys misclassified themselves as overweight. Overweight at 11 years predicted misperception of overweight 4 years later (adjusted odds ratio (OR) = 2.3, 95% confidence interval (95% CI) = 1.4-3.6 in boys; OR = 1.9, 95% CI = 1.3-2.8 in girls). Among girls, smoking was associated with a higher probability of misperception (adjusted OR = 1.6, 95% CI = 1.2-2.2). Among boys, physical activity (>6 h/ week) was associated with a lower probability of misperception (OR = 0.4, 95% CI = 0.2-0.7). No association was observed with school-based education on nutrition and physical activity., Conclusion: Preventing overweight in pre-adolescence may be a way to avoid later unjustified weight concerns in adolescence., (Copyright © 2011 S. Karger AG, Basel.)

The health benefits of physical activity (PA) have been well documented. However, there is less research investigating whether or not these health benefits might differ among males and females or among subjects characterized by different levels of body mass index (BMI), waist-to-hip ratio (WHR), and waist circumference (WC). Baseline total PA, BMI, WHR and waist circumference were measured in 14,585 men and 26,144 women who participated in the Swedish National March. Their effects on all-cause mortality were analyzed with a follow-up time of almost 10 years. Sedentary men with a BMI ≥ 30 had a 98% (95% CI: 30-201%) increased risk of mortality compared to normal weight men with a high level of total PA. The same trend was observed for sedentary men with high WHR or waist circumference, compared to lean and highly active men. Sedentary women with a waist circumference of 88 cm or more had almost doubled, i.e. 97% (95% CI: 35-189%) increased mortality risk compared to physically active women with a waist circumference below 80 cm. BMI in men, but waist circumference in women better forecast all-cause mortality. We found no substantial effect modification between different measures of adiposity and physical activity-physical inactivity and obesity seem to increase total mortality risk independently and additively.

We compared the results of self-estimates of physical activity obtained with a novel instrument (the Energy Expenditure Questionnaire, EEQ) to those obtained from questions typically asked in epidemiological investigations (reference method) in a cohort of 42,150 Swedish men and women, aged 18-94. In the EEQ, participants were asked to report total physical activity by estimating the total time during a typical day and night spent on different physical activity intensity levels from the lowest (corresponding to lying in bed, 0.9 Metabolic Energy Turnover; MET) to the highest, (exceeding the intensity of to shovelling snow by hand, i.e., >6 MET). As a comparison, they also estimated hours per week devoted to household chores, commuting and leisure time physical activities classified as; light, moderate and heavy. The average physical activity estimated with the EEQ was 1.36 MET or 32.6 METh/day or 2,341 kcal/day. In comparison, physical activity estimated with the reference method represented no more than 17% of this amount. The Spearman's correlation coefficient between the two measures was 0.26. Using EEQ, men reported significantly more physical activity than women (mean = 36.3 vs. 30.6 METh/day). Body mass index (BMI) > or = 25, education > or = 12 years, and age > or = 60 years were significantly associated with lower physical activity. Questions focusing on leisure time exercise and a few other selected activities provide estimates of activity that correlate poorly with self-reported total energy output from all physical activity and inactivity. Investigators need to be more explicit about which component of activity they investigate.

Aim of this study was to assess the validity of a short self-administered physical activity questionnaire, intended to measure past year total daily physical activity, by comparison with activity records and accelerometers. Over a 1-year period, data from a questionnaire, 7-day activity records and accelerometers were obtained from a subset of 116 women between the ages of 56 and 75 years from the population-based Swedish Mammography Cohort. We estimated concordance correlations as measure of validity, deattenuated for intraindividual variation in the reference method. Deattenuated concordance correlations comparing total daily activity measured by the questionnaire with the accelerometers and the records were 0.38 (95% CI: 0.22-0.54) and 0.64 (95% CI: 0.45-0.83), respectively. Validity of leisure-time activity (walking/bicycling and exercise) and inactivity (watching TV/reading) estimates comparing the records with the questionnaire were 0.42 (95% CI: 0.22-0.62) and 0.52 (95% CI: 0.36-0.69), respectively. These data indicate that the average past year total physical activity, leisure-time activity and inactivity can be estimated with a reasonable validity using our short self-administered questionnaire.

Few studies have evaluated the reliability of a self-administered current and historical physical activity questionnaire (PAQ) among middle-aged and elderly women. We evaluated the reliability of a self-administered PAQ designed to assess total (24 h) current and historical physical activity at age 15, 30, and 50 years, which was completed by a subgroup of 303 women aged 56-75 years from the Swedish Mammography Cohort (SMC). Total physical activity covered occupational and household activity as well as walking/bicycling, exercise, and inactivity (sitting watching TV/reading). Reliabilities (1-year test-retest) of continuous activity measures in metabolic equivalents were evaluated using an intraclass correlation coefficient (ICC); classification consistency was evaluated using sensitivity and specificity statistics. The ICC for total current physical activity was 0.69; for specific types of activities the ICC ranged from 0.49 to 0.59; for historical physical activity, the reliabilities for total activity ranged from 0.75 for age 50 to 0.81 for age 30 years, being substantial for occupational activities (ICC = 0.73-0.75), and fair to moderate for inactivity (ICC = 0.31-0.60). These data indicate that the PAQ used in the SMC is a satisfactory and reproducible measure of current and historical physical activity, for total as well as for different types of activities.

Improved methods for quantitative self-reports of total physical activity in epidemiological studies are needed. We evaluated randomly selected individuals' ability to integrate their perception of physical activity over time to produce an estimate of the "usual" level, using a novel instrument for self-quantification of energy expenditure. A population-based sample of 418 Swedish men and women, age 20-59, completed a questionnaire containing the new instrument. For validation, three 24 hour recalls by phone served as gold standard. Reproducibility was assessed through administering the instrument another three times. The validation involved 133 subjects and another 160 completed the reproducibility evaluation. Pearson correlation between usual daily energy expenditure measured by the instrument and the mean of the 24 hour recalls was 0.73. After subdividing the self-reported daily energy expenditure and the mean of the 24 hour recalls into quintiles, 83.5% of the participants remained in the same quintile, or one quintile apart. There was a tendency towards overestimation of usual daily physical activity. This was significantly associated with low education. Reproducibility showed an intraclass correlation of 0.55. Although integrated reports of usual daily energy expenditure over longer periods seem to be afflicted with a tendency of overestimation, total energy expenditure can be estimated with reasonable validity and reproducibility using our instrument.

Introduction/purpose: Despite a large public health interest in physical activity and its role in obesity and other chronic diseases, only few reports to date have addressed total levels and trends of physical activity. We have studied in a cross-sectional setting with a retrospective recall of physical activity an association of levels of total physical activity and different types of activities with age and with calendar-time., Methods: In a population-based study of 33,466 men aged 45-79 yr in central Sweden, information on physical activity and other lifestyle factors was collected through a self-administered questionnaire. Level of total activity at ages 15, 30, and 50 yr was assessed quantitatively, based on six questions on different activities: work/occupation, housework, walking/bicycling, exercise, inactive leisure time, and sleeping. The physical activity levels were measured as metabolic equivalents, MET-hours per days., Results: Total daily physical activity decreased at age 30 yr (-1.6%, 95% CI: -1.7, -1.4) and at age 50 yr (-3.9%, 95% CI: -4.0, -3.7) compared with age 15 yr. Total physical activity decreased over a period of 60 yr in all three separate age groups (-9.1% among 15-yr-olds, 95% CI: -9.8, -8.5; -2.3% among 30-yr-olds 95% CI: -3.0, -1.6; and -2.9% among 50-yr-olds, 95% CI: -3.4, -2.5)., Conclusion: These negative trends in physical activity observed by age and with time might explain the trends in increasing prevalence of obesity.

Background: There is a need to find new methods that can enhance the individuals’ engagement in self-care and increase compliance to a healthy lifestyle for the prevention of noncommunicable diseases and improved quality of life. Mobile health (mHealth) apps could provide large-scale, cost-efficient digital solutions to implement lifestyle change, which as a corollary may enhance quality of life. Objective: Here we evaluate if the use of a smartphone-based self-management system, the Health Integrator app, with or without telephone counseling by a health coach, had an effect on clinical variables (secondary outcomes) of importance for noncommunicable diseases. Methods: The study was a 3-armed parallel randomized controlled trial. Participants were randomized to a control group or to 1 of 2 intervention groups using the Health Integrator app with or without additional telephone counseling for 3 months. Clinical variables were assessed before the start of the intervention (baseline) and after 3 months. Due to the nature of the intervention, targeting lifestyle changes, participants were not blinded to their allocation. Robust linear regression with complete case analysis was performed to study the intervention effect among the intervention groups, both in the entire sample and stratifying by type of work (office worker vs bus driver) and sex. Results: Complete data at baseline and follow-up were obtained from 205 and 191 participants, respectively. The mean age of participants was 48.3 (SD 10) years; 61.5% (126/205) were men and 52.2% (107/205) were bus drivers. Improvements were observed at follow-up among participants in the intervention arms. There was a small statistically significant effect on waist circumference (β=–0.97, 95% CI –1.84 to –0.10) in the group receiving the app and additional coach support compared to the control group, but no other statistically significant differences were seen. However, participants receiving only the app had statistically significantly lower BMI (β=–0.35, 95% CI –0.61 to –0.09), body weight (β=–1.08, 95% CI –1.92 to –0.26), waist circumference (β=–1.35, 95% CI –2.24 to –0.45), and body fat percentage (β=–0.83, 95% CI –1.65 to –0.02) at follow-up compared to the controls. There was a statistically significant difference in systolic blood pressure between the two intervention groups at follow-up (β=–3.74, 95% CI –7.32 to –0.16); no other statistically significant differences in outcome variables were seen. Conclusions: Participants randomized to use the Health Integrator smartphone app showed small but statistically significant differences in body weight, BMI, waist circumference, and body fat percentage compared to controls after a 3-month intervention. The effect of additional coaching together with use of the app is unclear. [ABSTRACT FROM AUTHOR]

Physical exercise has been suggested to be neuroprotective in the nigrostriatal system. Yang et al. prospectively investigate the association between physical activity and Parkinson’s disease risk in 43 368 Swedish subjects. They show that increased levels of physical activity are associated with a lower risk of Parkinson’s disease.See Tanner and Comella (doi:10.1093/brain/awu351) for a scientific commentary on this article.Physical exercise has been associated with neuroprotective effects in the nigrostriatal dopaminergic system. To examine the impact of physical activity on Parkinson’s disease risk prospectively, we followed 43 368 individuals who provided extensive information on physical activity at baseline. We estimated hazard ratios with 95% confidence intervals using Cox proportional hazards regression. During an average of 12.6 years of follow-up, 286 incident Parkinson’s disease cases were identified. In males, there was an inverse association with Parkinson’s disease for total physical activity (hazard ratio 0.55, 95% confidence interval 0.35–0.87 for medium versus low level), for sum of household, commuting and leisure time exercise (hazard ratio 0.53, 95% confidence interval 0.33–0.85 for high versus low level), and for household and commuting physical activity specifically (hazard ratio 0.50, 95% confidence interval 0.31–0.81 for >6 versus <2 h per week). No association was observed for leisure time exercise or occupational physical activity with Parkinson’s disease, among either males or females. Meta-analysis of the present study and five previous prospective studies showed a pooled hazard ratio of 0.66 (95% confidence interval 0.57–0.78) for highest versus lowest physical activity level. Our results indicate that a medium level of physical activity lowers Parkinson’s disease risk. [ABSTRACT FROM AUTHOR]

The nature of the association between levels of physical activity and risk of heart failure is little known. We investigated nonlinear associations of total and leisure time physical activity with risk of heart failure.In 1997, 39 805 persons without heart failure completed a questionnaire of lifestyle factors and medical history. We used Cox regression models to investigate total (adjusting for education and previous myocardial infarction) and direct (multivariable-adjusted) effects of self-reported total and leisure time physical activity on risk of heart failure of any cause and heart failure of nonischemic origin. Heart failure diagnoses were obtained until December 31, 2010. Higher leisure time physical activity was associated with lower risk of heart failure of any cause; hazard ratio of the total effect of leisure time physical activity was for fifth versus first quintile 0.54; 95% confidence interval was 0.44 to 0.66. The direct effect was similar. High total daily physical activity level was associated with lower risk of heart failure, although the effect was less pronounced than for leisure time physical activity (total effect hazard ratio, 0.81; 95% confidence interval, 0.69-0.95; fifth versus first quintile). A similar direct effect observed.Leisure time physical activity was inversely related to risk of developing heart failure in a dose-response fashion. This was reflected in a similar but less pronounced association of total physical activity with risk of heart failure. Only part of the effects appeared to be mediated by traditional risk factors. [ABSTRACT FROM AUTHOR]

Purpose: Few epidemiological studies have been conducted among middle-aged women on long-term total and specific physical activity (PA) trends. We studied in a cross-sectional setting the relationship of self-reported total daily PA with age and calendar time. Methods: In a population-based cohort of 38,988 women aged 49-83 yr in central Sweden, information was collected on physical activity, such as work or occupation, household work, walking or bicycling, exercise, watching TV or reading, and other lifestyle factors through a self-administered questionnaire. Total and specific daily PA levels at ages 15, 30, and 50 yr were recalled retrospectively and measured as metabolic equivalents (MET·h·d-1). Results: Total PA level linearly decreased with calendar time in all three age groups (slope for 5-yr change in calendar time among those 15 yr of age = -0.82; 95% confidence interval (CI), -0.86 to -0.78; among those 30 yr of age = -0.42; 95% CI, -0.45 to -0.38; and among those 50 yr of age = -0.62; 95% CI, -0.66 to -0.58). High-intensity activities such as walking or bicycling decreased by 0.21 MET·h·d-1 (95% CI, -0.22 to -0.20) every 5-calendar-year change among adolescents between the 1930s and 1960s. Total activity level decreased in all age groups by an average of approximately 3 MET·h-1·d-1, corresponding to approximately 45 min of brisk walking. Conclusions: Our results suggest that intervention efforts aimed at engaging in healthful amounts of physical activity are needed throughout the life cycle. [ABSTRACT FROM AUTHOR]

Background: Lifestyle-related health problems are an important health concern in the transport service industry. Web- and telephone-based interventions could be suitable for this target group requiring tailored approaches.Objective: To evaluate the effect of tailored Web-based health feedback and optional telephone coaching to improve lifestyle factors (body mass index-BMI, dietary intake, physical activity, stress, sleep, tobacco and alcohol consumption, disease history, self-perceived health, and motivation to change health habits), in comparison to no health feedback or telephone coaching.Methods: Overall, 3,876 employees in the Swedish transport services were emailed a Web-based questionnaire. They were randomized into: control group (group A, 498 of 1238 answered, 40.23%), or intervention Web (group B, 482 of 1305 answered, 36.93%), or intervention Web + telephone (group C, 493 of 1333 answered, 36.98%). All groups received an identical questionnaire, only the interventions differed. Group B received tailored Web-based health feedback, and group C received tailored Web-based health feedback + optional telephone coaching if the participants' reported health habits did not meet the national guidelines, or if they expressed motivation to change health habits. The Web-based feedback was fully automated. Telephone coaching was performed by trained health counselors. Nine months later, all participants received a follow-up questionnaire and intervention Web + telephone. Descriptive statistics, the chi-square test, analysis of variance, and generalized estimating equation (GEE) models were used.Results: Overall, 981 of 1473 (66.60%) employees participated at baseline (men: 66.7%, mean age: 44 years, mean BMI: 26.4 kg/m(2)) and follow-up. No significant differences were found in reported health habits between the 3 groups over time. However, significant changes were found in motivation to change. The intervention groups reported higher motivation to improve dietary habits (144 of 301 participants, 47.8%, and 165 of 324 participants, 50.9%, for groups B and C, respectively) and physical activity habits (181 of 301 participants, 60.1%, and 207 of 324 participants, 63.9%, for B and C, respectively) compared with the control group A (122 of 356 participants, 34.3%, for diet and 177 of 356 participants, 49.7%, for physical activity). At follow-up, the intervention groups had significantly decreased motivation (group B: P<.001 for change in diet; P<.001 for change in physical activity; group C: P=.007 for change in diet; P<.001 for change in physical activity), whereas the control group reported significantly increased motivation to change diet and physical activity (P<.001 for change in diet; P<.001 for change in physical activity).Conclusion: Tailored Web-based health feedback and the offering of optional telephone coaching did not have a positive health effect on employees in the transport services. However, our findings suggest an increased short-term motivation to change health behaviors related to diet and physical activity among those receiving tailored Web-based health feedback. [ABSTRACT FROM AUTHOR]

Background: As distinct from mentally-active sedentary behaviors (e.g. reading), passive sedentary behaviors (e.g. TV-viewing) have been linked to a higher risk of depression, but the underlying mechanisms are unclear. We examined the potential mediating role of sleep problems in prospective relationships of passive sedentary behaviors with major depressive disorder (MDD).Method: In 1997, 43 863 adults were surveyed and responses linked to clinician diagnoses of MDD until 2010. The questionnaire included items on sedentary behavior and sleep problems (Karolinska Sleep Questionnaire). Cox proportional hazard models and the 'counterfactual approach' were used to identify potential mediating effects of sleep problems in the association of passive sedentary behavior and MDD.Results: Of the total sample, 3,065 (7.6%) were excluded for having indications of depression at baseline. Of 33,116 participants with complete data (mean age = 51.3 years, SD = 15.7, 64% female); 472 (1.4%) incident cases of MDD were identified during the 13-year follow-up. In Cox regression analyses, higher durations of passive sedentary behavior (≥3 h/day versus <3 h/day) were associated with greater hazards of developing MDD (HR = 1.27; 95% CI = 1.01, 1.58). This relationship remained after adjusting for confounders (HR = 1.29; 95% CI = 1.03, 1.63). Adding sleep problems into the analysis significantly attenuated these relationships (HR = 1.25; 95% CI = 0.99, 1.57). The excess MDD relative risk of passive sedentary behaviors due to sleep problems was statistically significant.Limitations: Measures of sedentary behavior, physical activity and sleep were self-reported.Conclusion: Sleep problems appear to mediate detrimental associations of passive sedentary behavior with depression. Findings require further confirmation using objective measures. [ABSTRACT FROM AUTHOR]