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Background/Objective: Falls cause significant problems for older adults. Sedentary time is associated with lower physical function and could increase the risk for falls. Design: Prospective study. Setting: Sites across the United States. Participants: Older women (N = 5,545, mean age 79 years) from the Women's Health Initiative Objective Physical Activity and Cardiovascular Health study. Measurements: Accelerometers worn at the hip for up to 1 week collected measures of daily sedentary time and the mean sedentary bout duration, a commonly used metric for sedentary accumulation patterns. For up to 13 months after accelerometer wear, women reported daily whether they had fallen on monthly calendars. Results: In fully adjusted models, the incident rate ratios (95% confidence interval) for quartiles 1 (lowest), 2, 3, and 4 of sedentary time respectively were 1.0 (ref.), 1.07 (0.93–1.24), 1.07 (0.91–1.25), and 1.14 (0.96–1.35; P‐trend =.65) and for mean sedentary bout duration was 1.0 (ref.), 1.05 (0.92–1.21), 1.02 (0.88–1.17), and 1.17 (1.01–1.37; P‐trend =.01), respectively. Women with a history of two or more falls had stronger associations between sedentary time and falls incidence compared with women with a history of no or one fall (P for interaction =.046). Conclusions: Older women in the highest quartile of mean sedentary bout duration had a significantly increased risk of falling. Women with a history of frequent falling may be at higher risk for falling if they have high sedentary time. Interventions testing whether shortening total sedentary time and/or sedentary bouts lowers fall risk are needed to confirm these observational findings. [ABSTRACT FROM AUTHOR]

Background: Few studies have examined accelerometer‐measured physical activity and incident breast cancer (BC). Thus, this study examined associations between accelerometer‐measured vector magnitude counts per 15 seconds (VM/15s) and average daily minutes of light physical activity (LPA), moderate‐to‐vigorous PA (MVPA), and total PA (TPA) and BC risk among women in the Women's Health Accelerometry Collaboration (WHAC). Methods: The WHAC comprised 21,089 postmenopausal women (15,375 from the Women's Health Study [WHS]; 5714 from the Women's Health Initiative Objective Physical Activity and Cardiovascular Health Study [OPACH]). Women wore an ActiGraph GT3X+ on the hip for ≥4 days and were followed for 7.4 average years to identify physician‐adjudicated in situ (n = 94) or invasive (n = 546) BCs. Multivariable stratified Cox regression estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for tertiles of physical activity measures in association with incident BC overall and by cohort. Effect measure modification was examined by age, race/ethnicity, and body mass index (BMI). Results: In covariate‐adjusted models, the highest (vs. lowest) tertiles of VM/15s, TPA, LPA, and MVPA were associated with BC HRs of 0.80 (95% CI, 0.64–0.99), 0.84 (95% CI, 0.69–1.02), 0.89 (95% CI, 0.73–1.08), and 0.81 (95% CI, 0.64–1.01), respectively. Further adjustment for BMI or physical function attenuated these associations. Associations were more pronounced among OPACH than WHS women for VM/15s, MVPA, and TPA; younger than older women for MVPA; and women with BMI ≥30 than <30 kg/m2 for LPA. Conclusion: Greater levels of accelerometer‐assessed PA were associated with lower BC risk. Associations varied by age and obesity and were not independent of BMI or physical function. In a study of over 20,000 US postmenopausal women, higher levels of accelerometer‐measured physical activity were associated with lower risk of breast cancer. Associations varied by age and obesity and were not independent of body mass index or physical function. [ABSTRACT FROM AUTHOR]

Objectives: To prospectively examine associations between accelerometer‐measured physical activity (PA) and mortality in older women, with an emphasis on light‐intensity PA. Design: Prospective cohort study with baseline data collection between March 2012 and April 2014. Setting: Women's Health Initiative cohort in the United States. Participants: Community‐dwelling women aged 63 to 99 (N = 6,382). Measurements: Minutes per day of usual PA measured using hip‐worn triaxial accelerometers, physical functioning measured using the Short Physical Performance Battery, mortality follow‐up for a mean 3.1 years through September 2016 (450 deaths). Results: When adjusted for accelerometer wear time, age, race‐ethnicity, education, smoking, alcohol, self‐rated health, and comorbidities, relative risks (95% confidence intervals) for all‐cause mortality across PA tertiles were 1.00 (referent), 0.86 (0.69, 1.08), 0.80 (0.62, 1.03) trend P = .07, for low light; 1.00, 0.57 (0.45, 0.71), 0.47 (0.35, 0.61) trend P < .001, for high light; and, 1.00, 0.63 (0.50, 0.79), 0.42 (0.30, 0.57) trend P < .001, for moderate‐to‐vigorous PA (MVPA). Associations remained significant for high light‐intensity PA and MVPA (P < .001) after further adjustment for physical function. Each 30‐min/d increment in light‐intensity (low and high combined) PA and MVPA was associated, on average, with multivariable relative risk reductions of 12% and 39%, respectively (P < .01). After further simultaneous adjusting for light intensity and MVPA, the inverse associations remained significant (light‐intensity PA: RR = 0.93, 95% CI = 0.89–0.97; MVPA: RR = 0.67, 95% CI = 0.58–0.78). These relative risks did not differ between subgroups for age or race and ethnicity (interaction, P ≥ .14, all). Conclusion: When measured using accelerometers, light‐intensity and MVPA are associated with lower mortality in older women. These findings suggest that replacing sedentary time with light‐intensity PA is a public health strategy that could benefit an aging society and warrants further investigation. [ABSTRACT FROM AUTHOR]