What factors are associated with physical activity in older people, assessed objectively by accelerometry?

Objectives: To assess physical activity (PA) levels measured objectively using accelerometers in community-dwelling older people and to examine the associations with health, disability, anthropometric measures and psychosocial factors. Design: Cross-sectional survey. Setting: Single general practice (primary care centre), United Kingdom. Participants: Random selection of 560 community-dwelling older people at least 65 years old, registered with the practice. 43% (238/560) participated. Assessment of risk factors: Participants completed a questionnaire assessing health, disability, psychosocial factors and PA levels; underwent anthropometric assessment; and wore an accelerometer (Actigraph) for 7 days. Main outcome measures: Average daily accelerometer step-counts and time spent in different PA levels. Associations between step-counts and other factors were examined using linear regression. Results: Average daily step-count was 6443 (95% CI 6032 to 6853). Men achieved 754 (84 to 1424) more steps daily than women. Step-count declined steadily with age. Independent predictors of average daily step-count were: age; general health; disability; diabetes; body mass index; exercise self-efficacy; and perceived exercise control. Activities associated independently with higher step-counts included number of long walks and dog-walking. Only 2.5% (6/238) of participants achieved the recommended 150 minutes weekly of at least moderate-intensity activity in >= 10 minute bouts; 62% (147/238) achieved none. Conclusions: This is the first population-based sample of older people with objective PA and anthropometric measures. PA levels in older people are well below recommended levels, emphasising the need to increase PA in this age group, particularly in those who are overweight/obese or have diabetes. The independent effects of exercise self-efficacy and exercise control on PA levels highlight their role as potential mediators for intervention studies.