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ARS Home » Northeast Area » Boston, Massachusetts » Jean Mayer Human Nutrition Research Center On Aging » Research » Publications at this Location » Publication #331263
Title: Analysis and interpretation of accelerometry data in older adults: The LIFE Study

Author
item REJESKI, W JACK - Wake Forest University
item MARSH, ANTHONY - Wake Forest University
item BRUBAKER, PETER - Wake Forest University
item BUMAN, MATTHEW - Arizona State University
item FIELDING, ROGER - Jean Mayer Human Nutrition Research Center On Aging At Tufts University
item HIRE, DON - Wake Forest School Of Medicine
item MANINI, TODD - University Of Florida
item REGO, ALVITO - Northwestern University
item MILLER, MICHAEL - Wake Forest School Of Medicine

Submitted to: Journal of Gerontology Medical Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/9/2015
Publication Date: 10/29/2015
Citation: Rejeski, W., Marsh, A., Brubaker, P.H., Buman, M., Fielding, R.A., Hire, D., Manini, T., Rego, A., Miller, M. 2015. Analysis and interpretation of accelerometry data in older adults: The LIFE Study. Journal of Gerontology Medical Science. 71(4):521-528. doi: 10.1093/gerona/glv204.

Interpretive Summary: This study evaluated different methods to calculate participation in physical activity from older adults using a wearable monitor (Actigraph accelerometer). Older adults enrolled in the Lifestyle Interventions for Elders (LIFE) study wore a small monitor on their waist for seven days at baseline and 6 months. We found that activity counts from the monitors varied more than expected from older adults. We developed a prediction equation using age and each subjects walking speed that explained a majority of the variability in activity. This prediction equation is the first attempt to tailor specific cutpoints for physical activity in older adults. The findings of this study have important implications for the use and interpretation of accelerometry data and in the design/delivery of physical activity interventions with older adults.

Technical Abstract: BACKGROUND: Accelerometry has become the gold standard for evaluating physical activity in the health sciences. An important feature of using this technology is the cutpoint for determining moderate to vigorous physical activity (MVPA) because this is a key component of exercise prescription. This article focused on evaluating what cutpoint is appropriate for use with older adults 70-89 years who are physically compromised. METHODS: The analyses are based on data collected from the Lifestyle Interventions and Independence for Elders (LIFE) study. Accelerometry data were collected during a 40-minute, overground, walking exercise session in a subset of participants at four sites; we also used 1-week baseline and 6-month accelerometry data collected in the main trial. RESULTS: There was extreme variability in median counts per minute (CPM) achieved during a controlled bout of exercise (n = 140; median = 1,220 CPM (25th, 75th percentile = 715, 1,930 CPM). An equation combining age, age2, and 400 m gait speed explained 61% of the variance in CPM achieved during this session. When applied to the LIFE accelerometry data (n = 1,448), the use of an individually tailored cutpoint based on this equation resulted in markedly different patterns of MVPA as compared with using standard fixed cutpoints. CONCLUSIONS: The findings of this study have important implications for the use and interpretations of accelerometry data and in the design/delivery of physical activity interventions with older adults.