The relationship among physical activity, obesity, and physical function in community-dwelling older women.

BACKGROUND: The relationship between obesity and physical function is not well understood. Physical activity may be a key factor impacting on the relationship between obesity and physical function.

METHODS: Subjects included 171 community-dwelling women (mean age = 74.3, SD = 4.3) participating in a 14-year follow-up study to a walking intervention trial. Measures of obesity [body mass index (BMI)] and physical activity (Modified Paffenbarger Questionnaire) were collected in 1982, 1985, 1995, and 1999. Physical function was assessed in 1999 using the Functional Status Questionnaire (FSQ) and gait speed.

RESULTS: Measures of obesity from 1982 to 1995 and measures of physical activity from 1982 to 1995 were related to physical function in 1999. However, hierarchical regression analysis to predict physical function in 1999 controlling for the presence of chronic conditions indicated that physical activity from 1982 to 1995, and not obesity from 1982 to 1995, was an independent predictor of physical function (FSQ: adjusted R2 = 0.09, F = 4.68, P < 0.001; gait speed: adjusted R2 = 18.0, F = 9.41, P < 0.0001.

CONCLUSION: Physical activity appears to be as important if not more important than body weight in predicting future physical function.