摘要：Objectives. We examined the relation between body mass index, exercise, overall health, and physical functioning. Methods. We studied 7867 adults aged 51 to 61 years in 1992 to 1996. Adjusted relative risks for health decline and new physical difficulties were determined with logistic regression. Results. Overweight and obesity were independently associated with health decline (adjusted relative risk [ARR] = 1.29 and 1.36) and development of a new physical difficulty (ARR = 1.27 and 1.45). Regular exercise significantly reduced the risk of health decline and development of a new physical difficulty, even among obese individuals. Conclusions. Maintaining ideal body weight is important in preventing decline in overall health and physical functioning. However, regular exercise can reduce the risk of health decline even among individuals who cannot achieve ideal weight. Previous studies have linked obesity with cardiovascular outcomes, 1 life expectancy, 2 mortality, 3, 4 and the risk of cancer. 5– 7 Population studies and short-term trials have shown that physical activity is associated with reductions in coronary heart disease risk 8, 9 and improvement in cardiorespiratory fitness and physical performance. 10, 11 However, there have been few large longitudinal studies investigating the relationship between body mass index (BMI), physical activity, and the risk of decline in overall health and physical functioning. 12, 13 Vita and colleagues showed that smoking, BMI, and physical activity patterns in midlife and late adulthood predicted development of disability among a group of university alumni. 12 However, these 3 risk factors were combined into a single risk index in multivariate analyses, so the independent effects of each are unclear. Moreover, it is not known whether regular exercise can ameliorate the adverse effects of obesity on health. Using data from the Health and Retirement Study (HRS), we examined the relation between BMI, physical activity, and the risk of a decline in self-reported overall health and physical functioning over 4 years among a national sample of US adults aged 51 to 61 years in 1992.
