Strength, physical activity, and body mass index: Relationship to performance-based measures and activities of daily living among older Japanese women in Hawaii

OBJECTIVES: Remaining strong, lean, and physically active may contribute to successful aging, both by maintaining function and by enabling more independent living. The study objective was to investigate this hypothesis among a long-lived population of older Japanese women. DESIGN: A cross-sectional study. SETTING: The island of Oahu, Hawaii. PARTICIPANTS: A total of 705 community-dwelling women (mean age, 74; range, 55-93). MEASUREMENTS: As outcomes, 7 physical performance measures including walking speed, the Get Up and Go test, chair stands, functional reach, and hand and foot reaction times, and 8 questions regarding activities of daily living (ADL). As possible predictors, physical activity, body mass index, and quadriceps, grip, and triceps strength. RESULTS: In multivariable models, one or more of the strength tests was associated positively with six of the seven performance-based measures. Among the significant associations, 1-SD increases in strength were associated with 2 to 4% increases in performance compared with the sample mean. Physical activity was independently, and positively associated with the most complex of the tests, the Get Up and Go test. Body mass index (BMI), in contrast to strength and physical activity, was negatively associated with five of the seven performance tests. Among the significant associations, 1-SD increases in BMI were associated with 3 to 8% reductions in performance. In multivariable models strength was also associated positively with seven of the eight ADLs. In the same models, physical activity was positively associated with five and BMI was negatively associated with six of the ADLs. CONCLUSION: The results suggest that remaining strong, lean, and physically active provided wide-ranging benefits for this population of older Japanese women.