Longitudinal changes in body mass index and body composition over 3 years and relationship to health outcomes in Hong Kong Chinese age 70 and older

OBJECTIVES: To determine longitudinal changes in body mass index (BMI) and body composition with age and the relationship between these changes with m ortality, morbidity, functional capacity, and other health outcome measures . DESIGN: A S-year longitudinal study of a random sample of community-living subjects. SETTING: Older Chinese in the Hong Kong Special Administrative Region of Ch ina. PARTICIPANTS: TWO thousand and thirty-two Chinese subjects age 70 and older recruited territory-wide by proportional random sampling. MEASUREMENTS: Baseline information collected included medical history, self -perceived health, Barthel Index, Geriatric Depression Score, time taken to complete a 16-foot walk, height, weight, mid-arm circumference, arm skin-f old thickness, and waist/hip ratio. Body composition was calculated from pr ediction equation. Outcome measures included mortality, development of new diseases, Barthel Index, time taken for 16-foot walk, self-perceived health , and Geriatric Depression Score. RESULTS: All parameters, with the exception of triceps skin-fold thickness in men, decreased, regardless of presence or absence of disease. The decrea se in arm circumference, triceps skin-fold thickness, and total body fat (T BF) was greater in women than in men, whereas men had a greater decrease in fat-free mass (FFM). Even in the absence of disease, three times as many s ubjects lost greater than or equal to 5kg in weight as gained greater than or equal to 5kg (15% vs 5%), and only age could be identified as a contribu ting factor to this weight loss. In the absence of disease, lower anthropom etric indices were associated with greater mortality, development of new di s ease (in women only), dependency, and poor performance measure. Waist-hip ratio was not associated with mortality or any other health outcomes. Decr ease in both FFM and TBF were associated with worse outcomes, the effect be ing more marked in women. CONCLUSION: In the older population, changes in weight and body composition occur even in the absence of disease and are associated with mortality and physical functioning level. Weight loss rather than weight gain appears to be more important in this population, and promotion of life-style interven tions targeted at weight maintenance would be important.