Risk factor change in older persons, a perspective from Hong Kong: weight change and mortality

The influence of anthropometric measurements on mortality and longevity has been of interest to a number of investigators. However, although such measurements are not stable over time, few studies have attempted to account for such changes in longitudinal studies. The present study attempts to examine the relationship between weight change and mortality outcome.

The research was based on a longitudinal study of a cohort of 1,056 Hong Kong Chinese men and women aged 70 and above. Among the 476 nonsmoking women at baseline, 374 with weight measurements both at baseline and at 24 months follow-up were included in the study. Proportional hazards analysis with adjustments for age and other physical and social factors was used to estimate the relative risk of mortality of the higher body mass index groups in relation to the lowest body mass index group and between the weight change groups.

Women belonging to the middle tertile of body mass index distribution had the lowest mortality. Those with a weight loss of more than 2 kg over the first 24 months follow-up had five times the risk of mortality at 40 months, even after adjusting for health and social conditions and baseline body mass index.

The results suggest that both the initial body weight and weight change during the follow-up period are important considerations in the study of the association between body weight and mortality.