Weight change in relation to mortality in middle-aged and elderly Chinese: the Singapore Chinese Health Study

Objectives To examine the association between weight change and mortality in middle-aged and elderly Chinese. Methods We used data from the Singapore Chinese Health Study among 36 338 participants aged 45 to 74 years at recruitment (1993-1998). Weight change was computed as the difference between weights at baseline and the follow-up 1 (1999-2004) surveys and classified as moderate-to-large weight loss (>= 10%), small weight loss (5.1-9.9%), stable weight (+/- 5%), small weight gain (5.1-9.9%) and moderate-to-large weight gain (>= 10%). The participants were free of cancer and cardiovascular disease (CVD) at the follow-up 1 survey and were followed for mortality through linkage with the Singapore Birth and Death Registry. Results: Until 31 December 2016, a total of 7551 deaths were identified during 517 128 person-years of follow-up (mean follow-up: 14.2 years). Compared to those with stable weight, significantly increased risk of all-cause mortality was found for participants with moderate-to-large weight loss (hazard ratio [HR]: 1.39; 95% CI: 1.30, 1.49), small loss (1.14; 1.06, 1.22), and moderate-to-large gain (1.13; 1.05, 1.22). Moderate-to-large weight loss was significantly associated with increased risk of mortality from CVD (including both ischemic heart disease and stroke) and respiratory disease, while moderate-to-large weight gain was significantly associated with CVD mortality. Associations were generally consistent in stratified analyses by sex, age groups (<60 and >= 60 years old), smoking status (never, former and current smoking), and baseline body mass index (<23 and >= 23 kg/m(2)), although significant effect modifications were found for certain strata. Conclusions Our findings showed that both moderate-to-large weight gain and loss conferred excess risk for all-cause and CVD mortality in middle-aged and elderly Chinese, with slightly higher risk for weight loss than weight gain. However, it remains to be examined in clinical trials whether maintaining stable body weight should be proposed to reduce mortality risk in middle-aged and elderly populations.