Abdominal adiposity and mortality in Chinese women

Abstract

Background: Increased abdominal adiposity has been linked to an increase in mortality in populations where many are overweight or obese; it is unclear whether the same is true in relatively lean populations.

Methods: We examined the association between waist-hip ratio and mortality in the Shanghai Women's Health Study, a population-based, prospective cohort study of Chinese women aged 40 to 70 years enrolled from December 28, 1996, through May 23, 2000, 95% of whom had a body mass index (calculated as weight in kilograms divided by height in meters squared) of less than 30.0. Included in this analysis were 72 773 nonsmoking women who had anthropometrics taken by trained interviewers at enrollment and who were followed up through December 31, 2004. Deaths were ascertained by biennial home visits and linkage with the vital statistics registry.

Results: During a mean follow-up of 5.7 years, 1456 deaths occurred. The waist-hip ratio was positively and significantly associated with deaths from all causes, cardiovascular disease, and diabetes (P<.01 for trend). A less significant positive association was found for death from cancer. After adjustment for body mass index and other potential confounders, the relative risks of total mortality were 1 (reference group), 1.28 (95% confidence interval [CI], 1.04-1.58), 1.40 (95% CI, 1.14-1.72), 1.54 (95% CI, 1.26-1.88), and 1.95 (95% CI, 1.60-2.38) across the lowest to the highest waist-hip ratio quintiles. The positive association appeared to be more evident in women with a lower body mass index. The relative risks of total mortality comparing the extreme waist-hip ratio quintiles were 2.36 (95% CI, 1.71-3.27), 1.60 (95% CI, 1.10-2.34), and 1.46 (95% CI, 0.97-2.20) for women with a body mass index of less than 22.3, 22.3 to 25.1, and 25.2 or greater, respectively.

Conclusion: Abdominal adiposity independently predicts mortality risk, particularly for nonobese women.