Central obesity is associated with an increased risk for mortality in women, according to study results published in JAMA Network Open.
The results indicated that the increased risk existed in women classified as normal weight, overweight, and obese according to BMI.
The study used data from postmenopausal women enrolled in the Women’s Health Initiative at 40 clinical centers in the United States between 1993 and 1998 (n=156,624). Patients were observed through February 2017.
The researchers measured participants’ height, weight, and waist circumference (WC) at baseline. They classified BMI as normal weight (18.5-24.9 kg/m2), overweight (25.0-29.9 kg/m2), and obese (≥30.0 kg/m2). They defined central obesity as WC >88 cm. Patients were categorized into 6 groups of obesity patterns based on the combination of BMI and WC. The primary outcomes were mortality from all causes, cardiovascular disease, and cancer.
Over 2,811,187 person-years of follow-up, there were 43,838 deaths, including 29.6% (n=12,965) from cardiovascular disease and 27.0% (n=11,828) from cancer.
After adjusting for demographic characteristics, socioeconomic status, lifestyle factors, and hormone use, the results indicated that compared with women with normal weight and no central obesity, the hazard ratios (HRs) for all-cause mortality were 1.31 (95% CI, 1.20-1.42) among women with normal weight and central obesity, 0.91 (95% CI, 0.89-0.94) among women who were overweight with no central obesity, 1.16 (95% CI, 1.13-1.20) among women who were overweight with central obesity, 0.93 (95% CI, 0.87-0.99) among women with obesity and no central obesity, and 1.30 (95% CI, 1.27-1.34) among women with obesity and central obesity.
The researchers also found that compared with women with normal weight without central obesity, women with normal weight and central obesity were at higher risk for cardiovascular disease mortality (HR, 1.24; 95% CI, 1.05-1.46) and cancer mortality (HR, 1.20; 95% CI, 1.01-1.43).
“It is notable that women with normal-weight central obesity had a similar risk as women with obesity and central obesity,” said the researchers.
“Our results highlight the inability of BMI alone to distinguish body shape or body fat distribution, the misclassification of risk because of adiposity that occurs when using BMI as a proxy for fat mass, and the importance of measuring central obesity even among people with normal weight,” they concluded.
Sun Y, Liu B, Snetselaar LG, et al. Association of normal-weight central obesity with all-cause and cause-specific mortality among postmenopausal women. JAMA Netw Open. 2019;2(7):e197337.