Among 2,943 survivors, we observed for the first time that visceral and intramuscular adiposity are associated with an increased CVD incidence after breast cancer. Furthermore, our data highlight visceral adiposity as an occult risk factor among normal-weight patients with breast cancer, who are not typically considered to have a high CVD risk: greater visceral adiposity was associated with a 70% increased CVD risk among normal-weight women independent of cancer treatments and pre-existing risk factors such as diabetes, hypertension, or dyslipidemia.
Importance Current public health guidelines for obesity prevention and control focus on promoting a normal body mass index (BMI), rarely addressing central obesity, which is reflected by high waist circumference (WC) and common in the general population. Studies of the association of normal-weight central obesity with long-term health outcomes are sparse.
Objective To examine associations of normal-weight central obesity with all-cause and cause-specific mortality in postmenopausal women in the United States.
Design, Setting, and Participants A nationwide prospective cohort study of 156?624 postmenopausal women enrolled in the Women’s Health Initiative at 40 clinical centers in the United States between 1993 and 1998. These women were observed through February 2017. Data analysis was performed from September 15, 2017, to March 13, 2019.
Exposures Different combinations of BMI (calculated as weight in kilograms divided by height in meters squared; normal weight: BMI, 18.5-24.9; overweight: BMI, 25.0-29.9; and obesity: BMI, ≥30) and WC (normal: WC, ≤88 cm and high: WC, >88 cm).
Main Outcomes and Measures Mortality from all causes, cardiovascular disease, and cancer.
Results Of the 156?624 women (mean [SD] age, 63.2 [7.2] years), during 2?811?187 person-years of follow-up, 43?838 deaths occurred, including 12?965 deaths from cardiovascular disease (29.6%) and 11?828 deaths from cancer (27.0%). Compared with women with normal weight and no central obesity and adjusted for demographic characteristics, socioeconomic status, lifestyle factors, and hormone use, the hazard ratio for all-cause mortality was 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 with overweight and no central obesity, 1.16 (95% CI, 1.13-1.20) for women with overweight and central obesity, 0.93 (95% CI, 0.89-0.94) for women with obesity and no central obesity, and 1.30 (95% CI, 1.27-1.34) for women with obesity and central obesity. Compared with normal weight without central obesity, normal-weight central obesity was associated with higher risk of cardiovascular disease mortality (hazard ratio, 1.25; 95% CI, 1.05-1.46) and cancer mortality (hazard ratio, 1.20; 95% CI, 1.01-1.43).
Conclusions and Relevance Normal-weight central obesity in women was associated with excess risk of mortality, similar to that of women with BMI-defined obesity with central obesity. These findings underscore the need for future public health guidelines to include the prevention and control of central obesity, even in individuals with normal BMI.