Obesity and risk of breast cancer mortality in Hispanic and Non-Hispanic white women: the New Mexico Women's Health Study.

Obesity is reported to be associated with poorer survival in women with breast cancer, regardless of menopausal status. Our purpose was to determine if the associations of obesity with breast cancer-specific, all-cause, and non-breast cancer mortality differ between Hispanic and non-Hispanic white (NHW) women with breast cancer. Data on lifestyle and medical history were collected for incident primary breast cancer cases (298 NHW, 279 Hispanic) in the New Mexico Women's Health Study. Mortality was ascertained through the National Death Index and New Mexico Tumor Registry over 13 years of follow-up. Adjusted Cox regression models indicated a trend towards increased risk for breast cancer-specific mortality in obese NHW women (hazard ratio [HR] 2.07; 95% confidence interval [CI] 0.98-4.35) but not in Hispanic women (HR 1.32; 95% CI 0.64-2.74). Obese NHW women had a statistically significant increased risk for all-cause mortality (HR 2.12; 95% CI 1.15-3.90) while Hispanic women did not (HR 1.23; 95% CI 0.71-2.12). Results were similar for non-breast cancer mortality: NHW (HR 2.65; 95% CI 0.90-7.81); Hispanic (HR 2.18; 95% CI 0.77-6.10). Our results suggest that obesity is associated with increased risk for breast cancer-specific mortality in NHW women; however, this association is attenuated in Hispanic women.