Weight-associated risk for developing breast cancer after menopause may be higher among women with cardiovascular disease compared with those without cardiovascular disease and women with or without type 2 diabetes, according to the results of two prospective European cohort studies, which were published in Cancer.
“The findings of this study could be used to inform risk-stratified breast cancer screening programs,” stated lead investigator Heinz Freisling, PhD, of the International Agency for Research on Cancer. “This study should also inspire future research to include women with a history of cardiovascular diseases in weight loss trials for breast cancer prevention.”
Study Methods and Key Findings
Researchers sought to assess whether the association of body mass index (BMI) with breast cancer risk differed among women with and without cardiovascular diseases or type 2 diabetes.
They collected individual participant data from the European Prospective Investigation into Cancer and Nutrition and UK Biobank data sets that included 168,547 postmenopausal women without cancer, type 2 diabetes, and cardiovascular disease at the time of recruitment and assessed incidence rates per 1,000 person-years and rate differences. After a median follow-up of more than 10 years for each data set, 6,793 postmenopausal women developed breast cancer.
In a meta-analysis of both data sets, BMI was more strongly associated with breast cancer risk among women with cardiovascular disease (hazard ratio [HR] = 1.31; 95% confidence interval [CI] = 1.16–1.47) than those without (HR = 1.13; 95% CI = 1.11– 1.16; P = .02). There were 1.53 more cases of breast cancer per 1,000 person-years in patients who had overweight or obesity and cardiovascular disease than expected.
The incidence of type 2 diabetes did not appear to modify the risk for breast cancer (P = .33), and no joint association was observed with diabetes and overweight or obesity.
Disclosure: For full disclosures of the study authors, visit onlinelibrary.wiley.com.
