Association Between Obesity and Risk of Total and Obesity-Related Cancer in People With Incident Cardiovascular Disease.

Background: Cardiovascular disease (CVD) and cancer frequently co-occur due to shared risk factors such as obesity, which is linked to CVD and 14 cancer types. This study explores whether CVD pathophysiologies, combined with obesity, increase cancer risk, impacting clinical management.

Methods And Results: Data from the ARIC (Atherosclerosis Risk in Communities) study, spanning 28 years, were analyzed. The cohort included 5127 participants with incident CVD (myocardial infarction, stroke, heart failure, coronary heart disease), of whom 1511 developed a first primary cancer. Follow-up began at CVD diagnosis after Visit 1. Obesity was assessed using body mass index, waist circumference, and waist-to-hip ratio. Incidence rate differences between obesity groups were adjusted for age, sex, and center, whereas the obesity-cancer association was estimated using Fine-Gray regression adjusted for shared risk factors including smoking. Cancer incidence in obese individuals with CVD (body mass index: rate differences=226.6/100 000 person-years) was higher than in those with normal weight. Although obesity was not linked to overall cancer after adjusting for shared risk factors, it was nominally associated with obesity-related cancers. Specifically, women with CVD and obesity had increased obesity-related cancer risk (body mass index: hazard ratio, 1.67 [95% CI, 1.17-2.31]). No significant associations were found in men, even after excluding prostate cancer.

Conclusions: This study suggests that obesity is linked to higher obesity-related cancer risk in women with incident CVD, independent of shared risk factors. Further research is needed to eliminate residual confounding, understand sex differences, and explore how CVD pathophysiologies and obesity together influence cancer risk.