Lower skin cancer risk in women with higher body mass index: The Women’s Health Initiative Observational Study

摘要

The unclear relationship of obesity to incident melanoma and nonmelanoma skin cancer (NMSC) risks was evaluated in the large, geographically diverse longitudinal, prospective Women’s Health Initiative (WHI) Observational Study. Risks of melanoma and NMSC in normal weight women were compared to risks in overweight (BMI = 25 – 29.0 kg/m²) and obese (BMI ≥ 30 kg/m²) women, using Cox proportional hazards models for melanoma and logistic regression for NMSC. Over a mean 9.4 years of follow-up, there were 386 melanoma and 9,870 NSMC cases. Risk of melanoma did not differ across weight categories (p=0.86), whereas in fully adjusted models, NMSC risk was lower in overweight (OR 0.93, 95% CI: 0.89–0.99) and obese (OR 0.85, 95% CI: 0.80–0.91) women (p<0.001). Excess body weight was not associated with melanoma risk in postmenopausal women but was inversely associated with NMSC risk, possibly due to lower sun exposure in overweight and obese women. This supports previous work demonstrating the relationship between excess body weight and skin cancer risk.