Background: Limited information is available on the potential link between obesity and either melanoma or non-melanoma skin cancers.
Objective: To conduct a prospective study to examine the association between obesity and the risk of both melanoma and non-melanoma skin cancers.
Methods: Using pooled data from two large national cohorts in the US, the Nurses' Health Study (NHS) and the Health Professionals Follow-up Study (HPFS), we prospectively examined the incidence of melanoma, squamous cell carcinoma (SCC), and basal cell carcinoma (BCC) among participants grouped according to body mass index (BMI).
Results: Compared to participants with an updated BMI in the normal range, those with a BMI in the obese range had a 32 % lower risk of developing SCC, and those with a BMI in the morbidly obese category had a 37 % lower risk of developing SCC. The decrease in SCC risk was limited to women. Compared to participants with a BMI in the normal range, those with a BMI in the obese range had a 19 % lower risk of developing BCC, and those with a BMI in the morbidly obese category had a 29 % lower risk of developing BCC. The risk of developing melanoma did not statistically differ by BMI grouping. The results were similar using BMI measurements obtained 10 years prior to the diagnosis of skin cancer.
Conclusion: Obesity appears to be inversely associated with the development of non-melanoma skin cancers. Obesity is most likely a surrogate marker for lack of chronic sun exposure, which is a risk factor for non-melanoma skin cancers.