Fat Intake and Risk of Skin Cancer in U.S. Adults.

Background: Fat intake has been associated with certain cancers, including colorectal, breast, and prostate cancers. However, literature on dietary fat and skin cancer has been limited.
Methods: We examined the association between fat intake and risk of skin cancer including cutaneous malignant melanoma, squamous cell carcinoma (SCC), and basal cell carcinoma (BCC) within two prospective studies: the Nurses' Health Study (NHS) and the Health Professionals Follow-up Study (HPFS). Dietary information on total, saturated, monounsaturated, polyunsaturated, omega-6, and omega-3 fat and cholesterol was repeatedly assessed generally every 4 years. Incident cases were identified by self-report. Diagnosis on melanoma and SCC was confirmed by pathologic records.
Results: A total of 794 melanoma, 2,223 SCC, and 17,556 BCC in the NHS (1984-2012) and 736 melanoma, 1,756 SCC, and 13,092 BCC in the HPFS (1986-2012) were documented. Higher polyunsaturated fat intake was associated with risk of SCC [pooled HR for highest vs. lowest quintiles, 1.16; 95% confidence interval (CI), 1.05-1.28; Ptrend=0.001] and BCC (pooled HR, 1.06; 95% CI, 1.01-1.11; Ptrend=0.01). Higher omega-6 fat intake was associated with risks of SCC, BCC, and melanoma. Omega-3 fat intake was associated with risk of BCC, but not with SCC or melanoma. No other fats were associated with melanoma risk. The associations were similar in women and men and by other skin cancer risk factors.Conclusions: Polyunsaturated fat intake was modestly associated with skin cancer risk.Impact: Further studies are needed to confirm our findings and to identify relevant biological mechanisms. Cancer Epidemiol Biomarkers Prev; 27(7); 776-82. ©2018 AACR. ©2018 American Association for Cancer Research.