Relation of statin use with non-melanoma skin cancer: prospective results from the Women's Health Initiative

BACKGROUND: The relationship between statin use and non-melanoma skin cancer (NMSC) is unclear with conflicting findings in literature. Data from the Women's Health Initiative (WHI) Observational Study and WHI Clinical Trial were used to investigate the prospective relationship between statin use and NMSC in non-Hispanic white (NHW) postmenopausal women. METHODS: The WHI study enrolled women aged 50–79 years at 40 US centres. Among 133 541 NHW participants, 118 357 with no cancer history at baseline and complete medication/covariate data comprised the analytic cohort. The association of statin use (baseline, overall as a time-varying variable, duration, type, potency, lipophilicity) and NMSC incidence was determined using random-effects logistic regression models. RESULTS: Over a mean of 10.5 years of follow-up, we identified 11 555 NMSC cases. Compared with participants with no statin use, use of any statin at baseline was associated with significantly increased NMSC incidence (adjusted odds ratio (OR(adj)) 1.21; 95% confidence interval (CI): 1.07–1.35)). In particular, lovastatin (OR 1.52; 95% CI: 1.08–2.16), simvastatin (OR 1.38; 95% CI: 1.12–1.69), and lipophilic statins (OR 1.39; 95% CI: 1.18–1.64) were associated with higher NMSC risk. Low and high, but not medium, potency statins were associated with higher NMSC risk. No significant effect modification of the statin–NMSC relationship was found for age, BMI, smoking, solar irradiation, vitamin D use, and skin cancer history. CONCLUSIONS: Use of statins, particularly lipophilic statins, was associated with increased NMSC risk in postmenopausal white women in the WHI cohort. The lack of duration–effect relationship points to possible residual confounding. Additional prospective research should further investigate this relationship.