Statin use and site-specific risk of colorectal cancer in individuals with hypercholesterolemia from the National Health Insurance Service-National Health Screening Cohort (NHIS-HEALS)

Background and aims: We investigated the association between statin use and site-specific risk of colorectal cancer in individuals with hypercholesterolemia. Methods and results: This study is based on the National Health Insurance Service-National Health Screening Cohort, conducted during 2002–2015. Statin users were classified as high and low users according to medication possession ratio (MPR). Statin nonusers comprised participants who did not use statins during the entire follow-up period. In total, 17,737 statin users and 13,412 statin nonusers were included in the analysis, with a median follow-up period of 12.7 years. Cox proportional hazards regression models were adopted after stepwise adjustment for confounders to investigate prospective association between statin usage and colorectal cancer risk. In total, 378 (2.3%) of 16,588 male participants and 239 (1.6%) of 14,561 female participants had colorectal cancer during the follow-up period. Compared to nonusers, fully adjusted hazard ratios (HRs) (95% confidence intervals [95% CIs]) for colorectal cancer risk in high statin users were 0.56 (0.42–0.75) in men and 0.64 (0.46–0.90) in women. In men, the fully adjusted HRs for proximal and rectal cancer for high users were 0.29 (0.15–0.56) and 0.52 (0.35–0.78), respectively, compared to those for nonusers. In women, statistical significance was seen only in rectal cancer (HR 0.43 [0.25–0.72]) but not in proximal or distal colon cancer. Conclusions: High statin users with hypercholesterolemia were associated with lower risk of overall colorectal cancer, especially proximal colon cancer in men and rectal cancer in both sexes.