Statin Use and Site-Specific Cancer Risk: A Nationwide Cohort Study Using Korean Health Insurance Data.

OBJECTIVE

Statins are used for cardiovascular prevention and may exert anticancer effects by modulating the mevalonate pathway and tumor microenvironment. However, population-based evidence in Koreans remains limited. This study evaluated the association between statin use and cancer risk using Korean nationwide health data.

METHODS

This population-based cohort study used the Korean National Health Insurance Service database. Individuals who underwent health screening in 2009-2010 were followed until 2019. Statin users referred to individuals prescribed statins for ≥6 months, whereas non-users had no statin exposure. Incident cancers were identified using International Classification of Diseases, 10th Revision, codes. Multivariable Cox proportional hazards models were used to estimate adjusted hazard ratios (aHRs).

RESULTS

Among 232,133 participants (67,064 statin users, 165,069 non-users), the incidence rate for all malignancies was 10.60 per 1,000 person-years (PY) in statin users and 10.18 per 1,000 PY in non-users. After adjusting for confounders, statin use was associated with a modest but significant reduction in overall cancer risk (aHR, 0.96; 95% confidence interval [CI], 0.93-1.00; p=0.031). Site-specific analyses demonstrated reduced risk of liver cancer (aHR, 0.52; 95% CI, 0.44-0.61; p<0.001) among statin users. Conversely, thyroid cancer incidence was higher among statin users, and statin use was markedly associated with increased thyroid cancer risk (aHR, 1.19; 95% CI, 1.07-1.33; p=0.001).

CONCLUSION

In this nationwide Korean cohort, statin use was associated with a reduced risk of liver cancer but a significantly increased risk of thyroid cancer. These findings suggest organ-specific effects of statins on carcinogenesis and warrant further mechanistic investigation.