Low-Density Lipoprotein Cholesterol Level, Statin Use and Myocardial Infarction Risk in Young Adults

Objective: The consequences of blood lipid abnormalities for cardiovascular disease risk in young adults is unclear. Optimal lipid levels may also vary depending on whether a statin drug is taken. It aimed to determine whether the optimal lipid levels in young adults differ depending on statin use. Methods: Using a nationally representative database from the Korean National Health Insurance System, 6,350,400 participants aged 20-39 years who underwent a health examination between 2009-2012 were followed through to 2018. The primary outcome was incident myocardial infarction (MI). We assessed the associations between prespecified lipid levels and MI risk according to statin use. Results: Among participants not taking statins, low-density lipoprotein cholesterol (LDL-C) levels ≥120 mg/dL were significantly associated with MI risk (hazard ratio HR, 1.33; 95% confidence interval CI, 1.27-1.40) compared with statin nonusers with LDL-C <80 mg/dL. Statin users with LDL-C categories <80, 80-100, 100-120, and ≥120 mg/dL all had significantly higher MI risk compared with statin nonusers with LDL-C <80 mg/dL; these HRs (95% CIs) were 1.66 (1.39-1.99), 1.68 (1.36-2.09), 1.63 (1.31-2.02), and 2.32 (2.07-2.60), respectively. Conclusion: Young adults taking statins have an increased MI risk compared with statin nonusers, even when they have similar LDL-C levels. Specific lipid targets may need to differ depending on statin use.