Risk of Cardiovascular Disease according to Baseline Low-Density Lipoprotein Cholesterol Level in Different Age Groups in Korean Diabetes Population: A Cohort Study

Background: The association between low-density lipoprotein (LDL-C) levels and cardiovascular disease (CVD) risk in different age groups within the diabetes mellitus (DM) population remains unclear. The cohort study was conducted to investigate this relationship.Methods: We assessed the 2009 to 2012 Korean National Health Screening and National Health Insurance Service records, with follow-up to the primary outcome (myocardial infarction MI or stroke) or December 2018. After excluding the participants with a history of MI or stroke, 2,227,394 participants with DM were included and categorized according to baseline LDL-C levels and age. Cox proportional hazards modeling was conducted. The CVD risk of age <40 years and LDL-C <70 mg/dL was set as the reference. In each age group, LDL-C <70 mg/dL was used as a reference for the subgroup analysis.Results: The cut-off LDL-C value for increased MI risk in each age group varied (<40 years old, LDL-C ≥160 mg/dL: hazard ratios HR, 2.03; 95% confidence interval CI, 1.644 to 2.506) (40–49-year-old, LDL-C <115 mg/dL: HR, 1.245; 95% CI, 1.04 to 1.489) (50–59-year-old, LDL-C <115 mg/dL: HR, 1.21; 95% CI, 1.014 to 1.445) (60-69-year-old, LDL-C <145 mg/dL: HR, 1.229; 95% CI, 1.022 to 1.479) (≥70 years old group, LDL-C <100 mg/dL: HR, 1.238; 95% CI, 1.018 to 1.504). The cut-off LDL-C values for increased stroke risk varied in each age subgroup (<40 years old, LDL-C ≥160 mg/dL: HR, 1.395; 95% CI, 1.094 to 1.779) (40–49-year-old, LDL-C <145 mg/dL: HR, 1.13; 95% CI, 1.019 to 1.253) (50–59-year-old, LDL-C <160 mg/dL: HR, 1.079; 95% CI, 1.008 to 1.154) (60–69-year-old, LDL-C <130 mg/dL: HR, 1.07; 95% CI, 1.022 to 1.119) (≥70 years old, LDL-C <115 mg/dL: HR, 1.064; 95% CI, 1.019 to 1.112).Conclusion: The effect of LDL-C on the risk of CVD differs depending on the age of the population with DM.