Relationship between non-high-density lipoprotein cholesterol and low-density lipoprotein cholesterol in the general population: The KOBE study and Tsuruoka Metabolomic cohort study

Aim: The Japan Atherosclerosis Society (JAS) Guidelines for Diagnosis and Prevention of Atherosclerotic Cardiovascular Diseases for Japanese 2012 version have set a non-high-density lipoprotein cholesterol (non-HDL-C)-management target of low-density lipoprotein cholesterol (LDL-C) + 30 mg/ dL. However, the actual difference between non-HDL-C and LDL-C is not clear. Therefore, we evaluated its joint distribution and assessed the validity of this criterion in the general Japanese population. Methods: We used baseline cross-sectional data of 4,110 participants from two studies; the KOBE Study (n=1,108) and the Tsuruoka Metabolomic Cohort Study (n= 3,002). To evaluate whether the difference between LDL-C and non-HDL-C in the general population match that of the current guidelines, we classified LDL-C levels into four groups according to the JAS Guideline and evaluated its agreement with the corresponding non-HDL-C group. Analysis was also done using six groups (the previous four groups plus the upper and lower cut-off values). Results: The mean difference (mg/dL) between the non-HDL-C and LDL-C (for the KOBE Study and Tsuruoka Metabolomic Cohort Study, respectively) was 19.6 and 24.1 (p < 0.001) for men and 15.9 and 18.3 (p < 0.001) for women. In both the cohort studies, the difference was lower than 30 mg/dL. It was especially small among individuals with normal triglyceride levels. Conclusions: In the general Japanese population, the difference between non-HDL-C and LDL-C was lower than the expected difference of 30 mg/dL. Changes to the criteria for non-HDL-C target levels may be considered in the future.