This study was designed to estabilish serum LDL cholesterol(LDL-C) and HDL cholestrol(HDL-C) levels in the Korean adult population and to identify the difference in sex, age, and living place and the incidence of high risk group and the affecting factors on the serum lipid levels.

The serum LDL-C and HDL-C distribution in the normal Korean abult population were studied in 5,278 cases(males 2,802 and females 2,476) in the age groups of 3rd to 8th decade. Data were collected from 33 institutes and hospitals throughout the country during the period of June 1989 to December 1990. The serum Lipid levels were examined in the state of fasting of at least 12 hours. Total cholesterol and triglyceride levels were measured by enzymatic assays and HDL-C levels were determined by precipitation methods. The level of LDL-C was determined indirectly using the formula by Friedwald [LDL-C=total cholesterol-(HDL-C+triglyceride/5)].

The mean level of LDL-C was 112.1mg/dl. Males had 110.0mg/dl and females had 114.5mg/dl without statistical significance between gender, but levels were significantly higher in the 4th decade in males and in the 6th, 7th and 8th decade in females. The LDL-C levels rose gradually with the increase of age. The peak level of LDL-C for the males was in the 7th decade and that for the females was in the 8th decade.

The mean level of serum HDL-C was 45.1mg/dl. Males had 43.8mg/dl and females had 46.6mg/dl without statistical significance between gender, but levels were significantly higher in the 3rd, 4th, 5th and 6th decade in females. The incidence LDL-C level of ≥ 160mg/dl was 10.0%. Males had 8.2% and females had 12.1% with significantly higher incidence in females, especially in 6th decade females.

The incidence of LDL-C level of ≥ 160mg/dl of big cities was 10.7% and that of smaller cities & towns was 8.8% with significantly higher incidence in big cities. But, there was no significant difference in gender between big cities and smaller cities & towns. The incidence of LDL-C level of ≥ 160mg/dl was significantly higher in 7th decade males in big cities and that of big cities and smaller cities and smaller cities & towns was 15.9% and 5.2%, respectively.

The incidence of HDL-C level of <35mg/dl was 17.4% Males had 20.0% and females had 14.5% with significantly higher incidence in males, especially in 4th decade males. The incidence of HDL-C level of <35mg/dl of smaller cities & towns was 19.8% and that of big cities was 16.2% with significantly higher incidence in smaller cities & towms. Males in smaller cities & towns had 23.1% and males in big cities had 18.1% with statistical higher in smaller cities & towns. But, there was no significant difference in females between big cities and smaller cities & towns. The incidence of HDL-C level of <35mg/dl was significantly higher in 4th and 6th decade males in smaller cities & towns and that of smaller cities & towns and big cities was 26.8%, 25.6% and 16.2%, 17.7%, repectively.

The significantly positively related factors for serum LDL-C level were age, BMI, systolic blood pressure(SBP), location and occupation. And those for serum HDL-C level were SBP and family history and negatively related factor for HDL-C level were BMI, smoking, and exercise.

This study can provide the basic date base for prevention and management of coronary heart disease among Korean population.