The Relationship Between Cholesterol Level and Mortality in Korean Women

Song, Yun Mi; Sung, Joo Hon; Byeon, Jai Jun; Kim, Joung Soon; Park, Oh Young

Abstract

BACKGROUND: There were many efforts to evaluate the relationship between cholesterol and mortality. But almost all of them have been performed on male western people who have higher mean cholesterol concentration than oriental people and have different disease pattern from women's. So, upto now, the relationship of cholesterol to mortality in women with low cholesterol concentration was not well known. We carried out this study to investigate the relationship in Korea women whose mean cholesterol level was lower than that of western people and men. METHOD: Study subjects included in were 100,363 Korean women aged 30-65 years. They undertook multiphasic health examination provided by Korea Medical Insurance Corporation between March 1990 and July 1990, and had no history of cancer and no significant medical illnesses which could change blood cholesterol level. Study subjects were followed for 5.5 years until December 1995 and it was determined whether each subject was dead or alive using the mortality data from the Korea National Statistical office and the Korea Medical Insurance Corporation. Nonlinear ralationship between serum total cholesterol and mortality was investigated with the use of quadratic regression and with dummy variables using the 158-180mg/dl group as the comparison group. To analyzing the relationship between cholesterol concentra-tion and mortality with controlling for age, smoking, alcohol drinking, exercise, diastolic blood pressure, body mass index, pay level, Cox propor-tional hazard model was used. RESULT: During the follow-up period, there were 369 deaths. Mean cholesterol concentration of study subjects was 182.8mg/dl There was no significant association between serum cholesterol and total mortality, but women with cholesterol concentrations below 130mg/dl showed slightly increased risk of death(RR=1.20). Cholesterol had an inverse relationship with mortality from stroke, and women with cholesterol concentrations below 130mg/dl had higher risk of death from stroke(RR=3.28). Although there was no statistical significance,risk of mortality from hemorrhagic stroke in women with very low cholesterol concentration was markedly higher than in women with cholesterol concentrations above 130mg/dl. Mortality relationship with cholesterol. And women with cholesterol concentrations higher than 203mg/dl had abruply increased risk for death from ischemic heart disease.
CONCLUSION
Through this study, we could observe an inverse J shaped relationship between cholesterol concentration and mortality in Korean women. The increased risk of mortality from hemorrhagic stroke in people with very low cholesterol concentration supports the previous report which proposed low cholesterol level as a significant risk factor of hemorrhagic stroke. In spite of the lack of statistical signi-ficance, greately increased risk of mortality from ischemic heart disease in people with cholesterol higher than 203mg/dl suggests that cholesterol concentration at the upper end of distribution can be a significant risk factor of ischemic heart disease in women.