Serum cholesterol distribution and coronary heart disease risk: observations and predictions among middle-aged population in eastern Finland

The purpose of the present study was to assess the implications of cholesterol distribution and its change on coronary heart disease (CHD) mortality and disease prevention at a population level.

In five independent risk factor surveys (1972, 1977, 1982, 1987, and 1992) in eastern Finland, serum cholesterol was measured in 27721 randomly selected men and women aged 30 to 59 years. The association between cholesterol level and CHD risk and the prediction of the effect of different prevention strategies was estimated by use of logistic regression models. The entire cholesterol distribution of the population shifted markedly toward lower levels between 1972 and 1992. The proportion of subjects with a very high cholesterol level (> or =8.0 mmol/L), also decreased markedly, from 16% to 3%. The risk of CHD death among subjects with cholesterol > or =8.0 mmol/L was approximately 5-fold that of those individuals having cholesterol <5.0 mmol/L. Nevertheless, because CHD risk increases continuously as serum cholesterol increases, and because the number of people having only slightly or moderately increased serum cholesterol was large, most CHD deaths occurred among them. A 10% reduction in cholesterol levels in the entire population would subsequently reduce CHD mortality by 20%, as much as an effective treatment as a 25% decrease in serum cholesterol among all subjects with cholesterol >6.5 mmol/L and four times more than similar treatment of all subjects with cholesterol > or =8.0 mmol/L.

The community-based population strategy in cardiovascular disease prevention was effective in decreasing cholesterol levels among the entire population, including the subjects with the highest cholesterol values. The balanced application of both high-risk and population strategies is needed for the effective prevention of CHD.