TRENDS IN CARDIOVASCULAR-DISEASE RISK FACTOR CLUSTERING IN EASTERN FINLAND - RESULTS OF 15-YEAR FOLLOW-UP OF THE NORTH KARELIA PROJECT

Background. The study describes 15-year cardiovascular disease risk factor clustering trends in eastern Finland and assesses the degree to which high levels of the risk factors are clustering in the same individuals. Methods. Four independent cross-sectional surveys in randomly selected population samples (in 1972, 1977, 1982, and 1987) have been carried out in two provinces in eastern Finland (North Karelia and Kuopio) to assess the level of cardiovascular disease risk factors and the impact of a community-based prevention program. Each survey included a self-administered questionnaire, blood pressure measurements, and determination of serum cholesterol. Blood pressure and serum cholesterol values were dichotomized. All subjects were classified as either current smokers or nonsmokers. The total sample size was 30,118 and the participation rate varied between 77 and 94%. The common age range in all four surveys was 30 to 59 years. Results. The proportion of individuals with a combination of two or three risk factors decreased markedly during the survey period. However, smoking tended to cluster increasingly with the other risk factors in 1987 compared with that seen in 1972. Among men, the proportion of smokers having either high blood pressure or high serum cholesterol levels, or both, is still high. Conclusions. The observed clustering of cardiovascular disease risk factors, particularly among men, underlines the importance of assessing other risk factors in persons with a high level of one risk factor and the need for a multifactorial approach in primary prevention. It is possible that high-risk behaviors, like smoking and high consumption of saturated fat and salt, were normal in 1972, but in 1987 they were declining, though they remained clustered among a particular segment of the population. (C) 1994 Academic Press, Inc.