Twin studies of coronary heart disease and its risk factors

Abstract

The ongoing comprehensive study of the updated population-based Norwegian Twin Panel (like-sexed twin pairs born since 1915) has already given results of interest to the research on coronary heart disease and its risk factors. Significantly more dizygotic (DZ) than monozygotic (MZ) pairs are discordant for death between 40 and 60 years of age. Presumably, several of the cases must have been coronary heart disease deaths. In pairs where both members are alive, concordance rate for coronary heart disease before the age of 60 years is significantly higher in MZ than in DZ pairs. Concordance rate for reported hypertension is significantly higher in MZ than in DZ pairs. These findings are compatible with a significant genetic effect on premature death, coronary heart disease and hypertension. There is a strong genetic effect on serum level of apoB, apoA-I and apoA-II, a weaker effect on cholesterol level and a doubtful effect on triglyceride level. Genes belonging to several normal genetic polymorphisms may participate in the control of environmentally/dietary caused variability in lipid and lipoprotein parameters. The study of MZ twins that was conducted to detect these effects holds considerable promise for the detection of gene control of may kinds of quantitative parameters.