We determined the frequencies of genetic apolipoprotein E isoforms in 570 survivors of myocardial infarction, all with demonstrable coronary heart disease, as compared with 624 healthy persons. In controls, E-4/E-3 heterozygosity was associated with total cholesterol concentrations of 1985 (SD 364) mg/L and low-density lipoprotein (LDL)-cholesterol concentrations of 1306 (SD 332) mg/L. Significantly lower values, 1811 (SD 312) mg/L and 1121 (SD 274) mg/L, respectively, were observed for E-3/E-2 heterozygous persons. In survivors of myocardial infarction, the respective values were significantly higher than in controls, differing between E-4/E-3 and E-3/E-2 heterozygous patients by 233 and 220 mg/L, respectively. Moreover, E-4/E-3 heterozygosity was accompanied by earlier age of myocardial infarction (48.8 +/- 7.4 years) as compared with E-3/E-2 heterozygosity (53.4 +/- 6.9 years) and E-3/E-3 homozygosity (51.2 +/- 7.7 years). Evidently, apolipoprotein E polymorphism can contribute to total and LDL-cholesterol concentrations in serum, thereby affecting risk of coronary heart disease and myocardial infarction.