Apo(a) Phenotypes and Lp(a) Concentrations in Offspring of Men With and Without Myocardial Infarction

Abstract

Abstract In the European Atherosclerosis Research Study, genetic and environmental markers of risk of premature coronary heart disease were compared in offspring of men with and without myocardial infarction before the age of 55 years. Cases were 682 students with a paternal history of myocardial infarction, and control subjects were 1312 students without such a history. The students were enrolled in 14 universities in five European regions (Finland, Great Britain, and northern, middle, and southern Europe). Lipoprotein(a) [Lp(a)] concentrations were skewed towards lower concentrations in both cases (median, 7.3 mg/dL; 95% confidence interval, 6.3 to 8.1 mg/dL) and control subjects (median, 6.6 mg/dL; 95% confidence interval, 6.1 to 7.2 mg/dL) ( P =.37). Significantly more northern European male cases than control subjects had Lp(a) levels exceeding 30 mg/dL ( P =.040), but this did not pertain to females ( P =.29), and overall, there was no difference between cases (16.5%) and control subjects (15.5%) in the frequency of Lp(a) concentrations above 30 mg/dL ( P =.63). As expected, there was a significant ( P <.01) inverse relationship between apo(a) molecular size and Lp(a) concentration. In Great Britain there was a significant difference in phenotype distribution between cases and control subjects ( P =.035), due mainly to a high frequency of the apo(a) S2 isoform in cases. A similar but statistically insignificant tendency was seen in northern Europeans. In the three other regions, however, the distribution of apo(a) phenotypes among cases and controls was similar, and in the study population overall, the distribution of apo(a) phenotypes did not differ significantly ( P =.74) between cases and control subjects.