The aim of this study was to evaluate the relationship between the serum levels of lipoprotein (a) [Lp (a)] and apolipoproteins (apo A-1 and apo B) in schoolchildren with a history of coronary and cerebrovascular events in their grandparents. We measured serum concentrations of Lp (a) and apoliproteins immunochemically in 289 schoolchildren aged 12-13 years and questioned parents about coronary and cerebrovascular events in the children's grandparents. In boys and girls, mean +/- s.d. levels of apo A-1, apo B and Lp (a) were 134 +/- 20.3 and 136 +/- 17.4 mg/dL, 61 +/- 16 and 66 +/- 15 mg/dL and 12.5 +/- 15.3 and 12.5 +/- 15.1 mg/dL, respectively. There were no significant sex differences in the levels of apo A-1, apo B, and Lp (a). The Lp (a) levels (mean +/- s.d., 12.5 +/- 15.2 mg/dL; median 7.5 mg/dL, n = 289) were not affected by other variables. The Lp (a) distribution was strongly positively skewed and 75% of schoolchildren had very low levels. In the total 289 schoolchildren, thirty-two grandparents who had had coronary vascular events (21 myocardial infarction, 11 angina pectoris) and twenty-three grandparents who had had cerebrovascular events were recorded. By the boxplot statistical analysis, no difference was found in Lp (a) levels in children whose grandparents had myocardial infarction compared with those whose grandparents had no such history, or compared with those whose grandparents had suffered cerebrovascular events.(ABSTRACT TRUNCATED AT 250 WORDS)