Young adult cholesterol as a predictor of familial ischemic heart disease.

Family history for ischemic heart disease (IHD) was quantified from 229 questionnaires returned by the parents of young adults who had their total serum cholesterol levels determined as seventh graders in 1972-1973 and again 9 years later. The participants were divided into low- or high-cholesterol groups using quintiles. There were nonsignificant trends for higher prevalence of IHD in the families of individuals, principally the male participants, with persistently high total serum cholesterol levels; an excess of IHD in families of young adults with reduced high-density lipoprotein cholesterol (HDL); and a deficit of IHD in families of high-HDL participants. There was a significant interaction in family history scores between HDL and total cholesterol, such that there was an excess of IHD prevalence in families of individuals with high total cholesterol and low HDL levels, and significantly lower IHD prevalence in families of young adults with high total cholesterol and high HDL levels. Among individuals with low total cholesterol, lower family history scores were found in those with lower HDL levels.