Intrafamilial Associations of Lipids

Using the hypertriglyceridemic recall group of the Princeton School Family Study, we assessed the effectiveness and ramifications of family sampling based on hypertriglyceridemic probands and examined whether within-family correlations of lipids and lipoproteins outlast the period of shared common household environments. Thirty-two pediatric and 35 adult probands (who had fasting plasma triglyceride in the ninety-fifth percentile or above on initial sampling at visit 1) and their first-degree relatives were studied; 19 of the 32 pediatric probands (59%) had top-quartile triglyceride levels at the Family Study visit, and 14 (44%) were still in the ninety-fifth percentile triglyceride level. Twenty of 35 adult probands (57%) retained triglyceride in the ninety-fifth percentile or above at the Family Study visit, while 30 (86%) had topquartile triglyceride levels. Among the 67 probands, more subjects than expected had elevated total and low-density lipoprotein (LDL) cholesterol; probands were underand overrepresented in the top and bottom quartiles, respectively, of the high-density lipoprotein (HDL) cholesterol distribution. Twenty-one percent and 12% of the hypertriglyceridemic probands' siblings and offspring, respectively, also had triglyceride above the ageand sex-specific ninety-fifth percentile; siblings' and offspring's total and LDL cholesterol were shifted toward higher values. In adult relatives of hypertriglyceridemic probands, a parabolic relationship between triglycerides and LDL cholesterol, positive in the lowest triglyceride tertile and inverse in the top tertile, was observed. This suggests uncoupling of very low density lipoprotein-LDL precursor-product relationships in hypertriglyceridemic subjects. All lipid and lipoprotein correlations