HDL cholesterol levels in patients with myocardial infarction and their families.

The present study using a quartile distribution of myocardial infarction patients demonstrated that the first-degree relatives of the myocardial infarction patients with the lowest HDL cholesterol have similarly the lowest HDL cholesterol. Low HDL cholesterol among these relatives was not secondary to increased VLDL triglycerides, as it persisted when subjects with hyper VLDL triglycerides were excluded. Familial low HDL cholesterol could not be attributed to known environmental factors as their levels did not differ significantly between the groups compaired. There was a significant correlation between HDL cholesterol levels of the parents and that of their younger offspring. The correlation was not significant with the offspring aged 20 and over. It appeared that there was a familial trend in low HDL cholesterol levels, more apparent among the young offspring than among the adult offspring, who may possibly not share any more the parental environment for factors liable to influence HDL cholesterol. This finding is compatible with a hereditary trait.