[Genetic analysis of the structure of the predisposition to ischemic heart disease].

Clinical and ECG examination of 752 male population samples (598 Uzbeks and 154 Russians) aged from 40 to 74 conducted according to the WHO criteria showed the incidence of ischemic heart disease among males 40 to 59 years of age to be 10.7% for Uzbeks and 15.1% for Russians (p greater than 0.3) and among males aged from 60 to 74, 16.8 and 19.7%, respectively. The incidence of ischemic heart disease was lower among brothers of male probands 40 to 74 years of age (33.9%) than among brothers of female probands (38.9%); the incidence of this disease was lower among sisters of male probands (23.1%) than among sisters of female probands (30.2%). A similar peculiarity of ischemic heart disease distribution among siblings according to the sex of their probands was found in the 40- to 59-year-old group. This indicates the existence of two thresholds which determine ischemic heart disease prevalence among the different sexes of the population. The incidence of ischemic heart disease among the spouses of the probands aged from 40 to 74 is also higher than that among the population in general; it was 17% on the average, 14.3% among female spouses and 22% among male spouses. The genetic component of ischemic heart disease determination (heritability) was approximately 60%, the intrafamilial one was approximately 20--30%. Thus, besides the genetic factors which determine the liability to ischemic heart disease, there are intrafamilial factors which have an essential effect and which also cause familial aggregation of the disease.