Familial aggregation of blood pressure and weight in adoptive families. II. Estimation of the relative contributions of genetic and common environmental factors to blood pressure correlations between family members.

An analysis of the familial aggregation of blood pressure (BP) was conducted to provide estimates of the role of genes and household environment in determining the phenotypic resemblance between biologically related family members. The biological model used for this analysis parameterizes the correlations between family members into the contributions of genetic and environmental variability shared within and across generations. Hypothesis testing about different parameters in the model suggests that shared environment explains larger fractions of the parent-natural child and the full sib correlations for diastolic BP than for systolic BP. For diastolic BP, children in a household share the effects of common environment in addition to the effects which they share with their parents. Dependence of the degree of resemblance between household members on the effects of environmental factors shared within and a-ross generations is not explained by the variability of length of cohabitation among individuals.