Heredity, stress and blood pressure, a family set method—III: Family aggregation of hypertension

This third article, in a series of five, examines the role of family aggregation of hypertension. A family set sample composed of index, sib, first cousin and unrelated persons, for both black and white families, is used for this analysis. Results indicate that diastolic and systolic hypertension aggregate in family sets, but only weakly. Comparison of the observed proportions of diastolic and systolic hypertension among the relatives of hypertensive index cases with the expected proportions fails to support a dominant or recessive genetic model; a threshold model fits diastolic pressure better than systolic, which shows a poor fit, but even here discrepancies in siblings exist. Neither differences in residential environments nor race appear significant in this analysis. Results suggest that prior studies may have overestimated the genetic contribution to blood pressure, possibly by confounding of age and temporal changes.