Heritability and familial aggregation of blood pressure

A number of family studies in the 1960s and 1970s showed that a familial tendency to high (or low) blood pressure is established early in life. However, it remained unclear whether shared genes or shared environment caused the blood pressure aggregation within families. Classically, special study designs such as adoption or twin studies are necessary to effectively discriminate genetic from shared environmental influences. Furthermore, estimates of the relative influence of genetic and environmental factors derived from cross-sectional studies do not provide information on underlying genetic and environmental sources of continuity and change in the development of (high) blood pressure from childhood onward. The aim of the current chapter, therefore, is to review the available literature of genetically informative epidemiologic studies to address two issues: the potential causes of familial aggregation of blood pressure and the age dependency of genetic or environmental sources of blood pressure variation (and covariation) within and between families.