Heredity, stress and blood pressure, a family set approach: the Detroit Project revisited.

Earlier conclusions from the Detroit Project utilizing an innovative "family sets" approach indicated that unspecified environmental factors, rather than genes, are the main determinants of blood pressure variation in blacks and whites. We report new estimates of the fraction of variation in blood pressure associated with genetic differences among individuals obtained under two methodologies: the method originally proposed for family sets and a maximum likelihood method. The family sets estimates of heritability were significant for systolic and diastolic blood pressure in both blacks and whites. Estimates for both the likelihood analysis and family sets method are within the range of estimates reported in other studies. In the present study all sets collected were included, the sets were stratified only by race and a different estimate of variance for the family sets estimate of heritability was used. The discrepancies between results presented here and the original study are attributed to these three factors.