Genetic-environmental interactions in the variation of blood pressure in Tecumseh, Michigan

Abstract

Emigrants and those who die were found to have higher age adjusted systolic BP than non-migrants and emigrants showed higher BP than non-migrants. For two single-locus cases, and their combined two-locus marker case, the BP differences among marker phenotypes were not homogeneous between non-migrants and those who die and between emigrants and those who die. The BP of emigrant marker phenotypes for the non-migrant-emigrant contrast varied in the same direction as the BP of marker phenotypes of those who died in the non-migrant-die contrast, but in the former contrast the marker phenotype-subsample interaction was not judged statistically significant by the available samples. This may result from the lack of specificity in the emigrant sub-sample for comparison which is presumed to have experienced high levels of stress.Our data suggests that life crises which generate stress exaggerate differences in BP between genotypes of loci which affect the level or rate of rise of BP. The average effects of both Rh-C and Kell alleles for emigrants resembled that of those who die more closely than that of non-migrants. These results are consistent with an explanation which attributes to stress encountered in life crises a major role in accounting for phenotypic differences in BP. Its effect is to raise BP in certain predisposed genotypes which are marked by dosages of the c and k alleles.