Blood pressure and its correlates in an African tribe in urban and rural environments.

Abstract

As part of a longitudinal study of migrants who move from a subsistence farming rural society to Nairobi, blood pressures and associated factors were measured in cross sectional studies of members of the Luo tribe in their traditional rural environment and in the urban environment of Nairobi. Blood pressures in Nairobi correlated with duration of urban residence. In the rural area men showed a negligible rise in blood pressure with age, and both sexes showed a significantly smaller rise than in the urban area. Although mean weights of the rural group were smaller, this did not account for all the urban/rural differences in blood pressures. Mean urinary Na concentration and Na ratios (Na/K and Na/creatinine) were significantly higher in the urban group; mean urinary K concentration and K/creatinine ratio were significantly lower. Perhaps the ratio of Na/K in the diet contributed to the different blood pressure profiles of these 2 populations.