Renal microvascular features of hypertension in Japan, Guatemala, and the United States.

The finding of benign arteriolar nephrosclerosis at autopsy usually implies the prior existence of essential hypertension. It was found in this study that minor degrees of incipient nephrosclerosis in young people can be shown to correlate with seemingly trivial blood pressure elevations. In this study, autopsy tissues were used to assess the magnitude of early nephrosclerosis in five population groupings. A comparison of males in Tokyo, Japan, Guatemala, and New Orleans, La (blacks and whites); and females in Tokyo revealed significant differences among these populations. Blacks exceeded whites in New Orleans in the magnitude of incipient nephrosclerosis in all 10-year age groups from 15 through 24 years to 45 through 54 years. Guatemalan males were, on average, less affected than New Orleans whites in all age groups. The data for all males (age range, 15 through 54 years) in Tokyo revealed little difference in nephrosclerosis from those in New Orleans whites. Blood pressure data were obtained from reports of cross-sectional surveys in these five populations. Blood pressure in males varied across age x race subgroups in close parallel with nephrosclerosis (r = .90), implying that variation in blood pressure among groups of subjects is strongly nephrosclerosis linked, even at very young ages; findings for Tokyo females were aberrant in this correlation. The results suggest that the lifelong progression toward the hypertensive state begins in childhood, and that these beginnings are measurably in the population averages of both nephrosclerosis and blood pressure elevations. Moreover, population differences in these two commensurate measures of the early precursors of hypertension were found to be well established by the ages of 15 through 24 years and were sustained at least into the ages of 45 through 54 years. The years of adolescence are here brought under suspicion of special importance in setting the lifelong course toward the hypertensive state.