THE SERUM ANGIOTENSINOGEN CONCENTRATION AND VARIANTS OF THE ANGIOTENSINOGEN GENE IN WHITE AND BLACK-CHILDREN

The T235 allele of the angiotensinogen gene (AGT) has been associated with hypertension. Blood pressure increases faster over time in black children than in white children, and in adults hypertension is more pr evalent in blacks. We sought evidence for a role for angiotensinogen t o contribute to racial differences in blood pressure in a study of 148 white and 62 black normotensive children (mean age, 14.8 yr). The fre quency of the T235 allele was 0.81 in blacks and 0.42 in whites (chi(2 ) = 77.3, P = 0.0001). The mean angiotensinogen level was 19% higher i n blacks than in whites (P = 0.0001 for males, P = 0.004 for females). Genotype was positively related to serum angiotensinogen in white chi ldren (P = 0.0001 for males, P = 0.004 for females), but a similar rel ationship was absent in blacks where the frequency of M235 may have be en too low to discern an association. Longitudinal blood pressure (mea sured twice yearly) adjusted for body mass index showed a marginally s ignificant relationship to the angiotensinogen level (P = 0.07). An in dependent relationship of serum angiotensinogen with body mass index ( P = 0.0001) and race (P = 0.0003) was also observed. In summary, T235 was more frequent, and the level of angiotensinogen was higher in blac ks than in whites. Such a racial difference in the renin-angiotensin s ystem may contribute to the disparity in blood pressure levels of whit e and black young people.