Maximum-likelihood generalized heritability estimate for blood pressure inNigerian families

Elevated blood pressure (BP) is more common in relatives of hypertensives t han in relatives of normotensives, indicating familial resemblance of the B P phenotypes. Most published studies have been conducted in westernized soc ieties. To assess the ability to generalize these estimates, we examined fa milial patterns of BP in a population-based sample of 510 nuclear families, including 1552 individuals (320 fathers, 370 mothers, 475 sons, and 387 da ughters) from Ibadan, Nigeria. The prevalence of obesity in this community is low (body mass index: fathers, 21.6; mothers, 23.6; sons, 19.2; and daug hters=21.0 kg/m(2)). The BP phenotype used in ail analyses was created from the best regression model by standardizing the age-adjusted systolic blood pressure (SBP) and diastolic blood pressure (DBP) to 0 mean and unit varia nce. Heritability was estimated by use of the computer program SEGPATH from the most parsimonious model of "no spouse ansi neither gender nor generati on difference" as 45% for SEP and 43% for DBP. The lack of a significant sp ouse con-elation is consistent with little or no influence of the common fa milial environment. However, the heritability estimate of <50% for both SEP and DBPs reinforces the importance of the nonshared environmental effect.