Familial aggregation of body mass index in ethnically diverse families in Jerusalem. The Jerusalem Lipid Research Clinic

Familial aggregation of body mass index in different ethnic populations was studied in a sample of nearly 4000 families resident in Jerusalem. Covariate adjustments were applied to body mass index (BMI) to adjust for variation in means and variances with sex, age and origin and for the effect of education, socioeconomic status and seasonality. The analyses were done separately in each of the origin groups categorized according to the parents' country of birth (Europe, Asia, North Africa, Israel/mixed origin), in order to account for the heterogeneity among the groups. Parent-child correlations were generally homogeneous across the origin groups. Sibling correlations for BMI differed to a greater extent among the groups. The highest correlation was observed in the Asian group (r = 0.49) and the lowest in the North African group (r = 0.16). Pooled correlations among biological relatives across the origin groups were highly significant. Spouse correlation, although significant was smaller, suggesting a stronger influence of genes than shared environment in the determination of the trait. Father-child correlation was significantly higher (r = 0.25) than mother-child value (r = 0.19), suggesting a possible paternal influence on BMI. There was also asymmetry in parent-offspring correlations by the sex of the offspring. Sibling correlation was higher (r = 0.33) than parent-offspring correlation (r = 0.22), suggesting that shared environment within generations tended to have some importance.