Familial aggregation of body mass index: a population-based family study in eastern Finland

In this study, we investigated the familial aggregation of body mass index (BMI) in a sample of families with young offspring from eastern Finland. 15-year-olds were examined from 1996 to 1997, and their biological parents were examined from 1993 to 1994. 224 children were invited; 184 families participated, and 144 were included in the analysis with complete data. Significant positive correlations were found for mother-offspring pairs (correlation [r] = 0.31, p < 0.001, n = 140), father-offspring (r = 0.23, p = 0.017, n = 107), mother-daughter (r = 0.26, p = 0.044, n = 63) and mother-son (r = 0.36, p = 0.001, n = 77). Adjustment for confounding variables did not alter these results. There was a higher proportion of children in the highest quartile of BMI when the mother was obese (odds ratio [OR] = 3.0, 95 % CI = 1.4 - 6.7, n = 140) and when one or both parents were obese (OR = 2.8, 95 % CI = 1.0 - 8.0 when one parent was obese; OR = 4.6, 95 % CI = 1.1 - 20.0 when both parents were obese; n = 103). The study confirmed familial BMI aggregation. The consistent obesity relationship between mother and offspring may indicate the key role of the mother in primary obesity prevention.