Family resemblance in body circumferences and their ratios: the Nancy family study.

The purpose of this study was to investigate the familial resemblance for individual body circumferences (suprailiac, waist, thigh and arm) and for the waist/suprailiac (as surrogate for the waist/hip) and the waist/thigh circumference ratios, in a sample of 216 unselected nuclear families with children aged 10-25 years. Familial correlations were jointly computed, using the maximum-likelihood method. The highest familial resemblance was observed for the waist circumference and for the waist/suprailiac and the waist/thigh circumference ratios. There was no significant difference between father-offspring and mother-offspring correlations when considering individual body circumferences. In contrast, when considering the two ratios there was a stronger mother-child than father-child similarity. Furthermore, there was a higher resemblance of the mother with her daughter than with her son, but no significant sib sex difference in the father-offspring relationship. There was also a heterogeneity of sibling correlations for the two ratios, the like-sex pairs exhibiting higher correlations than the unlike-sex pairs. Lastly, the similarity observed between spouses, of similar magnitude to the father-offspring correlation, suggests the contribution of environmental rather than genetic factors for explaining the familial resemblance of the two ratios. In conclusion, the great family resemblance for the waist/suprailiac and the waist/thigh circumference ratios (correlations ranging from 0.23 to 0.68) appears remarkable, and should be taken in consideration, given the predictive value of these indices for disease in adulthood.