FAMILIAL AGGREGATION AND HERITABILITY OF WAIST-TO-HIP RATIO IN ADULT WOMEN - THE IOWA WOMENS HEALTH STUDY

The aim of this study was to assess evidence that genetic factors infl uence body fat distribution. First-degree relatives of 324 cancer-free females in a population-based prospective study of 41,837 women (99% white) between the ages of 55 and 69 at baseline in 1986 were studied. A total of 396 living sisters (mean age 65.7 years) and 446 living da ughters (mean age 41.2 years) were identified through a mailed 'family tree' questionnaire sent to each participant. Family members were mai led a questionnaire to obtain self-reported measures of current height and weight. A paper tape measure and written instructions were enclos ed to obtain waist and hip circumferences. The age adjusted mother-dau ghters correlations for waist-to-hip ratio and body mass index (kg/m(2 )) were 0.19 and 0.23, respectively (P < 0.05 using Fisher's z-transfo rmation). The corresponding sister-sister correlations were 0.23 and 0 .19, respectively (P < 0.05). The sister-sister correlations were not significantly different from the mother-daughter correlations. After a djustment for body mass index the mother-daughter correlation for wais t-to-hip ratio increased to 0.20 and the sister-sister correlation inc reased to 0.26. These familial correlations suggest that genes and com mon environment may contribute 40 to 50% of the total variance of wais t-to-hip ratio in white women in the Midwest.