FAMILIAL RESEMBLANCE FOR ABDOMINAL VISCERAL FAT - THE HERITAGE FAMILYSTUDY

OBJECTIVES: Abdominal visceral fat (AVF) is considered a risk factor f or diabetes, atherogenic lipid profiles and hypertension. However, lit tle is known about the genetic contribution to AVF as compared to tota l body fat. DESIGN: AVF was assessed by computerized tomography, and t otal body fat (fat mass) was assessed by underwater weighing in 86 fam ilies participating in the Heritage Family Study. All family members w ere sedentary at baseline examination, The familial factors underlying the variability in age-adjusted AVF, age-fat mass-adjusted AVF and ag e-adjusted fat mass, were assessed using a familial correlation model. RESULTS: The maximal heritability (including genetic and familial env ironmental effects) for AVF was comparable before (47%) and after (48% ) adjusting for fat mass, and was 55% for fat mass itself in these sed entary families. Spouse correlations were significant for fat mass and for AVF prior to, but not after, adjustment for fat mass. CONCLUSIONS : These results confirm the only previous study which investigated the familial aggregation of AVF (both in pattern and magnitude), suggesti ng that the factors underlying AVF in these sedentary families may be similar to those in the population at large. Although both genetic and familial environmental factors probably influence each of fat mass an d AVF, there appears to be a predominantly genetic etiology for the vi sceral component which is independent of total body fat, these finding s imply that some individuals are more at risk than others because of an inherited tendency to store abdominal fat viscerally rather than su bcutaneously.