OBJECTIVES: Abdominal visceral fat (AVF) is considered a risk factor for diabetes, atherogenic lipid profiles and hypertension. However, little is known about the genetic contribution to AVF as compared to total body fat. DESIGN: AVF was assessed by computerized tomography, and total body fat (fat mass) was assessed by underwater weighing in 86 families participating in the Heritage Family Study. All family members were sedentary at baseline examination. The familial factors underlying the variability in age-adjusted AVF, age-fat mass-adjusted AVF and age-adjusted fat mass, were assessed using a familial correlation model. RESULTS: The maximal heritability (including genetic and familial environmental effects) for AVF was comparable before (47%) and after (48%) adjusting for fat mass, and was 55% for fat mass itself in these sedentary 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), suggesting 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 and AVF, there appears to be a predominantly genetic etiology for the visceral component which is independent of total body fat. These findings imply that some individuals are more at risk than others because of an inherited tendency to store abdominal fat viscerally rather than subcutaneously.
Bibliographical noteFunding Information:
The HERITAGE study is supported by the NHLBI through the following grants: HL45670 (C Bouchard, PI), HL47323 (AS Leon, PI), HL47317 (DC Rao, PI), HL47327 (JS Skinner, PI), and HL47321 (JH Wil-more, PI). Thanks are expressed to all the co-principal investigators, investigators, co-investigators, local project coordinators, research assistants, laboratory technicians, and secretaries who are contributing to the study. Finally, the entire HERITAGE consortium is very thankful to those hard-working participating families whose involvement alone demonstrates the feasibility of this study.
- Total fat mass