Miljkovic-Gacic Iva, Wang Xiaojing, Kammerer Candace M, Bunker Clareann H, Patrick Alan L, Wheeler Victor W, Kuller Lewis H, Evans Rhobert W, Zmuda Joseph M
Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA 15261, USA.
Metabolism. 2008 Jun;57(6):819-23. doi: 10.1016/j.metabol.2008.01.022.
Very few studies have comprehensively defined the genetic and environmental influences on body fat storage in the arms and legs and their association with diabetes, especially in families of African heritage. We analyzed body fat distribution by dual-energy x-ray absorptiometry (percentage total fat, percentage trunk fat, percentage arm fat, and percentage leg fat) and fasting serum glucose in 471 individuals (mean age, 43 years) from 8 multigenerational Afro-Caribbean families (mean family size = 51; 3535 relative pairs). Diabetes was inversely associated with percentage leg fat (P = .009) and, to some extent, positively associated with percentage arm fat independent of age, sex, and body size (P = .08), but not with anthropometric or dual-energy x-ray absorptiometric measures of total and central adiposity. Furthermore, percentage leg fat was inversely, whereas percentage arm fat was positively, associated with body mass index, waist circumference, and serum glucose (P < .01). Residual heritability (h2r) for arm and leg fat was significant (P < .01) and high: 62% (for percentage arm fat) and 40% (for percentage leg fat). Moreover, sex-specific h2r for leg fat was considerably higher (P = .02) in women than in men (h2r values, 58% vs 17%, respectively). Genetic correlation (rho(G)) between arm and leg fat was -0.61 (P < .01), suggesting that only 37% of the covariation between these 2 adipose tissue depots may be due to shared genetic influences. This study provides new evidence for a strong genetic and sex contribution to upper and lower body fat, with relatively little covariation between these traits due to shared genes. Our findings also suggest that, in this population, leg fat is associated with diabetes independent of overall adiposity.
极少有研究全面界定基因和环境因素对上肢和下肢体脂储存的影响及其与糖尿病的关联，尤其是在非洲裔家庭中。我们采用双能X线吸收法分析了来自8个多代加勒比裔非洲家庭（平均家庭规模=51人；3535个亲属对）的471名个体（平均年龄43岁）的体脂分布（总脂肪百分比、躯干脂肪百分比、上肢脂肪百分比和下肢脂肪百分比）以及空腹血清葡萄糖水平。糖尿病与下肢脂肪百分比呈负相关（P = 0.009），在一定程度上与上肢脂肪百分比呈正相关，且不受年龄、性别和体型影响（P = 0.08），但与总体及中心性肥胖的人体测量指标或双能X线吸收法测量结果无关。此外，下肢脂肪百分比与体重指数、腰围和血清葡萄糖呈负相关，而上肢脂肪百分比与之呈正相关（P < 0.01）。上肢和下肢脂肪的残差遗传度（h2r）显著（P < 0.01）且较高：上肢脂肪百分比为62%，下肢脂肪百分比为40%。此外，女性下肢脂肪的性别特异性h2r显著高于男性（P = 0.02）（h2r值分别为58%和17%）。上肢和下肢脂肪之间的遗传相关性（rho(G)）为-0.61（P < 0.01），表明这两个脂肪组织库之间仅有37%的协变量可能归因于共同的基因影响。本研究为基因和性别对上下肢体脂有强烈影响提供了新证据，由于共享基因，这些性状之间的协变量相对较少。我们的研究结果还表明，在该人群中，下肢脂肪与糖尿病相关，且独立于总体肥胖情况。
