Effect of Body Composition Methodology on Heritability Estimation of Body Fatness.
Effect of Body Composition Methodology on Heritability Estimation of Body Fatness.
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DOI：
10.2174/1874288201206010048
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发表时间：
2012-04-05
期刊：
影响因子：
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通讯作者：
Neale MC
中科院分区：
文献类型：
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作者：
Elder SJ;Roberts SB;McCrory MA;Das SK;Fuss PJ;Pittas AG;Greenberg AS;Heymsfield SB;Dawson-Hughes B;Bouchard TJ Jr;Saltzman E;Neale MC
人体肥胖的遗传力估计差异很大，身体成分方法对这种变异性的贡献是未知的。在78个成年男性和女性的单卵双生子对分开或一起饲养的身体组成的方法估计的遗传和环境的贡献，体脂变化的影响进行了研究。身体成分通过六种方法评估-身体质量指数（BMI），双能X线吸收法（DXA），水下称重（UWW），全身水分（TBW），生物电阻抗（BIA）和皮褶厚度。体脂率表示为体脂百分比、脂肪量和脂肪量/身高2，以评估体脂率表达对遗传率估计值的影响。模型拟合多变量分析用于评估方差的遗传和环境成分。平均BMI为24.5 kg/m2（范围为17.8-43.4 kg/m2）。身体组成方法对遗传力估计有显著影响（p<0.001），UWW对脂肪量/身高的估计最高（69%），BIA对脂肪量/身高的估计最低（47%）2。与脂肪质量/身高2（p=0.015）相比，将体脂表达为体脂百分比导致遗传力估计值显著更高（平均高出10.3%）。DXA和TBW方法表示身体脂肪的脂肪量/高度2给出了最小的偏差遗传力评估，基于特定遗传因素对其遗传方差的小贡献。DXA和TBW方法相结合的模型导致相对较低的FM/ht 2遗传力估计为60%，共同和独特的环境因素（分别为22%和18%）的显着贡献。体脂遗传力估计为60%，表明遗传方差对总方差的贡献比许多以前使用不太强大的研究设计的研究所表明的要小。研究结果还强调了环境因素的重要性，可能是基因型与环境的相互作用在体重增加和肥胖流行的病因学中的作用。
Heritability estimates of human body fatness vary widely and the contribution of body composition methodology to this variability is unknown. The effect of body composition methodology on estimations of genetic and environmental contributions to body fatness variation was examined in 78 adult male and female monozygotic twin pairs reared apart or together. Body composition was assessed by six methods – body mass index (BMI), dual energy x-ray absorptiometry (DXA), underwater weighing (UWW), total body water (TBW), bioelectric impedance (BIA), and skinfold thickness. Body fatness was expressed as percent body fat, fat mass, and fat mass/height2 to assess the effect of body fatness expression on heritability estimates. Model-fitting multivariate analyses were used to assess the genetic and environmental components of variance. Mean BMI was 24.5 kg/m2 (range of 17.8–43.4 kg/m2). There was a significant effect of body composition methodology (p<0.001) on heritability estimates, with UWW giving the highest estimate (69%) and BIA giving the lowest estimate (47%) for fat mass/height2. Expression of body fatness as percent body fat resulted in significantly higher heritability estimates (on average 10.3% higher) compared to expression as fat mass/height2 (p=0.015). DXA and TBW methods expressing body fatness as fat mass/height2 gave the least biased heritability assessments, based on the small contribution of specific genetic factors to their genetic variance. A model combining DXA and TBW methods resulted in a relatively low FM/ht2 heritability estimate of 60%, and significant contributions of common and unique environmental factors (22% and 18%, respectively). The body fatness heritability estimate of 60% indicates a smaller contribution of genetic variance to total variance than many previous studies using less powerful research designs have indicated. The results also highlight the importance of environmental factors and possibly genotype by environmental interactions in the etiology of weight gain and the obesity epidemic.