Stunkard A J, Harris J R, Pedersen N L, McClearn G E
Department of Psychiatry, University of Pennsylvania, Philadelphia.
N Engl J Med. 1990 May 24;322(21):1483-7. doi: 10.1056/NEJM199005243222102.
To assess the relative importance of genetic and environmental effects on the body-mass index (weight in kilograms divided by the square of the height in meters), we studied samples of identical and fraternal twins, reared apart or reared together. The samples consisted of 93 pairs of identical twins reared apart, 154 pairs of identical twins reared together, 218 pairs of fraternal twins reared apart, and 208 pairs of fraternal twins reared together. The intrapair correlation coefficients of the values for body-mass index of identical twins reared apart were 0.70 for men and 0.66 for women. These are the most direct estimates of the relative importance of genetic influences (heritability) on the body-mass index, and they were only slightly lower than those for twins reared together in this and earlier studies. Similar estimates were derived from maximum-likelihood model-fitting analyses--0.74 for men and 0.69 for women. Nonadditive genetic variance made a significant contribution to the estimates of heritability, particularly among men. Of the potential environmental influences, only those unique to the individual and not those shared by family members were important, contributing about 30 percent of the variance. Sharing the same childhood environment did not contribute to the similarity of the body-mass index of twins later in life. We conclude that genetic influences on body-mass index are substantial, whereas the childhood environment has little or no influence. These findings corroborate and extend the results of earlier studies of twins and adoptees.
为了评估基因和环境因素对体重指数（体重千克数除以身高米数的平方）的相对重要性，我们研究了分开抚养或共同抚养的同卵双胞胎和异卵双胞胎样本。这些样本包括93对分开抚养的同卵双胞胎、154对共同抚养的同卵双胞胎、218对分开抚养的异卵双胞胎以及208对共同抚养的异卵双胞胎。分开抚养的同卵双胞胎体重指数值的组内相关系数，男性为0.70，女性为0.66。这些是对基因影响（遗传率）对体重指数相对重要性的最直接估计，并且在本研究及早期研究中，它们仅略低于共同抚养的双胞胎的相关系数。通过最大似然模型拟合分析也得出了类似的估计值——男性为0.74，女性为0.69。非加性基因方差对遗传率估计有显著贡献，尤其是在男性中。在潜在的环境影响因素中，只有个体特有的因素而非家庭成员共有的因素是重要的，其贡献了约30%的方差。共享相同的童年环境对双胞胎成年后的体重指数相似性没有影响。我们得出结论，基因对体重指数的影响很大，而童年环境影响很小或没有影响。这些发现证实并扩展了早期对双胞胎和领养者研究的结果。
