Population Research Unit, Department of Social Research, University of Helsinki, P.O. Box 18, 00014 University of Helsinki, Helsinki, Finland.
Paediatr Perinat Epidemiol. 2012 Nov;26(6):553-60. doi: 10.1111/ppe.12003.
Chest circumference (CC) is suggested to be a good indicator of early life nutrition, but little is known on the heritability of CC. Thus we analysed the effects of genetic and environmental factors on the development of CC in Japanese infants.
CC was measured longitudinally from birth until 1 year of age in a cohort of 211 monozygotic and 160 dizygotic complete Japanese twin pairs born in 1989-2002. The data were analysed using applications of structural linear equation modelling for twin data.
No sex-specific differences in the variance components were found. Environmental factors unique to each twin explained the major part of the variation of CC at birth whereas environmental factors shared by co-twins were more important at 1-3 months of age. From 3 months of age, the effect of genetic factors become steadily stronger and they explained the majority of the variation at 1 year of age. Strong genetic continuity in the development of CC was found, but also new sets of genes were activated during the first year of life. The origin of the environmental part of the variation could be tracked before 3 months of age. A substantial part of common and specific environmental factors affecting CC affected also birthweight.
CC is sensitive to intrauterine environmental factors, but these effects diminish during the first year of life, at least if postnatal environment is good. CC can be a useful indicator when identifying newborns who have suffered suboptimal pre-natal conditions.
胸围（CC）被认为是反映生命早期营养状况的良好指标，但有关 CC 遗传性的信息知之甚少。因此，我们分析了遗传和环境因素对日本婴儿 CC 发育的影响。
对 1989 年至 2002 年间出生的 211 对同卵双胞胎和 160 对异卵双胞胎进行了队列研究，从出生到 1 岁时对 CC 进行了纵向测量。使用结构线性方程模型分析双胞胎数据的应用程序对数据进行了分析。
未发现性别特异性方差分量差异。每个双胞胎特有的环境因素解释了 CC 在出生时的大部分变异，而双胞胎共同特有的环境因素在 1-3 个月时更为重要。从 3 个月开始，遗传因素的影响逐渐增强，并在 1 岁时解释了大部分变异。CC 发育过程中存在强烈的遗传连续性，但在生命的第一年也有新的基因组合被激活。在 3 个月之前可以追踪到环境变异部分的来源。影响 CC 的共同和特定环境因素的大部分对出生体重也有影响。
CC 对宫内环境因素敏感，但这些影响在生命的第一年逐渐减弱，前提是产后环境良好。CC 可以作为识别新生儿在产前条件不佳的有用指标。
