Davis Shanlee M, Kaar Jill L, Ringham Brandy M, Hockett Christine W, Glueck Deborah H, Dabelea Dana
University of Colorado, Department of Pediatrics, Denver, USA.
Children's Hospital Colorado, Aurora, USA.
J Pediatr Endocrinol Metab. 2019 Nov 26;32(11):1235-1239. doi: 10.1515/jpem-2019-0243.
Background Sex differences in body composition are appreciated throughout the lifespan with probable contributions from sex steroids: testosterone and estrogen. The purpose of this longitudinal observational study was to determine if sex differences in body composition emerge during the first months of life in healthy infants, corresponding to the age at which male infants produce endogenous testosterone. Methods Linear growth and body composition parameters using air displacement plethysmography were obtained from 602 healthy infants after birth and again at 5 months of age. Rate of change in body composition parameters were compared between sexes. Results Sex differences in length, total mass, fat free mass (FFM), and percent fat mass (%FM) were present both at birth and at 5 months (p < 0.001 for all), with males having greater total mass and FFM but lower %FM. Gain in %FM over the first 5 months was significantly lower in males (p = 0.0004). This difference was secondary to a gain of 17 g/week more in FFM in males compared to females. Conclusions Sex differences in body composition emerge in the first months of life, with lower adiposity accumulation in males. Endogenous testosterone production in males ~1-4 months of age may account for findings and may have lifelong implications for sex differences in body composition.
在整个生命周期中，身体成分存在性别差异，这可能与性类固醇（睾酮和雌激素）有关。这项纵向观察性研究的目的是确定在健康婴儿出生后的头几个月，即男婴产生内源性睾酮的年龄，身体成分的性别差异是否会出现。方法：使用空气置换体积描记法获得602名健康婴儿出生后及5个月大时的线性生长和身体成分参数。比较两性身体成分参数的变化率。结果：出生时和5个月大时，男女在身长、总体质量、去脂体重（FFM）和体脂百分比（%FM）方面均存在性别差异（所有p值均<0.001），男性总体质量和FFM较高，但%FM较低。男性在出生后头5个月%FM的增加明显低于女性（p = 0.0004）。这种差异是由于男性FFM每周比女性多增加17克。结论：身体成分的性别差异在生命的头几个月就已出现，男性的体脂积累较少。男性1至4个月大时内源性睾酮的产生可能是导致这些结果的原因，并且可能对身体成分的性别差异产生终身影响。
