Wells Jonathan C K
Pediatric Nutrition Childhood Nutrition Research Centre, Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK.
Best Pract Res Clin Endocrinol Metab. 2007 Sep;21(3):415-30. doi: 10.1016/j.beem.2007.04.007.
Sexual dimorphism in human body composition is evident from fetal life, but emerges primarily during puberty. At birth, males have a similar fat mass to females but are longer and have greater lean mass. Such differences remain detectable during childhood; however, females enter puberty earlier and undergo a more rapid pubertal transition, whereas boys have a substantially longer growth period. After adjusting for dimorphism in size (height), adult males have greater total lean mass and mineral mass, and a lower fat mass than females. These whole-body differences are complemented by major differences in tissue distribution. Adult males have greater arm muscle mass, larger and stronger bones, and reduced limb fat, but a similar degree of central abdominal fat. Females have a more peripheral distribution of fat in early adulthood; however, greater parity and the menopause both induce a more android fat distribution with increasing age. Sex differences in body composition are primarily attributable to the action of sex steroid hormones, which drive the dimorphisms during pubertal development. Oestrogen is important not only in body fat distribution but also in the female pattern of bone development that predisposes to a greater female risk of osteoporosis in old age. Disorders of sex development are associated with significant abnormalities of body composition, attributable largely to their impact on mechanisms of hormonal regulation.
人体成分的性别差异在胎儿期就很明显，但主要在青春期出现。出生时，男性的脂肪量与女性相似，但身高更长，瘦体重更大。这种差异在儿童期仍可检测到；然而，女性青春期开始较早，青春期过渡更快，而男孩的生长期则长得多。在调整了体型（身高）的差异后，成年男性的总瘦体重和矿物质含量比女性高，脂肪量比女性低。这些全身差异伴随着组织分布的主要差异。成年男性的手臂肌肉量更大，骨骼更大更强壮，肢体脂肪减少，但腹部中央脂肪量相似。女性在成年早期脂肪分布更外周；然而，随着年龄增长，更高的生育次数和绝经都会导致更像男性的脂肪分布。身体成分的性别差异主要归因于性类固醇激素的作用，这些激素在青春期发育过程中驱动了性别差异。雌激素不仅在身体脂肪分布中很重要，而且在女性骨骼发育模式中也很重要，这种模式使女性在老年时患骨质疏松症的风险更高。性发育障碍与身体成分的显著异常有关，这主要归因于它们对激素调节机制的影响。
