Prenatal factors, childhood growth trajectories and age at menarche
Prenatal factors, childhood growth trajectories and age at menarche
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DOI：
10.1093/ije/31.2.405
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发表时间：
2002-04-01
影响因子：
7.7
通讯作者：
Wadsworth, MEJ
中科院分区：
文献类型：
--
作者：
Silva, ID;De Stavola, BL;Wadsworth, MEJ
在最近的研究中，较大的出生尺寸已被证明可以推迟月经初潮的时间。然而，这种关联背后的机制尚不清楚，因为出生体重是儿童时期体型的一个预测指标，而体型大则与月经初潮早有关。方法采用2547名1946年出生的英国女孩的代表性队列数据，对这些女孩进行了整个童年期的前瞻性随访。可以获得关于产前特征、出生体重、身高、体重和儿童时期的社会环境以及初潮年龄的信息。使用随机系数模型估计个体身高和体重指数（BMI）至7岁的轨迹。这些模型确定的参数随后被纳入Weibull生存模型，包括初潮时间和出生体重。结果出生体重对2岁时身高和BMI值有正向影响，但对2 - 7岁时身高和BMI值的变化率没有影响。最初的分析表明，低出生体重与初潮的早发有关，但在控制了婴儿时期的生长后，这种影响被逆转了，出生时体重较重的女孩比其他婴儿生长相似的女孩更早到达初潮。婴儿时期的快速生长也与青春期早熟有关。然而，当进一步控制2岁至7岁的生长时，出生体重和婴儿生长的影响消失了。结论出生体重和婴儿生长对月经初潮时间的影响似乎是通过儿童早期生长介导的。这些发现与月经初潮的时间可能在子宫内或生命早期确定的可能性是一致的，尽管它可能因儿童时期身体大小和成分的变化而改变。
Background In recent studies a larger birth size has been shown to delay the timing of menarche. The mechanisms underlying this association are not clear, however, as birthweight is a predictor of body size in childhood, and a large body size is known to be associated with an early onset of menarche.Methods Data from a representative British cohort of 2547 girls born in 1946 who were followed prospectively throughout childhood were used. Information was available on prenatal characteristics, birthweight, height, weight and social circumstances during childhood, and on age at menarche. Random coefficients models were used to estimate the individual trajectories in height and body mass index (BMI) up to age 7 years. The parameters identified by these models were then included in Weibull survival models for the timing of menarche together with birthweight.Results Birthweight was found to positively influence height and BMI values at age 2 years, but not to affect their rates of change from age 2 to 7 years. Initial analyses showed low birthweight to be associated with an early onset of menarche, but after controlling for growth in infancy this effect was reversed, with girls who were heavy at birth reaching menarche earlier than others with similar infant growth. Rapid growth in infancy was also related to early pubertal maturation. The effects of birthweight and infant growth disappeared, however, when further controlled for growth from age 2 to 7 years.Conclusions The effects of birthweight and growth in infancy on the timing of menarche seem to be mediated through growth in early childhood. These findings are consistent with the possibility that timing of menarche may be set in utero or early in life, although it may be modified by changes in body size and composition in childhood.