Department of Growth and Reproduction, University of Copenhagen, Copenhagen, Denmark.
PLoS One. 2009 Dec 24;4(12):e8450. doi: 10.1371/journal.pone.0008450.
Recent studies have shown that puberty starts at younger ages than previously. It has been hypothesized that the increasing prevalence of childhood obesity is contributing to this trend. The purpose of this study was to analyze the association between prepubertal body mass index (BMI) and pubertal timing, as assessed by age at onset of pubertal growth spurt (OGS) and at peak height velocity (PHV), and the secular trend of pubertal timing given the prepubertal BMI.
METHODOLOGY/PRINCIPAL FINDINGS: Annual measurements of height and weight were available in all children born from 1930 to 1969 who attended primary school in the Copenhagen municipality; 156,835 children fulfilled the criteria for determining age at OGS and PHV. The effect of prepubertal BMI at age seven on these markers of pubertal development within and between birth cohorts was analyzed. BMI at seven years was significantly inversely associated with age at OGS and PHV. Dividing the children into five levels of prepubertal BMI, we found a similar secular trend toward earlier maturation in all BMI groups.
CONCLUSION/SIGNIFICANCE: The heavier both boys and girls were at age seven, the earlier they entered puberty. Irrespective of level of BMI at age seven, there was a downward trend in the age at attaining puberty in both boys and girls, which suggests that the obesity epidemic is not solely responsible for the trend.
最近的研究表明，青春期开始的年龄比以前更早。有人假设，儿童肥胖症的患病率不断上升是导致这种趋势的原因。本研究的目的是分析青春期前体重指数（BMI）与青春期开始时间之间的关系，通过青春期生长突增（OGS）和身高增长峰值（PHV）的起始年龄来评估，以及考虑到青春期前 BMI 时青春期开始时间的长期趋势。
方法/主要发现：在哥本哈根市上小学的所有 1930 年至 1969 年出生的儿童中，都有每年身高和体重的测量数据；156835 名儿童符合确定 OGS 和 PHV 年龄的标准。分析了 7 岁时青春期前 BMI 对这些青春期发育标志物的影响，在出生队列内和之间。7 岁时的 BMI 与 OGS 和 PHV 的年龄呈显著负相关。将儿童分为五个青春期前 BMI 水平组，我们发现所有 BMI 组的成熟时间都呈现出相似的长期趋势。
结论/意义：男孩和女孩在 7 岁时越重，他们进入青春期的时间就越早。无论 7 岁时的 BMI 水平如何，男孩和女孩的青春期开始年龄都呈下降趋势，这表明肥胖症的流行并不是导致这一趋势的唯一原因。
