Lee Joyce M, Kaciroti Niko, Appugliese Danielle, Corwyn Robert F, Bradley Robert H, Lumeng Julie C
Division of Pediatric Endocrinology, Child Health Evaluation and Research Unit, University of Michigan, 300 NIB, Room 6E08, Campus Box 5456, Ann Arbor, MI 48109-5456, USA.
Arch Pediatr Adolesc Med. 2010 Feb;164(2):139-44. doi: 10.1001/archpediatrics.2009.258.
To examine the association between body mass index (BMI [calculated as weight in kilograms divided by height in meters squared]) and timing of pubertal onset in a population-based sample of US boys.
Longitudinal prospective study.
Ten US sites that participated in the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development.
Of 705 boys initially enrolled in the study, information about height and weight measures and pubertal stage by age 11.5 years was available for 401 boys.
The BMI trajectory created from measured heights and weights at ages 2, 3, 4.5, 7, 9, 9.5, 10.5, and 11.5 years.
Onset of puberty at age 11.5 years as measured by Tanner genitalia staging.
Boys in the highest BMI trajectory (mean BMI z score at age 11.5 years, 1.84) had a greater relative risk of being prepubertal compared with boys in the lowest BMI trajectory (mean BMI z score at age 11.5 years, -0.76) (adjusted relative risk = 2.63; 95% confidence interval, 1.05-6.61; P = .04).
The relationship between body fat and timing of pubertal onset is not the same in boys as it is in girls. Further studies are needed to better understand the physiological link between body fat and timing of pubertal onset in both sexes.
在美国男孩的一个基于人群的样本中，研究体重指数（BMI[计算方法为体重（千克）除以身高（米）的平方]）与青春期开始时间之间的关联。
纵向前瞻性研究。
参与美国国立儿童健康与人类发展研究所早期儿童保育与青少年发展研究的10个美国地点。
最初纳入该研究的705名男孩中，401名男孩有11.5岁时的身高、体重测量信息以及青春期阶段信息。
根据2岁、3岁、4.5岁、7岁、9岁、9.5岁、10.5岁和11.5岁时测量的身高和体重得出的BMI轨迹。
用坦纳生殖器分期法测量的11.5岁时青春期开始情况。
BMI轨迹最高的男孩（11.5岁时平均BMI z评分，1.84）与BMI轨迹最低的男孩（11.5岁时平均BMI z评分，-0.76）相比，青春期前的相对风险更高（调整后相对风险=2.63；95%置信区间，1.05 - 6.61；P = 0.04）。
男孩体内脂肪与青春期开始时间之间的关系与女孩不同。需要进一步研究以更好地理解两性体内脂肪与青春期开始时间之间的生理联系。
