Pierce Mary B, Leon David A
London School of Hygiene and Tropical Medicine, London, United Kingdom.
Am J Clin Nutr. 2005 Oct;82(4):733-9. doi: 10.1093/ajcn/82.4.733.
Few studies have examined whether the inverse association of age at menarche with adult body mass index (BMI) is due to the tendency of BMI to track between childhood and adult life, with childhood BMI playing a causal role in determining age at menarche.
The objective was to investigate whether the association of younger age at menarche with a high BMI and increased likelihood of obesity in middle age is due to confounding with early childhood BMI.
In a historical cohort of 3743 Scottish females born between 1950 and 1955, height and weight were measured in early childhood, and age at menarche and height and weight in middle age were obtained by questionnaire.
The age-adjusted change in mean adult BMI per additional year of age at menarche was -0.64 (95% CI: -0.78, -0.50). Adjustment for childhood BMI measured between 4 and 6 y reduced this value to -0.57 (-0.71, -0.43). Adjustment for childhood and adult social class, parity, smoking, and alcohol intake had little effect. The odds ratio for being obese compared with not being obese in adulthood was 0.82 (0.76, 0.86) per 1-y increase in age at menarche and was unchanged by adjustment for childhood BMI and other covariates.
The inverse association of age at menarche with BMI and obesity in middle age is not explained by confounding by early childhood BMI. Instead, age at menarche may simply be a proxy marker for the pace of sexual maturation, which itself leads to differences in adiposity (and BMI) in the peripubertal period that track into adult life.
很少有研究探讨初潮年龄与成人身体质量指数（BMI）之间的负相关关系是否归因于BMI在儿童期和成年期之间的追踪趋势，即儿童期BMI在决定初潮年龄方面起因果作用。
研究初潮年龄较小与中年时高BMI及肥胖可能性增加之间的关联是否因儿童早期BMI的混杂作用所致。
在一个历史队列中，对1950年至1955年出生的3743名苏格兰女性进行研究，在儿童早期测量身高和体重，并通过问卷调查获取初潮年龄以及中年时的身高和体重。
初潮年龄每增加一岁，经年龄调整后的成人平均BMI变化为-0.64（95%可信区间：-0.78，-0.50）。对4至6岁时测量的儿童期BMI进行调整后，该值降至-0.57（-0.71，-0.43）。对儿童期和成年期社会阶层、产次、吸烟和饮酒量进行调整影响不大。初潮年龄每增加1岁，成年期肥胖与非肥胖的比值比为0.82（0.76，0.86），对儿童期BMI和其他协变量进行调整后该比值比无变化。
初潮年龄与中年时BMI和肥胖之间的负相关关系不能用儿童早期BMI的混杂作用来解释。相反，初潮年龄可能仅仅是性成熟速度的一个替代指标，性成熟速度本身会导致青春期前后肥胖（及BMI）的差异，并持续到成年期。
