Increasing obesity is a world-wide health concern. Its most commonly used indicator, body mass index (BMI), consistently shows considerable genetic and shared environmental variance throughout life, the latter particularly in youth. Several adult studies have observed less total and genetically influenced variance with higher attained SES. These studies offer clues about sources of the 'obesity epidemic' but analogous youth studies of SES-of-origin are needed. Genetic and environmental influences and moderating effects of SES may vary in countries with different health policies, lifestyles, and degrees/sources of social inequality, offering further clues to the sources of the obesity epidemic. We examined SES-of-origin moderation of BMI variance in the German TwinLife study's cohorts assessed around ages 5, 11, 17, and 23-24, and in the Minnesota Twin Family Study's (MTFS) 11- and 17-year-old birth cohorts assessed longitudinally around ages 11, 17, and 23-24, comparing male and female twins and their parents. Age for age, both sexes' means and variances were greater in MTFS than in TwinLife. We observed that SES generally moderated genetic influences, more strongly in females, similar to most adult studies of attained-SES moderation of BMI. We interpreted differences in our SES-of-origin observations in light of inevitably-missing covariance between SES-of-origin and BMI in the models, mother-father and parent-offspring BMI correlations, and parental attained-SES-BMI correlations. We suggest that one source of the present obesity epidemic is social change that amplifies expression of genes both constraining SES attainment and facilitating weight gain.

中文翻译：

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青年社会经济地位 (SES-of-Origin) 和体重指数 (BMI)：比较德国和明尼苏达州。


日益严重的肥胖是一个世界性的健康问题。它最常用的指标是体重指数（BMI），在整个生命过程中始终显示出相当大的遗传和共同环境差异，后者尤其是在青年时期。一些成人研究发现，社会经济地位越高，总的和遗传影响的差异就越小。这些研究提供了有关“肥胖流行病”来源的线索，但需要对社会经济地位的起源进行类似的青年研究。在卫生政策、生活方式和社会不平等程度/来源不同的国家中，社会经济地位的遗传和环境影响以及调节作用可能会有所不同，这为肥胖流行的根源提供了进一步的线索。我们在德国 TwinLife 研究的 5、11、17 和 23-24 岁左右的队列中以及明尼苏达双胞胎家庭研究 (MTFS) 的 11 岁和 17 岁出生的队列中检查了 BMI 方差的 SES 调节。对 11 岁、17 岁和 23-24 岁的队列进行纵向评估，比较男性和女性双胞胎及其父母。 MTFS 中的年龄、性别均值和方差均大于 TwinLife。我们观察到，SES 通常会调节遗传影响，尤其是女性，这与大多数成人研究中获得的 SES 对 BMI 的调节相似。我们根据模型中不可避免地缺失的 SES 来源与 BMI 之间的协方差、母亲-父亲和父母-后代 BMI 相关性以及父母获得的 SES-BMI 相关性，解释了 SES 来源观察结果的差异。我们认为，当前肥胖流行的根源之一是社会变革，它放大了既限制社会经济地位获得又促进体重增加的基因表达。