Department of Sociology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599;
Lineberger Comprehensive Cancer Center, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599.
Proc Natl Acad Sci U S A. 2021 Apr 27;118(17). doi: 10.1073/pnas.2020167118.
No research exists on how body mass index (BMI) changes with age over the full life span and social disparities therein. This study aims to fill the gap using an innovative life-course research design and analytic methods to model BMI trajectories from early adolescence to old age across 20th-century birth cohorts and test sociodemographic variation in such trajectories. We conducted the pooled integrative data analysis (IDA) to combine data from four national population-based NIH longitudinal cohort studies that collectively cover multiple stages of the life course (Add Health, MIDUS, ACL, and HRS) and estimate mixed-effects models of age trajectories of BMI for men and women. We examined associations of BMI trajectories with birth cohort, race/ethnicity, parental education, and adult educational attainment. We found higher mean levels of and larger increases in BMI with age across more recent birth cohorts as compared with earlier-born cohorts. Black and Hispanic excesses in BMI compared with Whites were present early in life and persisted at all ages, and, in the case of Black-White disparities, were of larger magnitude for more recent cohorts. Higher parental and adulthood educational attainment were associated with lower levels of BMI at all ages. Women with college-educated parents also experienced less cohort increase in mean BMI. Both race and education disparities in BMI trajectories were larger for women compared with men.
目前尚无研究探讨人体质量指数（BMI）在整个生命周期中随年龄的变化情况，以及其中存在的社会差异。本研究旨在采用创新的生命历程研究设计和分析方法填补这一空白，以模型的方式来描绘 20 世纪出生队列中从青少年早期到老年期的 BMI 轨迹，并检验这些轨迹中的社会人口差异。我们开展了合并综合数据分析（IDA），对来自四项美国国立卫生研究院（NIH）纵向队列研究的数据进行了合并，这些研究共同涵盖了生命历程的多个阶段（“成长中的一代”研究、美国中年纵向研究、成人冠状动脉风险发展研究和健康与退休研究），并估计了 BMI 随年龄变化的混合效应模型，该模型适用于男性和女性。我们考察了 BMI 轨迹与出生队列、种族/民族、父母教育程度和成人教育程度之间的关联。结果发现，与较早出生的队列相比，最近出生的队列中 BMI 随年龄增长的平均值更高，增幅也更大。与白人相比，黑人及西班牙裔的 BMI 存在早期和终生的增长过剩现象，而且在黑人和白人之间的 BMI 差异中，最近出生的队列中差异的幅度更大。父母和成人的受教育程度越高，在各个年龄段的 BMI 水平就越低。父母受过大学教育的女性，其平均 BMI 随队列的增长幅度也较小。BMI 轨迹的种族和教育差异在女性中比男性更大。
