Longitudinal Associations between Obesity and Depression: A Community-Based Study

描述(申请人提供)：肥胖和严重抑郁障碍(MDD)越来越常见，并以医疗保健费用、生产力丧失和个人痛苦的形式给个人和社会带来巨大代价。这些疾病同时发生的几率大于偶然性，尽管具体是如何发生的，在哪些人中发生，以及为什么还不清楚。这个项目将以三种不同的方式处理这个问题。在目标1中，使用纵向前瞻性设计，将在从童年到成年早期期间检查早期MDD预测后期肥胖开始的程度和早期肥胖预测后期MDD开始的程度；这将使我们能够确定这种共病发展的特殊风险时期。在目标2中，将通过确定父母的MDD和肥胖症与青春期晚期子女患这些疾病的风险之间的关系来检查家庭内这些疾病之间的联系。在目标3中，将使用纵向同双胞胎对照和同双胞胎差异设计来研究MDD和肥胖症之间可能的因果关系。在同卵双胞胎对照设计中，双胞胎之一患有感兴趣的障碍(例如，MDD)，另一对没有随着时间的推移而被跟踪，以检查另一种障碍(例如，肥胖)的发展。如果有较早障碍的双胞胎与没有障碍的同卵双胞胎相比，患上较晚障碍的风险更高，这表明较早的障碍创造了一种经验背景，对后来的障碍的发展具有因果影响。如果没有初始障碍的双胞胎显示出后来出现障碍的风险，TAT与有初始障碍的同卵双胞胎的风险相当，这表明一个人可能不是另一个人发展的因果链的一部分。不和谐的同卵双胞胎特别有信息量，因为他们拥有相同的基因组成和养育环境。同卵双胞胎差异分析扩展了同卵双生对照设计，利用这些相同的原则，通过使用体重指数和MDD症状的整个样本和维度测量，最大限度地提高统计能力。为了解决这些目标，将使用明尼苏达州双胞胎家庭研究的档案数据。这是一个以社区为基础的双胞胎及其父母的样本，从11岁到29岁(最多6个时间点)，每3-4年对青少年进行一次MDD和肥胖症的临床评估，以及对他们父母的MDD和肥胖症进行临床评估。不同年龄的青少年样本大小从2510到3762不等，每次评估的随访率都在87%以上。此外，还有3622名家长的数据。为了最大限度地提高公众健康影响和统计能力，计划进行维度和分类分析。通过阐明MDD和肥胖症之间的纵向联系，这些家庭内部障碍之间的联系，以及这些障碍之间潜在的因果关系，这个项目很有可能对这些联系有更好的理解。

DESCRIPTION (provided by applicant): Obesity and major depressive disorder (MDD) are increasingly common and pose enormous costs to individuals and society in the forms of health-care expenses, lost productivity, and personal distress. These disorders co-occur at rates greater than chance, though the specifics of how, among whom, and why remain unclear. This project will approach this issue in three different ways. In Aim #1, using a longitudinal prospective design, the degree to which earlier MDD predicts the onset of later obesity and the degree to which earlier obesity predicts the onset of later MDD will be examined during the period from childhood through early adulthood; this will enable us to identify periods of particula risk for the development of this comorbidity. In Aim #2, associations between these disorders within families will be examined by determining how MDD and obesity in parents are associated with risk for these same disorders in late-adolescent offspring. In Aim #3, possible causal associations between MDD and obesity will be investigated using longitudinal co-twin control and co-twin difference designs. In the co-twin control designs, twin pairs in which one has the disorder of interest (e.g., MDD) and the other does not are followed over time to examine the development of another disorder (e.g., obesity). If the twin with the earlier disorder is at increased risk for the later disorder compared to the co-twin without the disorder, this points to the earlier disorder creating an experiential context with a causal influence on the development of the later disorder. If the twin without the initial disorder shows risk for the later disorder tat is equivalent to that of the co-twin with the initial disorder, this points to the likelihood that oneis not part of the causal chain for the development of the other. Discordant monozygotic twins are particularly informative because they share both the same genetic make-ups and rearing environments. Co-twin difference analyses extend the co-twin control design by utilizing these same principles to maximize statistical power by using the entire sample and dimensional measures of body mass index and MDD symptoms. To address these Aims, archival data from the Minnesota Twin Family Study will be used. This is a community-based sample of twins and their parents, with clinical assessments of MDD and obesity every 3-4 years from ages 11 to 29 (up to 6 time points) in the youth, as well as clinical assessments of MDD and obesity in their parents. The youth sample sizes at different ages range from 2,510 to 3,762, with follow-up rates above 87% at each assessment. In addition, data are available on 3,622 parents. To maximize both public health impact and statistical power, both dimensional and categorical analyses are planned. By elucidating longitudinal associations between MDD and obesity, the associations between these disorders within families, and the potential causal paths between these disorders, this project has a high likelihood of yielding an improved understanding of these associations.