Dual-Cohort Prospective Study of Obesity

 描述(由申请者提供)：与在美国出生的移民相比，移民的肥胖率通常较低。然而，随着时间的推移，移民中的肥胖率会上升，并向美国出生的人趋同。移民人数的增加通常被归因于文化适应，指的是采用了“美国”的行为和规范。然而，全球化刺激了“美国”商品和做法在世界各地的营销和采用，肥胖率在全球范围内不断上升。这些观察提出了关于长期趋势的问题，并暗示了移民如果没有移民是否会增加体重的反事实。对移民的研究往往无法解决长期趋势和全球变化的问题，因为它们的设计初衷并不是这样做的。为了研究这些问题，我们提出了三个具体目标：(1)进行双队列前瞻性跨国研究；(2)比较两个队列中肥胖危险因素的变化；(3)检验两个队列中肥胖风险变化的中介和调节因素。这项研究建议前瞻性地跟踪两个成人队列，为期三年。第一批移民(n=800)将从菲律宾前往美国。第二批非移民(n=800)将在菲律宾境内跟进。使用双队列设计类似于以迁徙为“治疗”的自然实验。移民将从参加菲律宾海外华人委员会(CFO)举办的强制性研讨会的参与者中抽样。CFO是菲律宾政府机构，负责监管来自该国的所有合法永久移民。我们与CFO的独特关系使我们能够在移民到美国前1-2个月对移民进行评估。这提供了以前没有的关于移民的新信息。移民将从参加强制性CFO培训课程的移民名单中抽样。将对居住在菲律宾马尼拉和宿务地区的人进行分层抽样，对非移民进行抽样。非移民将每年接受评估，总共4波数据(基线、第一年、第二年、第三年)；移民将以同样的方式进行评估，外加进入美国2-3个月后的一次额外评估。我们将测量人体测量学、通过干血迹、饮食和体力活动的生物标记物，并进行调查。统计分析将包括评估时间轨迹的线性混合效应模型(目标1)、调解分析(目标2)和缓和测试(目标3)。我们将使用倾向分数匹配来减少由于混淆而产生的偏差。这项研究的结果将提供关于移民移民前经历的难得和独特的信息，提供关于世俗趋势与文化适应的严格检验，评估一个新的概念框架，并提供有价值的信息，以根据这些信息制定预防工作，以减少重要移民人口的肥胖负担和相关状况。

 DESCRIPTION (provided by applicant): Immigrants often have lower rates of obesity compared to their U.S. born counterparts. However, over time, rates of obesity rise among immigrants and converge to the U.S. born. This rise among immigrants is often attributed to acculturation, referring to the adoption of "American" behaviors and norms. Yet, globalization has spurred the marketing and adoption of "American" goods and practices across the world, and rates of obesity are rising worldwide. These observations raise questions about secular trends and imply the counterfactual of whether immigrants would have gained weight without migration. Studies of immigrants often fail to address the issues of secular trends and global changes because they are not designed to do so. To study these issues, we propose three specific aims: (1) to conduct a dual- cohort prospective, transnational study; (2) compare changes in obesity risk factors between two cohorts; (3) examine the mediators and moderators of change in obesity risk for both cohorts. This study proposes to prospectively follow two cohorts of adults for three years. The first cohort of migrants (n=800) will be followed from the Philippines to the United States. The second cohort of non-migrants (n=800) will be followed within the Philippines. The use of a dual cohort design is analogous to a natural experiment with migration as the "treatment." Migrants will be sampled from participants attending a mandatory seminar offered by the Commission for Filipinos Overseas (CFO), the Philippines governmental agency that regulates all legal permanent migration from the country. Our unique relationship with the CFO allows us the ability to assess migrants 1-2 months prior to emigration to the U.S. This provides novel information about migrants that have not been previously available. Migrants will be sampled from a list of migrants attending mandatory CFO training sessions. Non- migrants will be sampled using stratified sampling of persons living in the areas of Metropolitan Manila and Cebu, Philippines. Non-migrants will be assessed annually, for a total of 4 waves of data (baseline, year 1, year 2, year 3); migrants will be assessed in the same way, plus one additional assessment 2-3 months after entry into the U.S. We will measure anthropometrics, biomarkers through dried blood spots, dietary and physical activity, and administer a survey. Statistical analyses will include linear mixed effects models to assess the trajectories over time (Aim 1), mediation analyses (Aim 2), and tests of moderation (Aim 3). We will use propensity score matching to reduce bias due to confounding. The results of this study will provide rare and unique information about the pre-migration experiences of emigrants, provide rigorous a test of secular trends versus acculturation, evaluate a novel conceptual framework, and provide valuable information from which to develop prevention efforts to reduce the burden of obesity and related conditions among an important immigrant population.