The Association between obesity, central adiposity and endocrine disruptors

描述（由申请人提供）：在过去的几十年里，儿童、青少年和成人的肥胖患病率增加了几倍。一些证据表明，中心性肥胖水平有不成比例的增加，它比外周脂肪带来更大的疾病风险。过去几十年饮食和运动习惯的变化无疑与当前超重和肥胖的流行有关，饮食质量和组成的变化也可能起作用。最近，人们开始关注环境化学污染物也可能导致肥胖问题日益严重的可能性。实验室研究的有限证据表明，合成化学物质可能通过改变激素水平或改变基因表达来影响与肥胖相关的途径，但实际上尚未进行人体研究。在这项拟议的流行病学研究中，将分析1999-2002年全国健康与营养调查（NHANES）中约5000名6岁及以上参与者的横断面数据，以确定血液和尿液中的环境污染物水平是否与体脂水平有关。要检查的体脂测量包括体重指数、腰围、肩胛下皮肤褶皱、体脂的数量和类型，使用双能x线吸收仪（DXA）估计。这项研究将检查接触邻苯二甲酸盐和重金属的潜在不利影响，以及植物雌激素（如基因素）对全身脂肪和中枢肥胖水平的可能保护作用。这些环境暴露与年龄，性别，各种饮食因素，活动水平之间潜在的重要相互作用也将被研究。最后，该研究还包括了一项二次分析，该分析利用了40多年来NHANES反复进行的调查，以回答在调整BMI增加后，中枢性肥胖水平在不同年龄、种族和性别亚组中是否随时间而增加的问题。本研究旨在利用现有数据探索一种新的假设，即环境污染物可能在一定程度上导致儿童和成人总肥胖率的上升和内脏脂肪沉积的增加。该研究的优势包括样本量大，血液和尿液中环境污染物的最先进测量，BMI的精确测量，dxa衍生的中心性肥胖测量，以及关于潜在混杂因素和影响调节剂的广泛信息。这项研究受到其横断面性质的限制。尽管如此，它可能为未来这些环境污染物对肥胖风险影响的流行病学研究提供重要线索。

DESCRIPTION (provided by applicant): The prevalence of obesity has increased several-fold over the last few decades in children, adolescents, and adults. Some evidence suggests that there has been a disproportionate increase in the level of central adiposity, which carries an even greater disease risk than peripheral fat. Changes in diet and exercise habits over the past few decades are undoubtedly linked to the current epidemic of overweight and obesity, and changes in the quality and composition of the diet may also play a role. Recently, interest has emerged in the possibility that environmental chemical contaminants may also contribute to the growing problem of obesity. Limited evidence from laboratory studies suggests that synthetic chemicals may affect obesity- related pathways by changing hormone levels or altering gene expression, but virtually no human studies have been conducted. In this proposed epidemiologic study, cross-sectional data on a sample of approximately 5000 participants, aged 6 years and older, from the 1999-2002 National Health and Nutrition Examination Survey (NHANES) will be analyzed to determine whether blood and urine levels of environmental contaminants are associated with level of body fat. The measures of body fat to be examined include body mass index, waist circumference, subscapular skin folds, and the amount and type of body fat, estimated using dual-energy x-ray absorptiometry (DXA). The study will examine the potential adverse effects of exposure to phthalates and heavy metals as well as the possible protective effects of phytoestrogens such as genestein on total body fat and the level of central adiposity. Potentially important interactions between these environmental exposures and age, gender, various dietary factors, activity levels will also be examined. Finally, the study includes a secondary analysis that takes advantage of the repeated NHANES surveys over four decades to answer the question of whether the level of central adiposity has increased over time in separate age, race, and gender subgroups, after adjusting for increases in BMI. This study is designed to use existing data to explore the novel hypothesis that environmental contaminants may, in part, be responsible for the increasing rates of total obesity and the increases in visceral fat deposition in children and adults. The strengths of the study include its large sample size, state-of-the-art measurements of environmental contaminants from blood and urine, precise measurements of BMI, DXA-derived measures of central adiposity, and extensive information on potential confounders and effect modifiers. The study is limited by its cross-sectional nature. Nevertheless, it may provide important clues for future, epidemiologic studies of the effect of these environmental contaminants on the risk of obesity.