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，肥胖的流行率在儿童、青少年和成年人中增加了几倍。一些证据表明，中心性肥胖症的水平出现了不成比例的增加，这种肥胖症的患病风险甚至比外周脂肪更大。过去几十年饮食和锻炼习惯的变化无疑与当前超重和肥胖的流行有关，饮食质量和构成的变化也可能起到一定作用。最近，人们对环境化学污染物也可能导致日益严重的肥胖问题产生了兴趣。来自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，但几乎没有进行过人体研究。在这项拟议的流行病学研究中，将分析1999-2002年全国健康和营养检查调查(NHANES)中约5000名6岁及以上参与者的横断面数据，以确定环境污染物的血液和尿液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、肩峰下皮肤皱褶以及体脂的数量和类型，使用双能X射线吸收法(DXA)进行估计。这项研究将研究邻苯二甲酸盐和重金属暴露的潜在不利影响，以及植物雌激素(如Genstein)对全身脂肪和中心性肥胖水平的可能保护作用。还将研究这些环境暴露与年龄、性别、各种饮食因素和活动水平之间的潜在重要相互作用。最后，这项研究包括一个二级分析，它利用40年来重复的NHANES调查来回答这样一个问题，即在根据BMI的增加进行调整后，在不同的年龄、种族和性别亚组中，中心性肥胖水平是否随着时间的推移而增加。这项研究旨在利用现有数据来探索这一新的假设，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增加和内脏脂肪沉积的增加。这项研究的优势包括其庞大的样本量，最先进的血液和尿液环境污染物的测量，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效果修饰剂的广泛信息。这项研究受到其横截面性质的限制。然而，它可能为未来这些环境污染物对肥胖风险的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.