Chemical exposures and leukemia risk

90%的儿童白血病病因不明。许多研究表明，超级基金场址的环境暴露，如杀虫剂、金属、溶剂、多氯联苯（PCBs）和多芳烃（PAHs），可能会增加患儿童白血病的风险。然而，这些关联是基于父母报告或职业暴露。该提案提供了一个特殊的机会，通过直接测量环境和化学暴露来评估环境暴露的相互作用，评估环境暴露与遗传易感性的相互作用，并增加样本量和研究入组时间，扩展现有的在旧金山湾和中央山谷地区进行的儿童白血病病例对照研究。大约30-40%的联合研究人群将是西班牙裔。目前，正在实施三层接触评估中的两层。一级登记和访谈病例和控制，以确定疾病的风险因素，包括住宅和职业化学品接触。在第2层，根据特定标准没有改变居住地的病例和出生证明控制（约占第1层研究人口的50%）是可靠性研究的一部分，该研究旨在确定在面谈时自我报告的化学品是否在面谈后几个月的视觉调查中被发现。当前提案的重点是第3层，旨在通过在参与第2层的病例和对照者的一小部分家庭中对地板表面的灰尘取样，记录家庭暴露的可能性。目的是确定病例和对照者家中的农药、金属、多芳烃、可丁宁、多氯联苯和乙烯硫脲的浓度是否存在差异。此外，个案分析将确定有兴趣染色体易位的病例是否生活在目标化合物浓度较高的家庭中，而不是没有这种易位的病例。这些分析将确定具有共同遗传变化的白血病儿童是否经历共同的暴露，以及这些遗传变化是否具有大致相同的时间发生。此外，我们将评估白血病患儿和非白血病患儿在白血病易感性方面是否存在差异。

The causes for 90% of childhood leukemias are unknown. Many studies suggest that environmental exposures of concern at Superfund sites, such as pesticides, metals, solvents, polychlorinated biphenyls (PCBs), and polyaromatic hydrocarbons (PAHs), may increase the risk of developing childhood leukemia. However, these associations are based on parental reports or occupational exposures. This proposal provides a special opportunity to extend an existing case-control study of childhood leukemia being conducted in the San Francisco Bay and Central Valley areas by directly measuring environmental and chemical exposures, evaluating the interaction of environmental exposures by directly measuring environmental and chemical exposures, evaluating the interaction of environmental exposures with genetic susceptibility, and increasing the sample size and duration of study enrollment. Approximately, 30-40% of the combined study population will be Hispanic. Currently, two of three tiers of an exposure assessment are being implemented. Tier 1 enrolls and interviews cases and controls seeking to identify risk factors for the disease, including residential and occupational chemical exposures. In Tier 2, cases and birth certificate controls that have not changed residence based on specific criteria (approximately 50% of the Tier 1 study population) are part of a reliability study, which seeks to determine if self reported chemicals used at the time of interview are found in the home during a visual survey several months after interview. The focus of the current proposal, Tier 3, aims to document the potential for household exposures by sampling dust on the floor surfaces in a subset of homes of cases and controls participating in Tier 2. The objective is to identify if there are differences in concentrations of pesticides, metals, polyaromatic hydrocarbons, cotinine, polychlorinated biphenyls, and ethylenethiourea in the homes of cases and controls. Further, a case-case analysis will identify if cases with chromosomal translocations of interest life in homes with higher concentrations of target compounds than cases that do not have such translocations. These analysis will determine whether leukemic children with common genetic changes experience common exposures and whether these genetic changes have approximately the same temporal occurrence. Further, we will evaluate whether children with and without leukemia differ with respect to susceptibility to leukemia.