Chemical exposures and leukemia risk

90%的儿童白血病的原因是未知的。许多研究表明，在超级基金的网站，如农药，金属，溶剂，多氯联苯（PCB）和多环芳烃（PAH）的关注环境暴露，可能会增加儿童白血病的风险。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品暴露，通过直接测量环境和化学品暴露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，并增加研究招募的样本量和持续时间。大约30-40%的合并研究人群将是西班牙裔。目前，正在实施三个接触评估层次中的两个。第1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暴露。在Tier 2中，基于特定标准（约占Tier 1研究人群的50%）未改变居住地的病例和出生证明对照是可靠性研究的一部分，该研究旨在确定在访谈时使用的自我报告化学品是否在访谈后几个月的目视调查中在家中发现。 当前提案的重点是Tier 3，旨在通过对参与Tier 2的病例和对照家庭的地板表面上的灰尘进行采样，记录家庭暴露的可能性。其目的是确定是否有农药，金属，多环芳烃，可替宁，多氯联苯，和乙烯利在案件和控制的家庭浓度的差异。此外，病例-病例分析将确定具有感兴趣的染色体易位的病例是否生活在目标化合物浓度高于不具有这种易位的病例的家庭中。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率。此外，我们将评估是否有白血病和非白血病儿童在白血病易感性方面存在差异。

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.