Studies of other risk factors for radiosensitive tumors

在过去的30年里，美国甲状腺癌的发病率一直在上升，其原因在很大程度上是未知的。我们一直在对5项NCI前瞻性研究进行汇总分析，研究该疾病的潜在危险因素。这个汇集项目提供了一些迄今为止最有力的证据，表明肥胖可能是甲状腺癌的一个危险因素，因此肥胖率的上升可能是甲状腺癌发病率上升的部分原因。我们现在正在扩大这个汇集项目，纳入来自15个欧洲和美国队列的数据，以更详细地研究这种关系，包括与中心性肥胖相关的风险以及肥胖与罕见甲状腺癌亚型之间的关系。NCI队列联盟BMI汇总项目-我们从20项前瞻性研究和150多万人中建立了生活方式风险因素和死亡率数据的丰富数据集，以研究BMI与全因死亡率之间的关系。2010年发表的详细分析结果表明，最佳BMI在20-25之间。我们目前正在探索腰围和全因死亡率之间的关系，并扩大汇集项目，以研究包括甲状腺和胆囊在内的罕见癌症的发病率。由于病例数量有限，这些癌症通常难以在单个队列中进行研究。儿童癌症在中国儿童和家庭队列中的研究-我们正在进行两项试点研究，以测试以下两种方法的可行性：(1)跟踪和参与对来自两个县的500个家庭样本的访谈，这些县在20世纪90年代中期实施了社区干预计划（CIP）；(2)确定1994- 1996年在为CIP人群服务的医院出生的儿童中发生的儿童癌症事件，以及将这些儿童癌症患者与CIP联系起来的能力人口。CIP社区干预项目试验于1994- 1996年在北京东北部和南部的三个大县进行，评估了孕产期叶酸补充剂在减少神经管缺陷方面的有效性。在围孕期服用叶酸补充剂的母亲的后代中，神经管缺陷的发生率显著降低。过去10年西方国家病例对照流行病学研究的出版物表明，孕产期叶酸补充剂可以降低服用叶酸补充剂的母亲的后代患儿科白血病和其他儿科癌症的风险。其他研究表明，叶酸与孕产期叶酸和后代其他严重慢性疾病（包括哮喘）有统计学关联。试点研究将试图追踪、招募和采访500个来自江苏太仓和河北乐亭的家庭，并试图确定1994年至目前在1994-96年出生的儿童中诊断出的所有儿童癌症，并将这些儿童与CIP队列联系起来。

Thyroid cancer incidence rates have been increasing for the last 3 decades in the US and the reasons for this are largely unknown. We have been studying potential risk factors for the disease in a pooled analysis of 5 NCI prospective studies. This pooling project provided some of the strongest evidence to date that obesity may be a risk factor for thyroid cancer and the rising obesity rates could therefore be part of the explanation for the rise in thyroid cancer incidence rates. We are now expanding this pooling project to include data from 15 European and US cohorts to examine the relationship in more detail including the risk associated with central adiposity and the relationship between obesity and rarer thyroid cancer subtypes.NCI Cohort Consortium BMI Pooling Project - We built a rich dataset of lifestyle risk factor and mortality data from 20 prospective studies and over 1.5 million people to study the relationship between BMI and all cause mortality. The results from this detailed analysis published in 2010 suggested that optimal BMI was in the range 20-25. We are currently exploring the association between waist circumference and all cause mortality, and expanding the pooling project to look at cancer incidence for rare cancers including thyroid and gallbladder. These cancers are typically difficult to study in individual cohorts because the numbers of cases is limited.Childhood Cancer In Chinese Children and Family Cohorts -We are conducting two pilot studies to test the feasibility of (1) follow and participation in interviews of a sample of 500 families from two county sites where the Community Intervention Program (CIP) was carried out in the mid-1990s and (2) identification of incident pediatric cancers arising among thoseborn during 1994-96 in hospitals serving the CIP population and ability to link these pediatric cancer patients back to the CIP population. The CIP community intervention program trial, which was carried out during 1994-96 in three large counties northeast and south of Beijing, evaluated the effectiveness of periconceptional folic acid supplements in reducing neural tube defects. There were dramaticreductions in neural tube defects among offspring of mothers who took folic acid supplements during thepericonceptional period. Publications from case-control epidemiologic studies in the past 10 years from Western countries have shown that periconceptional folic acid supplements may reduce risks of pediatric leukemia and potentially other pediatric cancers in offspring of mothers who take these supplements. Otherstudies have shown statistical associations with periconception folic acid and other serious chronic diseasesof offspring including asthma. The pilot studies will attempt to trace, enroll, and interview 500 families fromTaicang, Jiangsu Province and Laoting, Hebei Province and will seek to identify all pediatric cancers diagnosedduring 1994 to the present among children born during 1994-96 and link these children back to the CIP cohort.