COHORT STUDY OF DIETARY SUPPLEMENTS AND CANCER RISK

维生素和矿物质补充剂是美国最常用的药物之一。无论是化学预防试验还是观察性研究都没有确定补充使用的益处或风险。这项建议的目的是调查补充维生素C、维生素E、钙和多种维生素的摄入量与癌症总发病率之间的关系。为了实现这一目标，将在华盛顿州西部的13个县招募一组人，平均随访2又1/4年。将向30万名年龄在50-74岁之间的男女发送邮件，使用从商业邮件列表中获得的姓名，其中将包括针对补充用户的招聘信和一份问卷。招募程序已经过测试，将产生35,000名男性受访者和40,000名女性受访者，其中75%的受访者在过去10年内至少使用过一种膳食补充剂。问卷询问了过去10年补充剂使用的详细信息，以及可能与补充剂使用和未来癌症风险相关的协变量信息（例如，病史，癌症风险因素，癌症筛查，补充剂使用的原因）。调查问卷还包括一份食物频率调查问卷，其中附加了关于补充食品的项目。2-4个月后，第二次邮寄给受访者将提供用于人体测量的卷尺和用于收集脸颊细胞DNA的刷子。将进行研究，以量化我们的主要暴露措施的相对有效性。通过将参与者标识符与华盛顿SEER癌症登记系统和华盛顿州死亡磁带连接起来，将有效和准确地收集终点信息。这些文件附件区域的外迁将通过与国家地址变更磁带的链接进行监测。该队列的长期随访将调查补充剂与特定癌症（肺癌、前列腺癌、乳腺癌和大肠）和总死亡率的关系，并将调查基因与补充剂的相互作用。如果补充剂有害或没有作用，这一信息对大量服用补充剂的美国人来说是很重要的。如果发现了有益的效果，就可以转化为成本效益高的癌症控制措施。

Vitamin and mineral supplements are among the most commonly used drugs in the U.S. Neither chemoprevention trials nor observational studies have established the benefits or risks of supplemental use. The aim of this proposal is to investigate the association of intake of supplemental vitamin C, vitamin E, calcium and multivitamins with total cancer incidence. To meet this aim, a cohort will be recruited within the 13 counties of western Washington State, and followed for a mean of 2 1/4 years. A mailing will be sent to 300,000 men and women age 50-74 using names obtained from a commercial mailing list, which will include a recruitment letter targeting supplemental users and a questionnaire. The recruitment procedures have been tested, and should yield 35,000 male respondents and 40,000 female respondents with 75% of respondents having used at least one dietary supplement in the prior 10 years. The questionnaire solicits detailed information on supplement use over the last 10 years, and information on covariates that may be associated with supplement use and with future risk of cancer (e.g., medical history, cancer risk factors, cancer screening, reasons for supplement use). The questionnaire also incorporates a food frequency questionnaire, with additional items on supplemented foods. A second mailing to respondents 2-4 months later will supply a tape measure for anthropometric measures and brushes for collection of DNA from cheek cells. Studies to quantify the relative validity of our primary exposure measures will be conducted. Endpoint information will be efficiently and accurately collected by linking participant identifiers to the system Washington SEER cancer registry and the Washington State death tapes. Out-migration from the attachment areas of these files will be monitored by linkage to the National Change of Address tape. Longer term follow-up of this cohort will allow the investigation of the association of supplements with specific cancers (lung, prostate, breast and large bowel) and with total mortality, and will allow investigation of gene-supplement interactions. If supplements are harmful or of no use, this information would be important for the large number of Americans taking supplements. If a beneficial effect is found, it could be translated into highly cost effective cancer control measures.