THYROID CANCER IN A MULTIETHNIC POPULATION

这项以人群为基础的流行病学研究将探讨以下因素的作用： 营养因素和妇女甲状腺癌风险的移徙， 特别强调亚裔美国人，这是一个高风险人群。 甲状腺 癌症是年轻女性中最常见的癌症之一， 在迅速增长的亚裔美国人中。发生率较高 美国的亚洲移民中甲状腺癌的发病率比 亚洲土著人口，表明容易变化的环境 暴露，如营养因素，在后期阶段起作用， 致癌过程中，影响甲状腺癌的风险。 有限的生态， 实验和流行病学证据表明，高碘暴露 可能会增加甲状腺乳头状癌的风险， 美国的组织学类型。 另外，一些研究结果 归因于高水平的碘暴露可能是由低水平的碘暴露引起的。 硒消耗 增加其他抗氧化剂的消耗也可能 在降低甲状腺癌风险方面发挥作用。 病例对照研究 一项旨在阐明这些关联的研究将在旧金山进行。 弗朗西斯科湾区，一个种族和文化异质的人口 从而提供饮食摄入的实质性变化。 被诊断患有 将在三年期间前瞻性地确定甲状腺癌。 此外，为了检验与移民有关的假设， 在过去的三年里，将被追溯识别。 对照组将是从一般人群中选出的女性概率样本。 人口使用随机数字拨号，频率匹配的情况下， 根据五岁年龄组和种族/民族（即，非西班牙裔白色， 非裔美国人、西班牙裔/拉丁裔、亚裔美国人）。 所有受试者将 诊断时年龄在20岁至74岁之间，居住在北方五个城市， 加州县由两个基于人口的癌症登记处覆盖。 个人采访将用英语，西班牙语， 广东话、越南语或越南语。 由于土壤中的碘含量和 硒变化很大，强烈影响食物水平，这些摄入量 来自食物频率问卷的微量元素受 严重的分类错误 因此，剪下的脚趾甲， 这些微量元素的一个相对长期的生物标志物 在致癌作用的促进阶段， 收集并使用中子活化分析进行分析。 肿瘤综述 将对病例进行标本采集，以验证恶性程度，并提供 统一的组织学分类。 在对数据进行初步检查后， 非条件logistic回归分析，调整年龄和 种族/民族，将进行测试营养假设。 关于移民的假设将在亚裔美国人中进行检验。

This population-based epidemiologic study will examine the role of nutritional factors and migration in thyroid cancer risk among women, with special emphasis on Asian Americans, a high risk population. Thyroid cancer is one of the most commonly occurring cancers among young women and in the rapidly growing population of Asian Americans. The higher incidence of thyroid cancer among Asian immigrants to the United States than among native Asian populations, suggests that readily changeable environmental exposures, such as nutritional factors, acting at a late stage in the carcinogenic process, affect thyroid cancer risk. Limited ecologic, experimental, and epidemiologic evidence suggests that high iodine exposure may increase the risk of papillary thyroid cancer, the most common histologic type in the United States. Alternatively, some of the findings attributed to high levels of iodine exposure may be explained by low selenium consumption. Increased consumption of other antioxidants may also play a role in decreasing thyroid-cancer risk. The proposed case-control study, designed to clarify these associations, will be conducted in the San Francisco Bay Area, an ethnically and culturally heterogenous population providing substantial variation in dietary intake. Women diagnosed with thyroid cancer will be prospectively identified during a three-year period. In addition, to test hypotheses related to migration, Asian cases diagnosed during the preceding three years will be retrospectively identified. Controls will be a probability sample of women selected from the general population using random-digit dialing, frequency-matched to cases on the basis of five-year age-groups and race/ethnicity (i.e., non-Hispanic White, African American, Hispanic/Latina, Asian American). All subjects will be between the ages of 20 and 74 at diagnosis and reside in five northern California counties covered by two population-based cancer registries. Personal interviews will be conducted with subjects in English, Spanish, Cantonese, Tagalog, or Vietnamese. Since soil levels of iodine and selenium vary widely and strongly influence food levels, intake of these trace elements derived from food-frequency questionnaires are subject to substantial misclassification. Therefore, toenail clippings, which provide a relatively long-term biologic marker of these trace elements correlated with exposure during the promotional phase of carcinogenesis, will be collected and analyzed using neutron activation analysis. Review of tumor specimens will be undertaken for cases to verify malignancy and provide a uniform histologic classification. After initial examination of the data, unconditional logistic regression analyses, adjusting for age and race/ethnicity, will be conducted to test nutritional hypotheses. Hypotheses regarding migration will be tested among Asian Americans.