||5R01CA063284-04 Interpret this number
||Cancer Prevention Instit Of California
||Thyroid Cancer in a Multiethnic Population
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.
Iodine And Thyroid Cancer Risk Among Women In A Multiethnic Population: The Bay Area Thyroid Cancer Study
, Morris J.S.
, Lee M.
, West D.W.
, Whittemore A.S.
, McDougall I.R.
, Nowels K.
, Stewart S.L.
, Spate V.L.
, Shiau A.C.
, et al.
Cancer Epidemiology, Biomarkers & Prevention : A Publication Of The American Association For Cancer Research, Cosponsored By The American Society Of Preventive Oncology, 2001 Sep; 10(9), p. 979-85.