Background: Thyroid cancer incidence in New York State has increased rapidly in recent years, particularly in New York City and its surrounding metropolitan area. In 2007 among white non-Hispanics, incidence rates were about 40% higher in the New York City metropolitan area than in the rest of the state. Here we explore the extent to which living in neighborhoods with a high percentage of highly observant Jews may be associated with this pattern.
Methods: We identify neighborhoods with concentrations of highly observant Jewish persons based on the use of Yiddish among children and the location of Orthodox synagogues. Thyroid cancer risk is modeled as a function of living in such a neighborhood, adjusting for age, sex, and other factors. The model was repeated for small (<2 cm) and large (≥2 cm) tumors to assess the role of diagnostic improvements in driving the spatial-temporal patterns.
Results: A moderate association with thyroid cancer was found among those living in Jewish neighborhoods and downstate New York. A lesser association was found among those who live in neighborhoods of high levels of people born in Russia, Belarus, or Ukraine. Similar elevated rate ratios were seen for small and large tumors in Jewish neighborhoods, providing evidence against differences in diagnostic practices in this group. Smaller tumors were more pronounced among women and persons diagnosed more recently.
Conclusions: The associations found do not seem to be diagnostically driven, but rather due to environmental, genetic, or cultural factors in the highly observant population of New York State.