Authors:

Toshihide Tsuda, Graduate School of Environmental Life Sicence, Okayama University , Japan, tsudatos@md.okayama-u.ac.jp
Etsuji Suzuki, Graduate School of Medical, Dental and Pharmaceutical Science, Japan, eee9687@gmail.com
Eiji Yamamoto, Okayama University of Science, Japan, eiji@mis.ous.ac.jp
Background: After the accident in the Nuclear Power Plant, Fukushima Prefecture planned thyroid cancer screening for all children aged 18 years or younger. The present report is based on the data until December 31, 2013. Methods: We divided Fukushima Prefecture into the following seven areas: (a) “Nearest area” (i.e., the most contaminated area); (b) “North middle”; (c) “Central middle”; (d) Koriyama city; (e) “South middle”; (f) Iwaki city; and (g) “Eastern least contaminated area”. Among the areas (b) to (e) (i.e., “Middle area”), “Central middle” has the highest air dose rate and “North middle” and “South middle” have the lowest. The areas (f) and (g) correspond to the “less affected location” in the WHO report. We calculated prevalence odds ratios (PORs) for thyroid cancer by using the area (g) as a reference. As an external comparison, we estimated incidence rate ratios (IRRs) in each area, compared with the annual incidence estimate of thyroid cancer among those aged 15 to 19 (i.e., 5 per 1,000,000), which is based on the data from the Japanese National Cancer Center. In so doing, we assumed two years of duration on clinically detectable level of cytology. Results: We show the results of PORs and IRRs in Table. Conclusions: In both internal and external comparisons, we observed excess thyroid cancer cases in Fukushima, 2 years and 10 months after the accident. Both further investigations and countermeasures against the suspected adverse health effects are necessary in Fukushima and neighboring areas.
Figure/Table:

Filename:2086.pdf
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