Background: Only a few studies on the mortality of Japanese immigrants have been conducted in Brazil despite a large population of Japanese immigrants and their different environment and lifestyle from Japanese living in Japan.
Methods: To compare cancer mortality between Japanese in Japan and Japanese immigrants or Brazilians in the state of São Paulo, Brazil, we obtained official death certificates registered during 1999-2001. The standardized mortality ratio (SMR) or the standardized proportional mortality ratio (SPMR) of major cancer sites was calculated for the first generation of Japanese immigrants to Brazil (Japan-born), their Brazil-born Japanese descendants, and native Brazilians using mortality data of Japanese in Japan as a standard.
Results: The SMRs of stomach and colorectal cancer did not differ between the Japan-born residents of Brazil and the native Japanese, but significantly low SMRs were found among the native Brazilians. Compared with the native Japanese, we observed significantly lower SMRs for liver, gallbladder and lung cancer and significantly higher SMRs for prostate, cervical, and brain and nervous system cancer among both the Japan-born residents of Brazil and the Brazilians. Generally, the SPMR results were similar to those of the SMRs. Significantly high SPMRs for breast and uterine cancer were found for both the Japan- and Brazil-born residents of Brazil, although the Japan-born residents had increased SMRs, but not significantly so.
Conclusions: We confirmed the different cancer mortality pattern in the Japanese immigrants from that in Japanese in Japan, thus demonstrating the relative importance of the environment in the development of cancer.