Secular trends in cancer mortality among Japanese immigrants in the state of Sao Paulo, Brazil, 1979-2001

We investigated secular trends in cancer mortality among first-generation Japanese-Brazilians in the state of Sao Paulo between 1979 and 2001. Results were compared with those for Japanese living in Japan and Brazilians living in the state of Sao Paulo. We used mortality data for three periods, 1979-1981, 1989-1991, and 1999-2001, and population data from Brazilian censuses in 1980,1991, and 2000 for Japanese-Brazilians. Available mortality and population data for Japanese living in Japan and Brazilians living in the state of Sao Paulo corresponding to those for Japanese-Brazilians were obtained. Age-standardized mortality rates for Japanese-Brazilians and standardized mortality ratios based on mortality of Japanese living in Japan in 1980 for the three different periods and populations were calculated. We observed a decreasing trend for stomach cancer and increasing trends for colon, breast and prostate cancer over the 20 years in all three populations. Standardized mortality ratios for stomach cancer in Japanese-Brazilians declined to approximately those of Japanese living in Japan. Although standardized mortality ratios from colon, breast and prostate cancer in Japanese-Brazilians increased over the last 20 years, those for colon cancer were similar to the Japanese living in Japan whereas those for breast and prostate cancer (208 and 423 in 2000, respectively) appeared to be intermediate between those for Japanese living in Japan (152 and 208 in 2000, respectively) and Brazilians living in the state of Sao Paulo (281 and 536 in 2000, respectively). Standardized mortality ratios for liver and lung cancer increased in Japanese living in Japan over the last 20 years but no increasing trend was observed for Japanese-Brazilians, except for liver cancer in men, and standardized mortality ratios in Japanese-Brazilians seemed to be similar to the Brazilians living in the state of Sao Paulo. Secular trends in mortality confirm the relative importance of environment in the development of cancer.