Colorectal cancer incidence in Asian migrants to the United States and their descendants.

OBJECTIVES

To examine the incidence of colorectal cancer among Asian residents of the United States according to country of birth.

METHODS

We determined the incidence of colorectal cancer during 1973-1986 among Asian residents in three areas of the western United States (Hawaii, San Francisco/Oakland SMSA, and western Washington state) in relation to country of birth. Numerators for the rates were obtained from the Surveillance, Epidemiology and End Results (SEER) program; a special tabulation of the 1980 US Census was used to estimate the size and composition of the population at risk.

RESULTS

US-born Japanese men experienced incidence rates of colorectal cancer twice as high as foreign-born Japanese men and about 60% higher than those of US-born white men. Incidence among US-born Japanese women was about 40% higher than that among Japanese women born in Japan or US-born white women. Foreign-born Chinese men had about the same incidence of colorectal cancer as US-born white men, while US-born Chinese men experienced slightly reduced rates. Chinese women had rates that were generally 30-40% lower than that of US-born white women, regardless of place of birth. Incidence rates for both US-born and foreign-born Filipinos were 20-50% those of US-born whites.

CONCLUSIONS

These findings suggest that one or more exposures or characteristics that differ between Japanese migrants and their descendants affect the development of colorectal cancer.