An ecological study of trends in cancer incidence and dietary changes in Hong Kong.

Cancer incidence rates from the Hong Kong Cancer Registry show significant increases in lung and colon cancers and decreases in nasopharyngeal cancer in both sexes from 1973 to 1992. Moreover, cervical cancer and male esophageal cancer have declined significantly, and changes in the trends of cancer of the following sites were of borderline significance: decreasing male laryngeal and female esophageal cancers and increasing prostate and female breast cancers. These changes have occurred along with dietary shifts in the population, from a diet predominantly of rice and small portions of meat, vegetables, and fish to one with larger portions of all foods but rice and eggs. The latter data were gathered from six government household surveys from 1963-64 to 1994-95. By combining the two data sets, correlation coefficients were calculated for per capita consumption patterns of eight foods (rice, pork, beef, poultry, saltwater fish, freshwater fish, fresh vegetables, and eggs) and cancer incidence data of the same year or 10 years later. Higher meat intakes were significantly and positively correlated with cancers of the colon, rectum, prostate, and female breast. The correlations also suggested that current diets were more influential than diets a decade before for cancers of the lung, esophagus, rectum, and prostate. Cancers of the nasopharynx and colon were significantly correlated with current and past diets. These results support the hypothesis that intakes of meat and its associated fat are risk factors for colon, rectal, prostate, and female breast cancers.