Epidemiological factors of cancer in California.

California has 12% of the U.S. population. In 1991, the newly diagnosed cancer cases in California represented 10% of all new cancer cases in the country, and the yearly toll was 10% of all cancer deaths. Relative to all new cancer cases in the U.S., California had 10, 9.8, 9.8, and 9.3% of breast, lung, prostate, and colorectal cancers, respectively. Because of its large population and cancer incidence, the epidemiology of cancer in California is of particular interest. Epidemiological factors reviewed in this article include ethnicity, lifestyle, occupation, and environmental conditions. Ethnic factors: There is an increased incidence of cervical and gallbladder cancer among Hispanic women, and of stomach cancer in Hispanic men and women. In U.S.-born Chinese men, the most prevalent cancers are those of the lung and colon, which is also seen in American white men. In U.S.-born Chinese women, there is an upward displacement of breast cancer incidence. In U.S.-born Japanese men and women, the mortality rate is closer to that of American whites. Life-style: Members of the Mormon Church and Seventh-Day Adventists have only 50% of the U.S. standardized mortality rate for cancer associated with smoking. Increased coffee consumption has been found to be associated with increased occurrence of colon and bladder cancer; alcohol use has been reported to have a positive association with colorectal cancer. The large AIDS population in San Francisco has a 144-fold odds ratio of Kaposi's sarcoma and a fivefold odds ratio of lymphoma when compared with the general U.S. population. Occupational factors: An increased incidence of mesothelioma in asbestos workers, of gastric cancer, skin cancer, and lymphoma in men working in dusty environments, and of astrocytoma in individuals with prolonged exposure to low-frequency electric and magnetic fields has been recorded. Environmental factors: The drinking-water pool in northern California is contaminated with asbestos of the serpentine type, which is associated with mesothelioma of the peritoneum and carcinoma of the lung, gallbladder, and pancreas. Petrochemical fumes in the heavily industrialized San Francisco Bay area have not been associated with an increased occurrence of cancer. No significant incidence in cancer has been noted in the counties surrounding the nuclear power plant at San Onofre during 18 years of close observation.