Cancer incidence among California Seventh-Day Adventists, 1976-1982.

Cancer incidence was monitored in a population of 34,000 Seventh-day Adventists in California. By religious belief, Adventists do not consume tobacco, alcohol, or pork and approximately one-half adhere to a lacto-ovovegetarian lifestyle. Only a small percentage are pure vegetarians. Comparisons of cancer-incidence rates in this population with an external reference population were completed by calculating standardized morbidity ratios (SMRs) for all cancer sites. Also, within the population, relative risks were calculated by using data obtained from a detailed lifestyle questionnaire that members of the study population completed. For all cancer sites combined in males, the SMR was lower in the Adventists (SMR = 0.73). The SMR was also lower in males for most individual cancer sites. However, prostate cancer risk was higher. For females, the all-cancer SMR was lower but not significantly so (SMR = 92). Most site-specific SMRs were lower, although not as much as the male SMRs. The SMR for endometrial cancer was significantly higher in female Adventists.