Cancer incidence in Norwegian Seventh-Day Adventists 1961 to 1986. Is the cancer-life-style association overestimated?

Standardized incidence ratio for cancer in Norwegian Seventh-Day Adventists compared with the general population was not significantly different from unity (men 91, women 97). Persons converting late in life had a higher incidence than those converting at an earlier age. Respiratory cancers (standardized incidence ratio [SIR] 59, 95% CI = 36 to 91) and cancers with an unspecified site (SIR 53, 95% CI = 25 to 97) were rarer and cancer of the uterine corpus (SIR 164, 95% CI = 109 to 237) was more common in Seventh-Day Adventists before the age of 75 years. Inclusion of all registered Seventh-Day Adventists regardless of religious activity and the relatively low cancer incidence rates in the Norwegian population could contribute to the nonsignificant result with regard to total cancer. Main etiologic factors in cancer development in Norway should be sought in areas where Seventh-Day Adventists do not differ from the general population.