Cancer risk, age at diagnosis, and age at death as functions of season of birth.

The Third National Cancer Survey (TNSC) includes more than 90,000 patients who died during the study period. Their lifespan varies with their season of birth. Patients born in the winter became in average 1.5 years older than patients born in the summer. This difference is very significant. The variation agrees with the results from a similar study performed about 50 years ago which used genealogical data. The season of birth distributions are equal for males and females, slightly different for blacks and whites and different for colon, rectum, breast cancer patients compared to stomach and lung cancer patients. There are significant regional difference with greater variation in season of birth for patients residing in hot areas than for patients residing in cold areas. It is assumed that the observed phenomena are related to health in general and not to cancer in particular.