Epidemiologic evidence of perinatal influence in the etiology of adult cancers

Using data from 5489 cancer patients and 2647 patients without cancer we investigated whether parental age at the birth of the patient or the patient's rank within his sibship was related to the risk of cancer during adulthood. An increase of 10 years in maternal age was associated with an increase of 24% for the incidence of breast cancer (odds ratio = 1.24; 95% CI = 1.09-1.41); the corresponding increase for paternal age was 19% (odds ratio = 1.19; 95% C1 = 1.07-1.33). There was some evidence that the age of each parent may make an independent contribution to the risk of breast cancer. For certain types of genito-urinary cancers, the risk was higher when the parents were relatively young at the birth of the patient. These cancers included tumors arising in the prostate (odds ratios = 0.71 and 0.55 for maternal and paternal ages, respectively), testis (odds ratios = 0.57 and 0.52), penis (odds ratios = 0.37 and 0.45), kidney (odds ratios = 0.66 and 0.60), and bladder (odds ratio = 0.79 and 0.85). The associations for cancer of the prostate and bladder were stronger among patients who were diagnosed at a relatively young age. No statistically significant effects were found for birth order relative to adult cancers. The authors conclude that environmental factors that affect the parents or that operate in the perinatal period may have stronger influences on the incidence of adult cancers than have been previously recognized.