Number of children and death from hormone-dependent cancers.
The association between number of children of current marriage reported by 431,604 women aged 45-74 years at the Norwegian Census in 1970 and mortality, at follow-up through 1985, from hormone-dependent cancers, i.e., cancers of breast, corpus uteri and ovary combined, has been investigated. The reduction in age-adjusted mortality was 9.6% (95% confidence interval; 8.3-10.9%) for each child with no deviation from linearity. Women with 8-11 children had a relative risk of 0.34 (0.25-0.47) compared to nullipara. Adjustment for age at first birth slightly changed the effect of number of children on mortality to 9.3% per child. The reduction in mortality per child was for cancer of the breast 7.2%, corpus uteri 12.2% and ovary 12.7%. Our findings indicate that having few children is a major risk factor for death from the 3 hormone-dependent cancers combined.
Lund
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Institute of Community Medicine, University of Tromsø, Norway.
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000401:mortality*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008423:Maternal Age; D008875:Middle Aged; D009376:Neoplasms, Hormone-Dependent / Q000401:mortality*; D010051:Ovarian Neoplasms / Q000401:mortality*; D010298:Parity; D012306:Risk; D013223:Statistics as Topic; D002583:Uterine Cervical Neoplasms / Q000401:mortality*