American Journal of Epidemiology Advance Access originally published online on November 13, 2007
American Journal of Epidemiology 2008 167(3):271-279; doi:10.1093/aje/kwm295
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ORIGINAL CONTRIBUTIONS |
Reproductive History and Mortality in Late Middle Age among Norwegian Men and Women
1 Centre for Population Studies, Department of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, United Kingdom
2 Department of Economics, University of Oslo, Oslo, Norway
Correspondence to Dr. Emily Grundy, Centre for Population Studies, Department of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, 49-51 Bedford Square, London WC1B 3DP, United Kingdom (e-mail: Emily.grundy{at}lshtm.ac.uk).
Received for publication June 5, 2007. Accepted for publication September 17, 2007.
There is growing recognition that reproductive patterns may have long-term health implications, although most evidence is restricted to women. The authors used register data to derive fertility histories for all Norwegian men and women born in 1935–1958. Discrete-time hazard modeling was used to analyze later-life mortality by aspects of reproductive history. A total of 63,312 deaths were observed during 14.5 million person-years of follow-up in 1980–2003, when subjects were aged 45–68 years. Models included detailed information on educational qualifications and marital status. Odds of death relative to those for subjects with two children were highest for the childless (women: odds ratio (OR) = 1.50, 95% confidence interval (CI): 1.43, 1.57; men: OR = 1.35, 95% CI: 1.30, 1.40) and next highest for those with only one child (women: OR = 1.31, 95% CI: 1.26, 1.37; men: OR = 1.20, 95% CI: 1.16, 1.24). Results for the parous showed a positive association between earlier parenthood and later mortality, a reverse association with late age at last birth, and an overall negative association between higher parity and mortality. The similarity of results for women and men suggests biosocial pathways underlying associations between reproductive history and health. The lack of any high-parity disadvantage suggests that in the "family friendly" Norwegian environment, the health benefits of having several children may outweigh the costs.
men; middle aged; mortality; Norway; parity; registries; reproductive history; women
Abbreviations: CI, confidence interval; OR, odds ratio