Tobacco use, alcohol consumption and infertility.

An epidemiological study of the association between alcohol consumption, tobacco use and subfecundity is presented. Study subjects were recruited for a case-control study whose primary objective was to examine the association between occupational exposures and subfecundity. All 1069 women treated for infertility at Odense University Hospital during the period 1977-1980 were eligible for participation as cases. A control group was chosen consisting of 4305 women who had each delivered a healthy child with a gestational age over 258 days at the same hospital in the period 1977-1979. Data regarding occupational exposures and smoking and drinking habits were collected by mailed questionnaires. A response rate of 87% was obtained for both case and control groups. Use of tobacco and alcohol was significantly higher in cases compared to controls. A within-group comparison of alcohol consumption among controls with delayed conception of more than one year with controls who conceived their children within one year failed to demonstrate a statistical association. However, a statistically significant association was observed between smoking and delayed conception among controls. On the basis of this finding, along with further analyses, the authors suggest that the statistical association between smoking and subfecundity may be real and ought to be studied further. Moderate alcohol consumption does not seem to play a role in the development of subfecundity. The paper provides a systematic review of possible sources of bias in the study.