Smoking habits and endometriosis risk among infertile women: Results from a case control study

Some studies have suggested that tobacco smoking may affect the risk of endometriosis, but published data are controversial. We conducted a case control study on the association between smoking and endometriosis risk Cases of endometriosis included 90 women (median age 35, range 19-49) with incident, i.e. laparoscopically diagnosed within the year before interview, histologically confirmed endometriosis. Controls were 90 women (median age 35.5, range 17- 76) admitted for a wide spectrum of acute conditions unrelated to known potential risk factors for endometriosis. Compared with never smokers the OR of endometriosis was 2.36 (95% CI 1.04-5.35) in ever smokers. These findings were largely consistent in strata of age and education. Considering separately nulliparous and parous women the estimated OR of endometriosis in ever smokers were 1.51 (95%CI 0.26-11.36) and 2.52. In conclusion despite the limitations of this study the present analysis suggest that smoking may increase the risk of endometriosis in nulliparae women attending an infertility clinic: this finding may at least in part due to the effect of smoking on infertility.