Risk factors for adenomyosis.

In order to analyse risk factors for adenomyosis, 707 consecutive women who underwent hysterectomy between January 1993 and June 1994 at the Clinica Luigi Mangiagalli, Milan, Italy, were interviewed before surgery by trained physicians. Information on the presence of adenomyosis was obtained from pathologic records. Out of the 707 women, adenomyosis was identified in 150 subjects (21.2%). Women who smoked tended to be at decreased risk of the condition: in comparison with women who had never smoked, the risk for current smokers was 0.7 (0.3-1.3) and the risk decreased with number of cigarettes smoked per day, the odds ratios being 0.8 and 0.6 respectively in women reporting fewer than 10 and more than 10 cigarette smoked per day (chi2 trend 3.57, P = 0.06). The frequency of adenomyosis was higher in parous women: in comparison with nulliparae, the odds ratio of the disease were 1.8 [95% confidence interval (CI) 0.9-3.4] and 3.1 (95% CI 1.7-5.5) respectively in women reporting one and two or more births (chi2 trend 20.71, P < 0.01). Likewise, women reporting one or more spontaneous abortions had an odds ratio of 1.7 (95% CI 1.1-2.6) for adenomyosis, in comparison with those reporting no spontaneous abortion.