Risk factors for clinically diagnosed uterine fibroids in women around menopause

Objective: We analysed the risk factors for clinically diagnosed uterine fibroids in women attending menopause clinics in Italy. Methods: Between 1997 and 2003 we conducted a large cross-sectional study on the characteristics of women around menopause attending a network of first-level outpatient menopause clinics in Italy for general counselling about menopause or treatment of menopausal symptoms. A total of 85,967 non-hysterectomized women not reporting myomectomy entered the study; 2239 had a diagnosis of uterine fibroids. A woman was defined as having uterine fibroids if she had at gynecological examination an enlarged uterus (2 months of gestation or more) and a clinical diagnosis of fibroids. In 769 cases was performed in ultrasound examination which confirmed the diagnosis. Results: In comparison with women with a body mass index (BMI) <22, the multivariate ORs for BMI 26 or more were 1.30 (95% CI, 1.09-1.55) for cases with clinical diagnosis, and 1.29 (95% CI, 1.01-1.45) for women with ultrasonographic diagnosis. In comparison with premenopausal women, the multivariate OR for clinically detected fibroids was 0.63 (95% CI, 0.55-0.72) for post-menopausal ones. The risk of fibroids was lower in parous women than in nulliparous ones, and the risk decreased with number of births regardless the type of diagnosis. Conclusion: This study confirms in a large sample that parity is the main protective factor for the development of fibroids. Overweight increases the risk.