RESUMO
BACKGROUND: Uterine fibroids (UFs) are the most common neoplasm affecting women that can cause significant morbidity and may adversely impact fertility. OBJECTIVES: To examine UF epidemiology and to evaluate the relative strengths of putative risk factors. SEARCH STRATEGY: MEDLINE and Embase were searched for studies published in English between January 1995 and April 2015. SELECTION CRITERIA: Publications reporting relevant data from registries and other observational studies with over 1000 patients and single-centre studies with over 100 patients were selected. DATA COLLECTION AND ANALYSIS: Data on UF incidence, prevalence and associated risk factors were extracted from 60 publications. MAIN RESULTS: Wide ranges were reported in both UF incidence (217-3745 cases per 100 000 women-years) and prevalence (4.5-68.6%), depending on study populations and diagnostic methods. Black race was the only factor that was recurrently reported to increase UF risk, by two-threefold compared with white race. Eleven other factors affected UF risk to a magnitude similar to or greater than race. Age, premenopausal state, hypertension, family history, time since last birth, and food additive and soybean milk consumption increased UF risk; use of oral contraceptives or the injectable contraceptive depot medroxyprogesterone acetate, smoking in women with low body mass index and parity reduced UF risk. CONCLUSIONS: We identified 12 risk factors that play an important role in UF epidemiology. The UF risk factor with the strongest evidence is black race. High-quality prospective observational data are needed to improve our understanding of UF epidemiology, and thus its aetiology and optimal management. TWEETABLE ABSTRACT: Uterine fibroids occur in about 70% of women. Black race and 11 other factors affect uterine fibroid risk.