BACKGROUND AND PURPOSE:

• May occur in up to 70% of women by menopause and will be clinically apparent in 25% of women of reproductive age
  • 25% of women will require treatment
• Stewart et al. (BJOG, 2017) is the first systematic review of epidemiology to assess the contribution of risk factors associated with fibroids

METHODS:

• Systematic search of papers related to risk factors, without specifically selecting for symptomatic or asymptomatic fibroids (1995-2015)
• Analyses were conducted on pooled data from relevant publications and registries
• Data on UF incidence, prevalence and associated risk factors were extracted from 60 publications

RESULTS:

• A wide range of both UF incidence (217-3,745 cases/100,000 women-years) and prevalence (4.5%-68.6%) were reported
  • No consistent associations between prevalence and country/region, study methodology or population were seen across the studies
• Black race compared to white race was the only factor consistently found to increase UF risk (2-3 fold increase)
• Owing to the large number of risk factors, researchers focused on risk factors for which the magnitude of the effect was approximately the same as or greater than the effect of race (i.e. 95% CI ≥1.5 for a risk factor or ≤0.67 for a protective factor)
  • Using this criterion, 11 other factors were identified
• Other factors that increased UF risk include
  • Age (up to 10-fold increase up until age 60)
  • Premenopausal state (3- to 5-fold)
  • Hypertension (SBP ≥ 140 mmHg; DBP ≥90 mmHg or current use of antihypertensive medication) had an almost fivefold increased risk)
  • Family history (3-fold)
  • Time since last birth (2-3 fold if gave birth > 5 years ago)
  • Food additives (processed, sweetened or preserved foods) and soybean milk consumption had a 2.5-fold greater risk
• UF risk was decreased using
  • Oral contraceptives (70% lower risk who currently use vs never use)
  • Injectable contraceptive depot medroxyprogesterone acetate (less than ½ as likely)
  • Smoking in women with low BMI
  • Parity (risk 1/5 of nulliparous if ≥ 3 deliveries)

CONCLUSION:

• This study identified 12 risk factors for fibroids, confirming race and age as primary risk factors
• This study did not address symptomatic vs non-symptomatic fibroids

Learn More – Primary Sources:

Epidemiology of uterine fibroids: a systematic review