What are the primary risk factors for developing uterine fibroids?

Primary Risk Factors for Developing Uterine Fibroids

Black race is the strongest and most consistently identified risk factor for developing uterine fibroids, with Black women having a two to threefold higher risk compared to white women and developing fibroids at an earlier age. 1, 2

Demographic and Genetic Risk Factors

• Race/Ethnicity:

  • Black women have >80% cumulative incidence by age 50, compared to ~70% in white women 1, 3
  • Black women develop fibroids earlier (peak at 35-39 years vs. 40-44 years in white women) 1
  • Black women have more numerous fibroids, larger tumors, and heavier uterine weight 1

• Age:

  • Risk increases with age during reproductive years 1, 4
  • Peak incidence occurs in the perimenopausal period 1
  • Risk decreases after menopause (70-90% reduced risk) 1

• Family history:

  • Positive family history significantly increases risk 2, 5
  • Suggests genetic predisposition to fibroid development

Hormonal and Reproductive Risk Factors

• Hormonal status:

  • Premenopausal state significantly increases risk 1, 2
  • Postmenopausal women have 70-90% reduced risk due to decreased ovarian function 1

• Reproductive history:

  • Nulliparity increases risk 1
  • Longer time since last birth increases risk 2
  • Early menarche may increase risk (inconsistent evidence) 1

• Hormonal medications:

  • Oral contraceptives and depot medroxyprogesterone acetate may reduce risk 2
  • Hormone replacement therapy increases risk in postmenopausal women 5

Lifestyle and Medical Risk Factors

• Body composition:

  • Obesity is strongly associated with fibroid development 1, 5
  • Being overweight increases risk 5

• Hypertension:

  • Associated with increased risk of fibroids 2
  • May share common pathophysiological mechanisms

• Diet and consumption habits:

  • Alcohol consumption increases risk 2, 5
  • Food additives and soybean milk consumption may increase risk 2
  • Vitamin D deficiency may increase risk, particularly in women of African descent 3

• Other lifestyle factors:

  • Smoking may reduce risk, particularly in women with low BMI 2
  • Diabetes is associated with decreased risk 5

Associated Gynecological Conditions

• Gynecological disorders:
  • Polycystic Ovary Syndrome (PCOS) 1
  • Endometriosis 1
  • Menstrual disorders 1

Clinical Implications and Pitfalls

• Fibroids are often asymptomatic, with only approximately 25% of women showing clinical symptoms despite high prevalence 3

• Rapid growth of fibroids warrants investigation for potential malignancy, particularly in perimenopausal women 4

• Failure to recognize racial disparities may lead to delayed diagnosis and treatment, especially in Black women who develop fibroids earlier and with greater severity 1

• The economic burden of symptomatic fibroids is substantial, ranging from $5.9 to $34.4 billion annually 1

Understanding these risk factors is crucial for early identification of women at high risk, appropriate screening, and timely intervention to reduce morbidity and improve quality of life in women with uterine fibroids.