Ultrasound-Confirmed, Age-Specific Uterine Leiomyoma Incidence in a Cohort of Black Individuals

Abstract

Objective: To estimate the age-specific incidence of uterine leiomyomas identified by transvaginal ultrasonography among participants in SELF (Study of Environment, Lifestyle & Fibroids).

Methods: SELF is a longitudinal cohort study of individuals aged 23-35 years who self-identified as Black. Participants were recruited from the Detroit, Michigan, area and underwent up to five transvaginal ultrasonograms over a period of up to 10 years to identify uterine leiomyomas. We randomly imputed incidence dates between the last ultrasonogram date in which no leiomyomas were detected and the date of the ultrasonogram in which leiomyomas were first detected. We used Poisson regression to estimate age-specific incidence rates per 1,000 person-years with 95% CIs. The rates were then compared with those of the BWHS (Black Women's Health Study) and the NHS II (Nurses' Health Study II)-two prospective cohort studies based on self-reported leiomyoma diagnoses.

Results: In this cohort, 1,693 participants completed a baseline interview and ultrasonogram. We excluded 385 (22.7%) participants with leiomyomas detected during baseline, seven participants whose ultrasonograms were poor quality, and 60 participants with only a baseline ultrasonogram. Among the remaining 1,241 participants, the overall incidence rate was 53.9 cases per 1,000 person-years (95% CI 48.6-59.6). The age-specific incidence rates (cases/1,000 person-years) were: younger than 30 years: 49.7, 95% CI 40.9-59.9; 30-34 years: 55.2, 95% CI 47.0-64.3; and 35-39 years: 58.2, 95% CI 47.3-70.9. Among participants aged younger than 30 years, the incidence rate in SELF was more than double that of the BWHS or the NHS II.

Conclusion: The high age-specific leiomyoma incidence rates in this prospective ultrasound-based study indicate that many young Black individuals with leiomyomas go undiagnosed. These data suggest that individuals could benefit from ultrasound screening when they experience symptoms compatible with leiomyomas (eg, heavy menstrual bleeding, anemia, pelvic pain).

Figure 1.

Study participant flow chart.

Figure 2.

Incidence rate of leiomyoma cases identified by ultrasonography or hysterectomy per 1,000 person years. Study of Environment, Lifestyle and Fibroids (SELF) is the only study that screened all participants for leiomyomas with ultrasonography. BWHS, Black Women’s Health Study; NHS II, Nurses’ Health Study II.