Racial and ethnic differences in uterine fibroid prevalence in a diverse cohort of young asymptomatic women (18-30 yo)

Abstract

While there is an abundance of data on fibroid prevalence and age of onset in Caucasian (CW) and African American (AAW) women, there are very few data on these parameters in Hispanic (HW), East Asian (EAW) and South Asian (SAW) women. The current study aims to determine potential differences in the prevalence of fibroids and related uterine parameters in a cohort of racially and ethnically diverse women of Hispanic, East-Asian and South Asian origin (ages 18-30). Prospective cross-sectional study. Participants underwent either a trans-vaginal (TVUS) or abdominal ultrasound (AUS) during the follicular phase (days 4-11) of their menstrual cycle. Ultrasounds scans were read by a single expert. Size, location and dimensions of visible fibroids, endometrial thickness (sagittal cut), uterine size and ovarian volume were measured. Chi-square and analysis of variance (ANOVA) were used to determine differences between groups. 177 women participated in this ultrasound study (mean age 24.3, SD 3.5 years), of which 58 (32.8%) self-identified as CW, 43 (24.3%) as AAW, 34 (19.2%) as EAW, 24 (13.6%) as HW and 18 (10.2%) as SAW. The data on CW and AAW have been previously reported and are being used as comparative controls (1). The mean cycle day of assessment for all women was 8.2 ± 2.0 days. The overall fibroid prevalence was 10.7% (TVUS: 92%; AUS:8%). Fibroids were significantly more common among AAW than in other racial/ethnic groups (CW: 7.5%; AAW: 25.5%; EAW: 5.8%; HW: 4.2%; SAW: 5.5%; p= 0.025). Overall average fibroid size (measured by largest diameter) was 2.0 cm ± 1.9 cm (CW: 1.7 cm ± 1.4 cm; AAW: 2.4 cm ± 2.3 cm; EAW: 1.7 cm ± 0.1 cm; HW: 0.8 cm; SAW: 1.3 cm; p=0.88). Comparisons of uterine volume (CW: 41.1 cc ± 14.6 cc; AAW: 64.5 cc ± 62.3 cc; EAW: 47.9 cc ± 15.0 cc; HW: 47.0 cc ± 13.3 cc; SAW: 39.3 cc ± 10.9 cc ; p=0.008), endometrial thickness (CW: 4.3 mm ± 2.4 mm; AAW: 6.0 mm ± 2.8 mm; EAW: 5.1 mm ± 1.9 mm; HW: 5.3 mm ± 2.0 mm; SAW: 4.8 mm ± 1.7 mm; p=0.01), right ovarian volume (CW: 5.5 cc ± 3.5 cc; AAW: 10.4 cc ± 12.2 cc; EAW: 5.1 cc ± 2.9 cc; HW: 5.8 cc ± 3.3 cc; SAW: 5.8 cc ± 2.1 cc; p=0.002) and left ovarian volume (CW: 4.5 cc ± 2.6 cc; AAW: 6.2 cc ± 3.9 cc; EAW: 5.9 cc ± 3.8 cc; HW: 6.1 cc ± 4.9 cc; SAW: 8.9 cc ± 12.1 cc ; p=0.04) revealed statistically significant differences amongst groups. This study suggests that there are significant ethnic differences in fibroid prevalence and related uterine anatomy even in asymptomatic women. Expanding on previous work, we found that when compared to other groups, fibroid prevalence and size remained the highest among AAW. Rates in EAW and SAW were similar to those found in CW. Rates and sizes were lowest among HW, which could indicate later age of onset and/or a different pathophysiology. Comparisons of uterine anatomy also showed that AAW had significantly larger ovarian volumes and thicker endometrium. Collectively, these results warrant an exploration of ethnic-specific consideration when developing treatment options for patients with fibroids.