Introduction USA studies showed that uterine leiomyomas (UL) occur more frequently among black women, but the nature of this association remains largely unexplained. Because black women are disproportionately disadvantaged in social hierarchies, such racial inequality might be explained by life-course socioeconomic adversity.

Aim To investigate whether life-course socioeconomic position (SEP)—during childhood, early adulthood, or lifelong—is a mediator of associations between colour/race and UL among Brazilian women.

Methods We analysed data from self-administered questionnaires completed by 1534 female civil servants at a Rio de Janeiro university during the baseline data collection of the Pró-Saúde Study. Three study outcomes were explored: self-reported medical diagnosis of UL; UL with symptoms prior to diagnosis; and hysterectomy due to UL. The childhood SEP was assessed by parental education and the early adulthood SEP measured by participants' education; the cumulative SEP measures resulted from a combination of the previous information. We estimated ORs and 95% CIs by logistic regression models.

Results Compared to whites, black and brown (mixed race) women presented risks respectively 1.6 (95% CI 1.2 to 2.1) and 1.4 (95% CI 0.8 to 2.5) higher of UL. This estimate was higher for those submitted to hysterectomy due to UL (blacks—OR: 2.6 to 1.7; 4.0 and brown—OR: 1.1 to 0.9; 1.5). These estimates were not significantly altered in models including variables related to life-course SEP.

Conclusion In this Brazilian population, UL risk increased with the darkening of skin colour, and the life-course SEP did not mediate this association.