Does lifecourse socioeconomic position influence racial inequalities in the incidence of uterine leiomyoma? Evidence from the Pró-Saúde Study, Brazil

INTRODUCTION: Studies conducted in the USA 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 lifecourse socioeconomic adversity. The aim of this study was to investigate whether lifecourse socioeconomic position (SEP) mediates the association between skin color/race and incidence of UL.

METHODS: From 1999 through 2013, 906 premenopausal female civil servants with intact uteri and no history of medical diagnosis of UL of the Pró-Saúde cohort study in Rio de Janeiro, Brazil, were followed to determine their risk of having a medical diagnosis of UL during that period. The exposure of interest was self-classified color/race (whites: 496, browns: 217, blacks: 197). Lifecourse SEP was determined by parental education (early life SEP), participant education (SEP in early adulthood) and their combination (cumulative SEP). Gynecological exams and health insurance status were considered markers of access to health care. Hazard ratios (HR) and 95% confidence intervals (95%CI) were estimated using Cox proportional hazards models.

RESULTS: The incidence of UL was 23.9%(n=116) for whites, 27,9% (n= 55) for blacks and 32,7% (n= 71) for brown. Compared with whites, black and brown women had higher risk of reporting a new medical diagnosis of UL, respectively, HR: 1.2, 95%CI: 0.9-1.7; HR: 1.4, 95%CI: 1.1-1.9. Estimates were virtually identical in models including different variables related to lifecourse SEP.

CONCLUSIONS: This Brazilian study corroborated previous evidence of higher risk of developing uterine leiomyomas among women with darker skin color, and further suggest that lifecourse socioeconomic position adversity does not influence this association.