Racial differences in mammographic density in Brazil: implications for mammographic screening. (30th September 2020)

• Record Type: Journal Article
• Authors: Gabrielli, L; Ghaderi, S; Almeida, M C C; Goes, E; Gnoatto, C; Almeida, L; Menezes, G M S; dos-Santos-Silva, I; Aquino, E M L
• Is Part Of: European journal of public health. Volume 30:Number 5(2020)
• Publication Date: 2020-09-30
• Subjects: Epidemiology -- Europe -- Periodicals; Public health -- Europe -- Periodicals; 362.109405
• DOI: 10.1093/eurpub/ckaa165.827
• Languages: English
• ISSNs: 1101-1262

Abstract

Abstract: Background: Mammographic density (MD)-the amount of radio-dense fibroglandular tissue seen on a mammogram - is a stronger biomarker of susceptibility to breast cancer and a major determinant of the sensitivity of mammographic screening. This study examined for the first time racial differences in MD in Brazil. Methods: 555 women (215 from the Longitudinal Study of Adult Health - ELSA-Brasil and 340 users of the Unified Health System - SUS) in Bahia were enrolled into the study. Participants completed an interview, had their heights and weights measured, and underwent a 2-view (cranio-caudal (CC) and medio-lateral-oblique (MLO)) digital mammography of each breast. MD was measured on the left MLO image using the semi-automated Cumulus software, and expressed as the percentage (PMD) of the breast area occupied by fibroglandular tissue. Linear regression models were fitted to assess ethnicity-PMD associations adjusting for age at mammography, body mass index (BMI) and reading batch (minimally-adjusted) and further for socio-economic and reproductive variables. Results: The study population comprised 95 White (W), 270 Brown-mixed (Bm) and 169 Black (B) women, with a mean age at mammography of 58 (SD = 5.4) years. 63% W, 69% Bm and 49% B women had low educational level; 24% W, 47% Bm and 31% B women had ≥4 children. Minimally-adjusted analysis showed that relative to W women, PMD was 23% (1.23; 95% CI 1.04-1.45) higher in Bm and 4% (1.04; 0.89-1.21) higher in B; however, further adjustment for socio-economic and reproductive variables attenuated the racial differences (fully-adjusted model: 16% (1.16; 0.96-1.40) and 9% (1.09; 0.92-1.29) for Bm and B, respectively. Conclusions: The racial differences in PMD were mainly accounted by ethnic differences in socio-economic and reproductive-related factors. Implications Further studies should examine whether racial differences in PMD in Brazil lead to racial differences in false negative and interval cancer rates of mammographic screening. Key messages: In Brazil, ethnic differences in socio-economic and reproductive-related factors are responsible for racial differences in mammographic density. More research is needed to address racial differences in breast cancer risk in Brazil.