The Association Between Breast Density and Gut Microbiota Composition at 2 Years Post-Menarche: A Cross-Sectional Study of Adolescents in Santiago, Chile

• Published in: Frontiers in cellular and infection microbiology 2021-12, Vol.11, p.794610-794610
• Main Authors: Yoon, Lara S, Jacobs, Jonathan P, Hoehner, Jessica, Pereira, Ana, Gana, Juan Cristóbal, Corvalán, Camila, Michels, Karin B
• Format: Article
• Language: English
• Subjects: adolescence; Adolescent; breast cancer; Breast Density; Cellular and Infection Microbiology; Chile; Cohort Studies; Cross-Sectional Studies; epidemiology; Female; Gastrointestinal Microbiome; gut microbiota; human; Humans; Menarche; RNA, Ribosomal, 16S - genetics
• ISSN: 2235-2988; 2235-2988
• DOI: 10.3389/fcimb.2021.794610

The gut microbiome has been linked to breast cancer immune, inflammatory, and hormonal mechanisms. We examined the relation between adolescent breast density and gut microbial composition and function in a cohort of Chilean girls. This cross-sectional study included 218 female participants in the Growth and Obesity Cohort Study who were 2 years post-menarche. We measured absolute breast fibroglandular volume (aFGV) and derived percent FGV (%FGV) using dual energy X-ray absorptiometry. All participants provided a fecal sample. The gut microbiome was characterized using 16S ribosomal RNA sequencing of the V3-V4 hypervariable region. We examined alpha diversity and beta diversity across terciles of %FGV and aFGV. We used MaAsLin2 for multivariable general linear modeling to assess differential taxa and predicted metabolic pathway abundance (MetaCyc) between %FGV and aFGV terciles. All models were adjusted for potential confounding variables and corrected for multiple comparisons. The mean %FGV and aFGV was 49.5% and 217.0 cm , respectively, among study participants. Similar median alpha diversity levels were found across %FGV and aFGV terciles when measured by the Shannon diversity index (%FGV T1: 4.0, T2: 3.9, T3: 4.1; aFGV T1: 4.0, T2: 4.0, T3: 4.1). %FGV was associated with differences in beta diversity ( 0.012, =0.02). No genera were differentially abundant when comparing %FGV nor aFGV terciles after adjusting for potential confounders (q > 0.56 for all genera). We found no associations between predicted MetaCyc pathway abundance and %FGV and aFGV. Overall, breast density measured at 2 years post-menarche was not associated with composition and predicted function of the gut microbiome among adolescent Chilean girls.