# Associations of Fecal Microbiota with Ectopic Fat in African Caribbean Men

## TL;DR

This study explores how gut bacteria in African Caribbean men relate to fat accumulation in areas like the liver and heart, finding links between certain microbes and higher fat levels.

## Contribution

The study provides new insights into gut microbiota associations with ectopic fat in African-ancestry men, a population underrepresented in prior research.

## Key findings

- Lower gut microbiota diversity was linked to higher visceral and ectopic fat accumulation.
- Gram-negative bacteria like Prevotellaceae were positively associated with fat accumulation, while Ruminococcaceae showed inverse associations.
- BMI and visceral fat explained similar levels of variation in gut microbiota composition.

## Abstract

Objective: The gut microbiome has been associated with visceral fat (VAT) in European and Asian populations; however, associations with VAT and with ectopic fats among African-ancestry individuals are not known. Our objective was to investigate cross-sectional associations of fecal microbiota diversity and composition with VAT and ectopic fat, as well as body mass index (BMI), among middle-aged and older African Caribbean men. Methods: We included in our analysis n = 193 men (mean age = 62.2 ± 7.6 years; mean BMI = 28.3 ± 4.9 kg/m2) from the Tobago Health Study. We assessed fecal microbiota using V4 16s rRNA gene sequencing. We evaluated multivariable-adjusted associations of microbiota features (alpha diversity, beta diversity, microbiota differential abundance) with BMI and with computed tomography-measured VAT and ectopic fats (pericardial and intermuscular fat; muscle and liver attenuation). Results: Lower alpha diversity was associated with higher VAT and BMI, and somewhat with higher pericardial and liver fat. VAT, BMI, and pericardial fat each explained similar levels of variance in beta diversity. Gram-negative Prevotellaceae and Negativicutes microbiota showed positive associations, while gram-positive Ruminococcaceae microbiota showed inverse associations, with ectopic fats. Conclusions: Fecal microbiota features associated with measures of general adiposity also extend to metabolically pernicious VAT and ectopic fat accumulation in older African-ancestry men.