Association between Residential Greenness and Human Microbiota: Evidence from Multiple Countries

Area of Science:

• Environmental health
• Microbiome research
• Global health

Background:

• Greenness, or vegetated land density, is linked to health, but its effect on the human microbiome is understudied.
• Existing evidence is limited by region, sample size, and inconclusive findings.

Purpose of the Study:

• To investigate the association between residential greenness exposure and human microbial diversity and composition.
• To analyze data from a large, multinational sample (34 countries) to understand global patterns.

Main Methods:

• Assessed greenness using Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI).
• Employed linear regression for alpha-diversity and permutational multivariate analysis of variance (PERMANOVA) for composition.
• Utilized DESeq2 for differential abundance analysis of microbial genera.

Main Results:

• Increased greenness correlated with higher microbial richness in palm and gut samples.
• Gut microbiota evenness decreased with higher greenness exposure.
• Specific genera like *Lactobacillus* and *Bifidobacterium* were more abundant, while *Anaerotruncus* and *Streptococcus* were less abundant with higher greenness.

Conclusions:

• Residential greenness is associated with human skin and gut microbial richness and composition across diverse global settings.
• Findings suggest a link between environmental greenness and the human microbiome, warranting further investigation into health outcomes.