Skin microbiome alpha diversity of young children in association with surrounding green space

The skin microbiome plays a crucial role in maintaining skin health by influencing immune responses and protecting against pathogens. Previous research showed that green space was associated with e.g., a lower risk of infantile atopic dermatitis. To date, the relationship between early-life exposure to green space and the skin microbiome in young children remains unstudied.

403 children aged 4 to 12 from the birth cohort ENVIRONAGE participated in this study. After wetting Floq swabs with a drop of sterile saline, the swab was rubbed on the forehead for a minute to collect skin bacteria. We performed bacterial 16s rRNA gene sequencing via 16S Pacbio HiFi to calculate alpha diversity indices (observed richness, Chao1 richness, ACE richness, species evenness, Shannon diversity, and Simpson diversity). Green space (total green, high green, and low green) was estimated in several radius distances (100 m to 2000 m) around their current residence and school based on high-resolution land cover data. We used generalized linear models to examine the associations between green space and alpha diversity indices. Results are expressed as the change in alpha diversity per interquartile range increment in green space.

In childhood, positive associations were found between surrounding total green and high green and all three skin microbial richness indices: observed richness, Chao1 richness, and ACE richness in multiple radius distances. In general, stronger associations were found in smaller radius distances: e.g., each interquartile range (IQR) increment in total green in a 300 m radius was associated with an increase of 17.01 (p = 0.01) in observed richness, while each IQR in total green in a 2000 m radius was associated with an increase of 13.64 (p = 0.08) in observed richness.

We found that total green and high green in different radius distances were positively associated with skin microbial richness in young children.