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Updated: Oct 4, 2025
Oral Biofilm Sampling for Microbiome Analysis in Healthy Children
Published on: December 31, 2017
Associations between PM2.5 exposure and infant growth: A mediation analysis of oral microbiota
Huaying Wu1, Chao Dong2, Wenwen Xiao2
1Department of Stomatology, Women's Hospital of Nanjing Medical University, Nanjing Maternity and Child Health Care Hospital, Nanjing 210004, China.
Background:
Previous studies have linked growth retardation with ambient fine particulate matter (PM2.5) exposure. However, few studies explored such association from the perspective of microbiota, such as oral microbiota. We aimed to identify the potential role of oral microbiota in the links between PM2.5 exposure and infant growth.
Methods:
Baseline information of 335 recruited mother-child pairs was collected by structured questionnaires. Growth indicators (weight, length) of one-year-old infants were abstracted from medical records when they had physical examination and corresponding z scores were calculated. 16S rRNA gene amplicon sequencing was performed to assess oral microbiota of infants and co-abundance groups (CAGs) were further calculated. We assessed PM2.5 levels by inverse distance weighting (IDW). Generalized linear regression and mediation analysis were performed to determine associations between PM2.5 exposure, oral microbiota and growth indicators.
Results:
Per 10 μg m-3 increment of PM2.5 in the period of 10th month-examination was associated with decreased length z score (β = -1.97, 95%CI: -3.83, -0.11). Oral microbiota correlated with weight z score and body mass index (BMI) z score was identified by Spearman correlation analysis. CAG4 was statistically associated with increased weight z score (β = 3.40, 95%CI: 0.29, 6.51) and BMI z score (β = 5.44, 95%CI: 1.00, 9.87). Several bacteria in the level of genus and CAG associated with PM2.5 exposure were additionally identified (P < 0.05). Mediation analysis revealed that PM2.5 in the period of birth-3rd month impacted the z scores of weight and BMI by altering relative abundance of Megasphaera (P < 0.05).
Conclusion:
PM2.5 exposure from 10th to 12th month after birth could retard infant linear growth. PM2.5 might impact oral microbiota of one-year-old infants. Growth-related bacteria and CAGs were identified. Megasphaera might function as mediator between PM2.5 exposure during birth-3rd month and infant z scores of weight and BMI.
Insights
Fine particulate matter (PM$_{2.5}$) exposure can stunt infant growth, potentially by altering oral microbiota. Specific bacteria and co-abundance groups (CAGs) were identified as mediators in this relationship.
Area of Science:
- Environmental Health
- Microbiology
- Pediatrics
Background:
- Previous research links fine particulate matter (PM$_{2.5}$) exposure to growth retardation in infants.
- The role of oral microbiota in this association remains underexplored.
- This study investigates the potential mediating role of oral microbiota in the relationship between PM$_{2.5}$ exposure and infant growth.
Purpose of the Study:
- To examine the association between ambient PM$_{2.5}$ exposure and infant growth indicators.
- To identify specific oral microbiota profiles associated with infant growth.
- To determine if oral microbiota mediates the effect of PM$_{2.5}$ on infant growth.
Main Methods:
- Collected baseline data from 335 mother-child pairs.
- Assessed infant growth (weight, length z-scores) and oral microbiota using 16S rRNA gene sequencing.
- Quantified PM$_{2.5}$ levels using inverse distance weighting and employed regression and mediation analyses.
Main Results:
- Increased PM$_{2.5}$ exposure (10th month-exam) was linked to decreased infant length z-scores.
- Specific oral microbiota, including CAG4, correlated with higher weight and BMI z-scores.
- PM$_{2.5}$ exposure (birth-3rd month) affected weight and BMI z-scores by altering the abundance of the bacterium *Megasphaera*.
Conclusions:
- PM$_{2.5}$ exposure during infancy can impede linear growth.
- PM$_{2.5}$ exposure may influence the oral microbiome composition in one-year-old infants.
- *Megasphaera* may act as a key mediator linking early-life PM$_{2.5}$ exposure to infant weight and BMI outcomes.
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