Bacterial Community Modifies Host Genetics Effect on Early Childhood Caries

Area of Science:

• Oral Health
• Microbiology
• Genetics

Background:

• Early childhood caries (ECC) affects approximately 20% of children by age 5.
• Both oral microbiome and host genetics are implicated in ECC susceptibility.
• The interplay between the oral microbiome and genetic predisposition to ECC remains largely unexplored.

Purpose of the Study:

• To investigate whether the salivary bacteriome modifies the association between genetic susceptibility (polygenic score) and ECC in a longitudinal birth cohort.
• To determine the independent and interactive effects of genetic risk and salivary bacterial community state types (CSTs) on ECC development.

Main Methods:

• A polygenic score (PGS) for primary tooth decay was constructed using genome-wide association data.
• Poisson regression was used to assess the association between PGS and ECC incidence.
• Salivary bacteriome data (24 months) and ECC status (60 months) were analyzed for effect modification by bacterial community state types (CSTs).

Main Results:

• A high PGS was not significantly associated with increased ECC incidence.
• Cariogenic salivary bacterial CSTs at 24 months were strongly associated with ECC by 60 months (OR, 7.48).
• A significant interaction (P=0.04) was observed between salivary bacterial CST and PGS, where PGS was associated with ECC only in children with non-cariogenic CSTs.

Conclusions:

• The oral microbiome plays a critical role in modifying genetic susceptibility to ECC.
• Genetic risk for ECC may be masked or amplified by the oral microbiome composition.
• Targeting and preventing colonization by cariogenic oral microbiomes could be a universally beneficial strategy for ECC prevention across varying genetic risk profiles.