HIV Infection and its association with Caries and the Salivary Microbiota in Nigerian children aged 6 to 72 months

Abstract

Background: Studies have shown that HIV infected individuals are more likely to present with dental caries suggesting a disruption in the oral microbiome with declining immune status. However, the association between HIV infection/exposure, caries and salivary bacterial composition and diversity in young Nigerian children has not been established in literature. Objectives: The objectives of this study were to compare 1) prevalence of caries and 2) bacterial diversity indices in HIV infected (HI) and HIV exposed but uninfected (HEU) children with HIV unexposed and uninfected (HUU) children Methods: These groups of study participants were examined orally to determine prevalence of caries. Saliva samples were collected and analyzed to determine microbiota diversity (specifically Shannon diversity indices) and composition using high-throughput 16S rRNA gene sequencing. Demographic, birth/delivery, clinical, diet and oral hygiene information were collected through a standardized questionnaire. Results: Compared to HUU children, HI children were more likely to present with caries and other oral diseases. After controlling for significant confounders, we observed significantly higher odds of caries in the HI group compared to the HUU group. HEU children had higher, but not significant, odds for caries within adjusted analyses. Other factors significantly associated with higher caries prevalence include older age, long duration of breastfeeding, low CD4 counts and percentage, and spontaneous membrane rupture during delivery. Although HEU children had lower microbial diversity indices, they did not significantly differ across study groups; however, young age and poor immune status were significantly associated with lower diversity indices within an adjusted analysis. We observed some minor but significant differences in the salivary microbial composition across study groups. Conclusions: Study findings support the growing evidence that HIV infected children are at an increased odds of presenting with caries and other oral diseases even when receiving antiretroviral treatment. We found that immune status plays a stronger role in influencing salivary bacterial composition and diversity, possibly affecting caries risk in this population of Nigerian children. There is need to further explore the responses of the oral microbiota to changes in the immune system over time as well as the influence of birth/delivery factors.