Association between oral health and upper respiratory tract infection among children

Abstract

Background The oral cavity is a potential reservoir for respiratory pathogens. This longitudinal study investigated the association between upper respiratory tract infection (URI) and oral health among children.

MethodsA total of 288 children aged 4 years were recruited. Their dental caries and oral hygiene status were clinically determined, using the dmft (decayed, missing and filled teeth) index and the Silness-Loe plaque index. Questionnaires were completed by parents to collect information on the child's socio-demographic background and URI episodes and symptoms in the following 12 months. Standard or zero-inflated negative binomial regressions were used to analyse the association between URI and both oral health indicators (dmft and plaque score).

Results Some 138 (47.9%) children had URI in 12 months, including 63 (21.9%) and 75 (26.0%) children with 1-2 episodes and 3 episodes, respectively. The reported URI episodes fell into two peaks, coinciding with the two influenza peaks in Hong Kong. Significantly a higher dmft was found among children without URI compared with children who had 3 URI episodes (1.32 vs. 0.49; P = 0.043). The number of URI episodes was inversely associated with dmft (IRR = 0.851; 95% CI: 0.766-0.945; P = 0.003). There was no significant association between the plaque score and URI (P > 0.05).

Conclusions The children's caries experience was associated with reduced episodes of URI. Whether this inverse association is attributed to the immune response induced by dental caries is yet to be investigated.