Is dental caries associated with lower respiratory tract infections?

Design This study comprised an analysis of data from a cohort, born in the Finnish city of Espoo between January 1 1984 and March 31 1990.Objectives The objective of the study was to investigate the effect of dental caries on the risk of lower respiratory tract infections (LRTI) in participants aged 20-27, using data collected during the 20-year follow-up conducted in 2010-2011.Data Dental caries experience was determined by asking study participants 'Estimate, how many teeth with a filling you have?' LRTI was defined as at least one occurrence in the 12 months prior to the administration of the 20-year questionnaire. LTRI data were obtained by asking participants if they had suffered from influenza or pneumonia, bronchitis, bronchiolitis or unspecified lower respiratory tract infection. In addition, data were obtained from the National Hospital Discharge Register. Risk ratios were determined using Poisson regression models.Results Having a high number of filled teeth was associated with an increased number of LRTIs (adjusted relative risk 1.24) and was not modified by the family's socioeconomic status or by smoking.Conclusions The authors suggest that dental caries increases the risk of LRTIs, but concede that common risk factors might explain at least partly the observed relation between filled teeth and LRTIs.