Dental caries is associated with lower respiratory tract infections: A population-based cohort study.

INTRODUCTION: Dental caries and respiratory tract infections are among the most common infectious diseases worldwide and they both are appearing in the respiratory system. However, their relations are still unclear. This study investigated the association of dental caries on the risk of lower respiratory tract infections (LRTI) in young adulthood. METHODS: The study population consisted of 1,592 Finnish young adults participating in the 20-year follow-up of The Espoo Cohort Study. The information on the occurrence of LRTIs (pneumonia or acute bronchitis) during the preceding 12 months was based on the follow-up questionnaire and the National Hospital Discharge Register. Lifelong caries on permanent teeth was defined as a self-reported number of filled teeth (FT). The risk ratios (RR) of LRTIs with 95% confidence intervals (CI) were estimated using Poisson regression models. RESULTS: High FT number was associated with an increased occurrence of LRTIs with an adjusted RR of 1.24 per interquartile range (IQR) of FT (95% CI 1.06-1.44). The risk of LRTIs increased according to the increasing number of FTs, being highest among those subjects with 10 or more filled teeth (adjusted RR 2.30; 1.27-4.17). Family's socioeconomic status or smoking did not modify the effect. CONCLUSIONS: Our results suggest that dental caries increases the risk of LRTIs. We did not find any significant effect modification by shared determinants of caries and LRTIs. However, it is possible, that common risk factors might explain at least partly the observed relation between FT and LRTIs or that the causality is bidirectional.

Early Respiratory Infections and Dental Caries in the First 27 Years of Life: A Population-Based Cohort Study.

Early-life respiratory tract infections (RTIs) and dental caries are among the most common infectious diseases worldwide. The relations between early RTIs and development of caries in permanent teeth have not been studied earlier. We assessed childhood RTIs as potential predictors of caries in young adulthood in a 20-year prospective population-based cohort study (The Espoo Cohort Study). Information on lower respiratory tract infections (LRTIs) that had required hospitalization was retrieved from the National Hospital Discharge Registry (n = 1623). Additional information on LRTIs and upper RTIs (URTIs) was assessed based on the questionnaire reports that covered the preceding 12 months. Caries was measured as the number of teeth with fillings (i.e. filled teeth, FT) reported in the 20-year follow-up questionnaire. The absolute and relative excess numbers of FT were estimated applying negative binomial regression. The mean number of FT in young adulthood was 1.4 greater among subjects who had experienced LRTIs requiring hospitalization before the age of 2 years (SD 4.8) compared to those without any such infections (SD 3.4), and the adjusted relative excess number of FT was 1.5 (95% CI 1.0-2.2). LRTIs up to 7 years were associated with an absolute increase of 0.9 in the mean FT number, the adjusted relative excess being 1.3 (1.0-1.8). Also the questionnaire-based LRTIs (adjusted relative excess 1.3; 95% CI 0.9-1.8) and URTIs (adjusted relative excess 1.4, 1.0-1.8) before the age of 2 years predicted higher occurrence of FT. Findings suggest that early RTIs have a role in the development of dental caries in permanent teeth.