Air Pollution and Oral Health in the European Union: Preventive System Capacity as a Structural Modifier of Caries...

Background/Objectives: Environmental air pollution and structural barriers to preventive dental care are increasingly recognized as determinants of population health inequalities. However, their combined association with oral disease burden across European Union (EU) Member States remains insufficiently examined. This study evaluated whether ambient particulate matter (PM2.5) exposure is associated with oral health outcomes and whether preventive system capacity modifies this association. Methods: An ecological panel analysis was conducted using country-level data from the 27 EU Member States for the period 2020-2023. Age-standardized prevalence of untreated dental caries (primary outcome), edentulism (secondary outcome), and periodontal diseases (exploratory outcome) were obtained from the Global Burden of Disease database. PM2.5 exposure was operationalized using national mean annual baseline values. Preventive care access was proxied by the percentage of the population reporting unmet dental care needs (Eurostat EU-SILC). Pooled panel regression models with year fixed effects and country-clustered robust standard errors were estimated. An interaction term between PM2.5 exposure and unmet dental care needs was included to assess effect modification. Results: PM2.5 exposure was not independently associated with caries prevalence after adjustment for preventive access and GDP per capita. However, a statistically significant interaction was observed: higher PM2.5 levels were associated with increased caries prevalence in countries reporting greater unmet dental care needs. PM2.5 exposure was positively associated with edentulism prevalence, independent of preventive access. No significant associations were detected for periodontal diseases. Conclusions: Based on this ecological analysis of European Union Member States, higher PM2.5 exposure in combination with greater unmet dental care needs was associated with higher population-level caries prevalence, whereas PM2.5 exposure alone showed a positive association with edentulism prevalence. These findings are exploratory and should be interpreted with caution, given the use of aggregated country-level data, the potential for ecological fallacy, and the absence of causal inference. Further individual-level and longitudinal studies are needed to clarify these relationships and their underlying mechanisms.