Association between short-term exposure to ambient air pollution and outpatient visits for pulpitis in Hefei, China: a time series study

Evidence suggests a possible association between ambient air pollutants and oral diseases. Nevertheless, information regarding the relationship between air pollutants and pulpitis is scarce and inconclusive. In view of this, the present study aimed to investigate the relationship between short-term exposure to air pollution and outpatient visits for pulpitis. Daily data on outpatient visits for pulpitis, air pollutants, and meteorological data in Hefei, China, was collected from January 1, 2015 to December 31, 2021. The association between exposure to air pollutants and pulpitis outpatient visits was evaluated using distributed lag non-linear model (DLNM) and a generalized linear model (GLM). Furthermore, stratified analyses were performed by gender, age and season. A total of 93,324 records of outpatient visits for pulpitis were included in this study. The results showed that exposure to NO2, PM2.5, and CO were positively correlated with an increased risk of pulpitis outpatient visits. Each 10 μg/m3 increase in NO2 and PM2.5 concentration, at lag 0–2 day, was associated with a 2.4% (relative risk (RR) = 1.024, 95% confidence interval (CI): 1.014–1.035) and 0.5% (RR = 1.005, 95% CI: 1.000–1.010) increase in pulpitis outpatient visits, respectively. With a 1 mg/m3 increase in CO concentration, the risk of pulpitis outpatient visits increased by 9.1% (RR = 1.091, 95% CI: 1.031–1.154, lag 0–1 day). Intriguingly, exposure to O3 was associated with a decreased risk of pulpitis outpatient visits (RR = 0.990, 95% CI: 0.984–0.995, lag 0–5 day). Subgroup analysis revealed that in the warm season, exposure to PM2.5, O3, and CO was related with a significantly higher outpatient risk of pulpitis than in the cold season. Additionally, the influence of PM2.5 and CO exposure at age < 65 years was significantly stronger than at age ≥ 65 years. In conclusion, exposure to ambient NO2, PM2.5, and CO is associated with an increase in pulpitis outpatient visits in Hefei, China. Conversely, exposure to O3 reduces the risk of outpatient visits for pulpitis. Age and season are effect modifiers of these associations.