Ambient Temperature and its Nonlinear Relationship with the Risk of Oral Disease: A Time-Series Study from Guangzhou

Abstract

Previous studies have noted a distinct seasonal variation in oral diseases, which appeared to align with the patterns of climate change. This observation sparked our interest in investigating whether there is a definitive correlation between ambient temperature fluctuations and the incidence of oral diseases in different climatic cities of China, a connection that, to date, remains unclear. This study aimed to elucidate the relationship between ambient temperature and the incidence of oral diseases. Daily outpatient data from the Affiliated Stomatological Hospital of Guangzhou Medical University spanning 2020 to 2022 were collected, and a time-series analysis was conducted. We fit the data utilizing a generalized additive model and a distributed lag nonlinear model, adjusting for factors such as relative humidity, time trends, day of the week, and holidays. Our evaluation focused on discerning the relationship between ambient temperature and oral diseases. We amassed a total of 206,729 outpatient oral disease patients. The results showed that low temperatures (below 12–13°C) correlated with a greater risk of oral diseases. In contrast, temperatures above 12–13°C appeared to have a negligible influence on oral ailments. Relative to our reference temperature, the cumulative risk factors for various oral diseases at low temperatures (8.9°C, 1st percentile) were as follows: dental caries (2.28; 95% CI: 1.69–3.08), periodontitis (1.92; 95% CI: 1.38–2.67), pulpitis (2.91; 95% CI: 2.0-4.23), periapical periodontitis (3.15; 95% CI: 2.06–4.82) and temporomandibular joint disorder syndrome (TMD) (1.63; 95% CI: 0.89–3.01). These associations were more significant in patients older than 60 years. Our findings revealed a nonlinear correlation between ambient temperature and the risk of oral diseases in Guangzhou. Lower temperatures have become significant risk factors for oral diseases and older patients.