Impact of the environment changes on the occurrence of appendicitis: A retrospective study

Background Appendicitis is one of the most frequent infectious abdominal diseases worldwide. Recent studies suggest that high temperatures increase the risk of appendicitis, while its incidence decreases in high-income countries. Temperature may not be the only environmental parameter associated with appendicitis. The objective was to assess the impact of meteorological parameters on the occurrence of appendicitis in France between 2013 and 2022. Methods This is a retrospective observational study was based on data from the French national hospital discharge database and publicly available historical meteorological and environmental parameters data. The impact of age, temperature, humidity, altitude, wind force, atmospheric pressure and COVID-19 lockdown on the incidence of appendicitis was examined through a subgroup analysis stratified by age. Results Between 2013 and 2022, 761,414 patients underwent an appendectomy in France. While the risk of occurrence of appendicitis increased by 6.9% for each 10 ̊C increase of temperature. Among the other environmental parameters studied, a higher altitude was always associated with an increased risk of appendicitis while the impact of rising atmospheric pressure varied according to age classes. Finally, both humidity and wind force were significantly associated with appendicitis occurrence. This association was no longer significant during the COVID-19 lockdown. More generally, the COVID-19 lockdown period was associated with a reduced occurrence of appendicitis. Conclusion The risk of appendicitis was strongly associated with environmental parameters. The lockdown reduced the incidence of appendicitis, advocating for the implication of exogenic parameters in the pathophysiology of appendicitis.