Abstract
Background Intussusception is a primary cause of acute abdomen in young children, often requiring surgical intervention. However, its etiology is largely unknown. This study aimed to analyze trends and seasonality of intussusception procedures in Japan using a national database and to investigate their association with weather conditions and pediatric infectious diseases. Methods This retrospective study utilized the National Database of Health Insurance Claims and Specific Health Checkups of Japan (NDB) to analyze data on intussusception reduction procedures from fiscal years 2014 to 2022. Monthly meteorological data and pediatric infectious disease reports were collected for the same period. Statistical analyses, including the Wilcoxon signed-rank test, Pearson correlation, and partial least squares (PLS) regression, were performed on data from 2020 to 2022. Results The annual number of intussusception reduction procedures decreased from 5,564 in 2014 to 2,342 in 2022, with a sharp decline to 2,056 cases in 2020. A significant seasonal variation was observed, with a higher incidence in summer compared to spring (p=0.0134) and winter (p=0.0243). Significant positive associations were found between the number of intussusception reduction procedures and temperature (r = 0.5102, p = 0.0015; PLS coefficient = 0.3663; variable importance in projection (VIP) = 1.2466), relative humidity (r = 0.5479, p = 0.0005; PLS coefficient = 0.2479; VIP = 1.273), and pharyngoconjunctival fever (r = 0.5723, p = 0.0003; PLS coefficient = 0.5273; VIP = 1.6386). Conclusions This study revealed a declining trend in intussusception reduction procedures in Japan, with a notable decrease in 2020 potentially linked to the COVID-19 pandemic. The incidence peaked in the summer, showing strong associations with higher temperature, relative humidity, and pharyngoconjunctival fever outbreaks. These findings can contribute to developing more effective prevention and early diagnosis strategies for intussusception.