Background: Although multiple combinations of weather factors may contribute to an increased incidence of Mycoplasma pneumoniae (M. pneumoniae) pneumonia, few studies have investigated the association between weather factors and cases of M. pneumoniae.
Methods: We acquired data for M. pneumoniae pneumonia cases and weather factors in Fukuoka, Japan, from 1999 to 2007 and used time-series analysis to assess the effects of weather variables on M. pneumoniae pneumonia cases, adjusting for confounding factors. A total of 13,056 M. pneumoniae pneumonia cases were reported during the nine-year study period, of which 12,234 (93.7%) were under 15 years of age.
Results: The weekly number of M. pneumoniae pneumonia cases increased by 16.9% (95% CI: 11.3-22.8) for every 1°C increase in the average temperature and by 4.1% (95% CI: 2.7-5.5) for every 1% increase in relative humidity.
Conclusions: From 1999 to 2007, M. pneumoniae pneumonia cases increased significantly with increased average temperature and relative humidity in Fukuoka, Japan.