Supplementary file 1_Unraveling complex interactions of meteorological factors and sulfur dioxide on other infectious diarrhea: evidence from a subtropical city.docx

BackgroundThe incidence of other infectious diarrhea (OID) is rising, imposing a significant medical burden. While meteorological factors affect OID, few studies have examined sulfur dioxide (SO2) or its interactions with these variables.
MethodsUsing quasi-Poisson and distributed lag non-linear models, we analyzed the lagged, non-linear effects of meteorological factors and SO2 on OID cases in Fuzhou, China (2015–2019). Interactive effects between SO2 and meteorological variables were evaluated using multiplicative terms, multiplicative scale, relative excess risk due to interaction (RERI), and attributable proportion (AP). Stratified analyses highlighted vulnerable groups.
ResultsThe relationship between OID and mean temperature (MT), mean relative humidity (MRH) and SO2 were represented by U-, L-, and J-shaped curves, respectively. A synergistic effect was found between MT and MRH, where low levels of both increased OID risk, while SO2 and MT showed an antagonistic effect, with high SO2 and low MT raising OID risk. Children aged 3–4 years were particularly sensitive to extremely low MT.
ConclusionThese results underscore the importance roles of MT, MRH, and SO2 in OID risk, and highlight the need for prediction and prevention strategies targeting the co-exposure of environmental factors.