Objective To examine the influence of floods on the incidence of other infectious diarrhea and to identify vulnerable populations in Chengdu city.

Methods We collected data on incidence of other infectious diarrhea, floods, and meteorology for Chengdu city from 2008 to 2012 and rearranged the data in time sequence. Then we analyzed the data to quantitatively assess the lag effect of floods on the incidence of other infectious diarrhea using distributed lag nonlinear model (DLNM) and we performed the analysis for people groups of different gender and age to identify populations vulnerable to floods-related incidence of the disease.

Results There were 7 floods events in Chengdu city during the 5-year period. Floods events increased the risk of other infectious diarrhea incidence for lag days 20 till lag days 40 among the residents in Chengdu city, with the other infectious diarrhea incidence risk ratio RR of 1.09 (95% confidence interval 95% CI: 1.01 – 1.17) at lag day 20, 1.11 (95% CI: 1.02 – 1.20) at lag day 30, and 1.12 (95% CI: 1.04 – 1.21) at lag day 40, respectively. The people more susceptible to floods-related incidence of other infectious diarrhea were 0 – 4 year old boys and girls with the RR of 1.10 (95% CI: 1.00 – 1.20) at lag day 40 and the RR of 1.14 (95% CI: 1.02 – 1.28) at lag day 50, 5 – 14 year old girls with the RR of 1.64 (95% CI: 1.22 – 2.20) at lag day 30, and≥65 years old women with the RR of 1.35 (95% CI: 1.02 – 1.77) at lag day 20.

Conclusion Floods, with a lagged effect, can increase the risk of other infectious diarrhea incidence among residents in Chengdu city. The results suggest that relevant measures should be implemented after floods events for the prevention of other infectious diarrhea incidence, especially among vulnerable populations.