Effects of ambient temperature and air pollutants on bacillary dysentery from 2014 to 2017 in Lanzhou, China

Abstract

Background: Previous studies have always focused on the impact of various meteorological factors on bacillary dysentery (BD). However, only few studies have investigated the effects of climate and air pollutants on BD incidence simultaneously. This study aimed to investigate the effects of temperature and air pollutants on BD in Lanzhou. Methods: Daily data of BD cases and environmental factors from 2014 to 2017 were collected. A generalized additive model (GAM) was conducted to explore the relationship between environmental factors and BD. Then a distributed lag non-linear model (DLNM) was developed to assess the lag and cumulative effect. Furthermore, this study explored the variability across gender and age groups. Results: A total of 7102 cases of BD were notified over the study period. High temperature can significantly increase the risk of BD during the whole lag period, temperature has different exposure effects on different genders and age groups. With 9℃ as the reference value, each 1℃ rise in temperature result in a 4.8% (RR=1.048, 95%CI: 0.996, 1.103) increase in the number of cases BD at lag 0 day. With 50μg/m3 as the reference value, each 5μg/m3 rise in PM2.5 caused a 11.3% (RR=1.113, 95%CI: 1.066, 1.162) increase in the number of BD cases at lag 0. Low concentration of PM10 in the lag of 10-14 days can significantly increase the risk of BD, while high concentration PM10 in the lag of 6-14 days can significantly increase the risk of BD. Conclusions:Temperature, PM2.5 and PM10 are closely related to the incidence of bacillary dysentery. Our findings suggest adaptation plans that target vulnerable populations in susceptible communities should be developed to reduce health risks.