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The topic of inflammatory bowel disease (IBD) has attracted more and more attention. Accumulating evidence suggests that exposure to air pollutants is associated with IBD, yet the results are inconsistent and study about daily exposure is few. This study evaluated the association between daily air pollution and IBD in Hefei, China. Daily IBD admission data were obtained from two hospitals in Hefei from January 1, 2019, to December 31, 2019. Daily concentrations of major air pollutants were provided by the Hefei Environmental Protection Bureau. Meteorological data were collected from China Meteorological Data Network. Distributed lag nonlinear model (DLNM) considering both the lag effects of exposure factors and nonlinear relationship of exposure-reaction was used to assess the effect of daily air pollutants exposure on IBD admission. During the study period, totally 886 cases of IBD were recruited, including 313 cases of ulcerative colitis (UC) and 573 cases of Crohn's disease (CD). The findings showed PM2.5, O3, and CO exposure significantly increased the risk of IBD. Mean concentrations of PM2.5, O3, and CO in Hefei were 43.85ug/m3, 100.78ug/m3, and 0.76 mg/m3, respectively. Each increase of 10 mg/m3 in PM2.5/O3 and 0.1 mg/m3 in CO increased the risk of IBD. The strongest effects of these three pollutants on IBD were observed in lag2-lag3 (RR = 1.037, 95% CI: 1.005–1.070%), lag3 (RR = 1.020, 95% CI: 1.002–1.038%), and lag2 (RR = 1.036, 95% CI: 1.003–1.071%), respectively. In warm seasons, PM2.5, O3, and CO had a stronger effect increased the risk of IBD, which were observed in lag2 (RR = 1.104, 95% CI: 1.032–1.181%), lag2 and lag5 (RR = 1.023, 95% CI: 1.002–1.044%; RR = 1.036, 95% CI: 1.004–1.069%), and lag2 (RR = 1.071, 95% CI: 1.012–1.133%), respectively. Air pollutant (PM2.5, O3, and CO) exposure could increase the risk of IBD, while the most susceptibility seasons for the exposure were mainly in warm seasons. The results of this study suggest that air pollutants increase the risk of IBD patients in Hefei, China, providing a basis for developing countries to improve effective prevention of IBD, and a potential opportunity to avoid part of the risk of the onset or recurrence of IBD. This study contributes to the knowledge of the association between air pollution and IBD, but the associations need to be verified by further studies. [ABSTRACT FROM AUTHOR]

Under current global climate conditions, there are insufficient studies on the health influences of cold spells, especially on mental health. This study aimed to examine the effect of cold spells on schizophrenia admissions and to analyze the potential interaction effect with the air quality index (AQI). Daily data on schizophrenia admissions and climatic variables in Hefei were collected from 2013 to 2019. Based on 20 definitions, the impacts of cold spells were quantified separately to find the most appropriate definition for the region, and meta-regression was used to explore the different effect sizes of the different days in a cold spell event. In addition, the potential interaction effect was tested by introducing a categorical variable, CSH, reflecting the cold spell and AQI level. The cold spell defined by temperature below the 6th centile while lasting for at least three days produced the optimum model fit performance. In general, the risk of schizophrenia admissions increased on cold spell days. The largest single-day effect occurred on the 12th day with RR = 1.081 (95% CI: 1.044, 1.118). In a single cold spell event, the effect of the 3rd and subsequent days of a cold spell (RR = 1.082, 95% CI: 1.036, 1.130) was higher than that on the 2nd day (RR = 1.054, 95% CI: 1.024, 1.085). Similarly, the effect of the 2nd day was also higher than that of the 1st day (RR = 1.027, 95% CI: 1.012, 1.042). We found a synergistic effect between cold spells and high AQI in the male group, and the relative excess risk due to interaction (RERI) was 0.018 (95% CI: 0.005–0.030). This study suggested that the impacts of cold spells should be considered based on the definition of the most appropriate for the region when formulating targeted measures of schizophrenia. The discovery of the synergistic effect was referred to help the selection of the timing of precautions for susceptible people. • Cold spells were found to be associated with schizophrenia admissions. • The mean temperature below the 6th centile while lasting for at least three days produced the optimum model fit performance. • A high AQI may have a synergistic effect with cold spells on schizophrenia admissions in males. [ABSTRACT FROM AUTHOR]