Association Of Air Pollution And Meteorological Factors With Admission Risk For Gout

ObjectivePrevious studies have shown that air pollution and meteorological factors are significant environmental factors in the progression of gout.At present,there are epidemiological and mechanistic studies at home and abroad to explore the correlation between air pollution,meteorological factors and gout.But the results are inconsistent and lack systematic evidence.On the basis of previous studies,this study intended to use time-series analysis to investigate the short-term effects of air pollution and meteorological factors on the admission risk of gout in Hefei,Bengbu and Anqing,Anhui Province,and to evaluate potential modification factors,identify gout susceptible populations and determine seasonal differences,in order to provide scientific basis for the prevention and management of gout.MethodsAdmission data of gout patients were collected from a number of Grade A comprehensive hospitals in Hefei,Bengbu and Anqing,Anhui Province,and the correlation between four kinds of air pollutants(NO₂,CO,O₃ and PM_2.5)and three meteorological factors（mean temperature（MT）,diurnal temperature range（DTR）and RH（relative humidity））and the admissions risk of gout was analyzed.The air pollution data came from China Environmental Monitoring Station and included six kinds of air pollutants:PM₁₀,PM_2.5,SO₂,NO₂,O₃ and CO.The data of meteorological factors were from China Meteorological Data Service Center and included MT,RH,daily maximum temperature and daily minimum temperature.After establishing the time series of gout hospitalizations over time,the generalized linear model（GLM）combined with a distributed lag nonlinear model（DLNM）was used to evaluate the short-term effects of air pollutants and meteorological factors on admission risk for gout.When analyzing one air pollutant/meteorological factor,the influence of confounding factors such as other air pollution/meteorological factors（covariates）,long-term trends,holiday and day of the week effects were controlled.Sensitivity analysis was used to evaluate the stability of the models.In addition,to explore potential modifiers,identify people susceptible to gout,and determine seasonal differences,the gout database was stratified by sex（male vs.female）,age（≥65 years old vs.<65 years old）,and season（cold season vs.warm season）.Air pollutants were analyzed by gender,age and season,and meteorological factors were analyzed by gender and age.Finally,meta-analysis was used to summarize the analysis results of the association between air pollutants and meteorological factors and the admission risk of gout patients in Hefei,Bengbu and Anqing.ResultsFrom January 1,2018 to December 31,2021,a total of 10615 patients with gout were observed in Hefei,Anhui Province.Among them,7914 patients（74.55%）were males,the sex ratio was 2.93:1,and 1877 patients（17.68%）were≥65 years old.There were more gout admissions in the warm season than in the cold season（5980 vs.4635）.From January 1,2015 to December 31,2020,a total of 1859 patients with gout were observed in Bengbu,Anhui Province.Among them,1667 patients（89.67%）were males,the sex ratio was 8.68:1,and 948 patients（51.00%）were≥65 years old.There were more gout admissions in the warm season than in the cold season（963 vs.896）.From January 1,2016 to December 31,2020,a total of 8675 patients with gout were observed in Anqing,Anhui Province.Among them,7873 patients（90.76%）were males,the sex ratio was 9.82:1,and 3207 patients（36.97%）were≥65 years old.There were more gout admissions in the warm season than in the cold season（5140 vs.3535）.The analysis results of the association between NO₂ and gout admission risk in Hefei and Anqing showed that the risk of hospital admission for gout increased with every increase in NO₂ concentration of 10μg/m³（reference value P50）.The meta-analysis results of NO₂ in Hefei,Bengbu and Anqing showed that high NO₂ exposure was a risk environmental factor for admission risk of gout,with the maximum RR value at 0-7 days lag（RR:1.051,95%CI:1.019-1.083）.The analysis results of CO in Bengbu and Anqing showed that the risk of hospitalization for gout increased with every 1 mg/m³ increase of CO concentration（reference value P50）,and the strongest effect RR value was at the 14th day lag of Bengbu results（RR:1.152,95%CI:1.025-1.295）.However,the meta-analysis results of CO showed no association between CO and daily hospital admission risk for gout.The analysis results of O₃ in Hefei and Anqing showed that the risk of hospitalization for gout decreased with an increase in O₃ concentration of 10μg/m³（reference value P50）.The meta-analysis results of O₃showed that high O₃ exposure was a protective factor for hospitalization risk of gout.The analysis results of PM_2.5 in Anqing showed that for every increase in PM_2.5concentration of 10μg/m³（reference value P50）,the risk of hospitalization for gout increased by 3.3%（RR:1.033,95%CI:1.003-1.063,lag 0-7 days）.However,the meta-analysis results of PM_2.5 showed no association between PM_2.5 and daily admission risk for gout（P>0.05）.The analysis results of the association between MT and gout admission risk in Hefei and Anqing showed that high MT（P90）exposure（reference P50）increased the risk of hospital admission for gout.The meta-analysis results of MT in Bengbu,Hefei and Anqing showed that high MT was associated with an increased daily admission risk for gout,and the risk-effect RR was greatest at a lag of 0-16 days（RR:1.602,95%CI:1.316-1.949）.The analysis results of DTR in Hefei,Bengbu and Anqing all showed that high DTR（P75）exposure（reference value P50）increased the risk of hospital admission for gout.The meta-analysis results of DTR showed that high DTR was associated with an increased daily admission risk for gout,and the risk-effect RR was greatest at a lag of 0-21 days（RR:1.297,95%CI:1.133-1.484）.The analysis results of RH in Hefei,Bengbu and Anqing showed that high RH（P90）exposure（reference value P50）increased the risk of hospital admission for gout.The meta-analysis results of RH showed that high RH was associated with an increased daily admission risk for gout,and the lag effect was strongest at 0-16 days lag（RR:1.278,95%CI:1.132-1.442）.The results of meta-analysis in Hefei,Bengbu and Anqing subgroups showed that the aged were more sensitive to high NO₂ exposure and men were more sensitive to high PM_2.5 exposure,while the risk of gout hospitalization was greater when exposed to high CO in cold season.The results of meta-analysis showed that exposure to high concentration of O₃ had a stronger protective effect on males.The meta-analysis results of DTR showed that exposure to high DTR increased the risk of hospitalization for gout in men.However,the meta-analysis results of MT and RH showed that there was no statistically significant difference in the risk effect RR value and 95%confidence interval of high MT and high RH exposure in gender and age subgroups（P>0.05）.ConclusionsThis study found that air pollution and meteorological factors had short-term lag and cumulative effects on the number of hospital admissions for gout.Among them,exposure to high concentration of NO₂,CO,and PM_2.5 was associated with an increased risk of hospitalization for gout,and high MT,DTR,and RH exposure showed the same effect,while high O₃ exposure was associated with a reduced risk of gout hospital admission.The results of the age and sex subgroup analysis showed that males were more sensitive to high PM_2.5 and high DTR exposure,and the elderly were at greater risk of gout admission when exposed to high NO₂ concentration.In addition,the results of a seasonally stratified analysis showed that exposure to high concentration of CO in the cold season was associated with a greater risk of hospitalization for gout.Gout patients should reduce or avoid exposure to air pollution and adverse meteorological factors,especially in vulnerable people with gout and during the susceptible season.