Association Between Short-term Exposure To Air Pollution And The Risk Of Mumps In Hefei City:A Time Series Study

PurposeAs a crucial menace to human health and happiness,air pollution contributes to the global burden of disease.Previous studies have already illuminated the harmful effect of air pollution on respiratory,cardiovascular and nervous disease.Nevertheless,the association between exposure to air pollution and the risk of mumps was also currently unclear.Hence,this study adopted time-series analysis to quantify the impact of ambient air pollution on mumps in Hefei,Anhui Province.MethodsOur time-series analysis was conducted using data collected in Hefei from Dec1,2013 to Dec 31,2018.Daily counts of mumps cases were exported from infectious disease surveillance and registration system of Hefei Center for Disease Control and Prevention.Data on air pollutant concentrations were obtained from the urban air quality online monitoring and analysis platform established by the Ministry of Ecological and Environmental Protection,the indicators involving PM_2.5,PM₁₀,SO₂,NO₂,CO and O₃＿8h.Meteorological information over the study period containing average wind velocity（m/s）,relative humidity（%）and mean temperature（℃）.The GAM and DLNM model were applied to adjust these above meteorological variables,under this circumstances,exploring the impact of each pollutant on mumps and the possible lag days.Afterwards,the analysis was stratified by age,sex and season.In this study,single-pollutant model was used to analyze the main association between various pollutant indicators and the incidence of mumps,and two-pollutant and multi-pollutant models were adopted to verify the stability of the associations.ResultsFrom December 1,2013 to December 31,2018,the annual incidence of mumps in Hefei remained fluctuating between 10.71 to 16.50 per one hundred thousand persons during the study period,with a total of 5370 mump cases reported.The number of male cases was about 1.71 times than that of female cases.The 5-9 years were the dominate crowd and accounted for 34.56%of all number of annual reports cases,followed by1258 cases in the 10-14 years group and 1192 cases in the 0-4 years group,accounting for 23.43%and 22.20%,respectively.744 cases occurred in the 15-29 age group,accounting for 13.85%of the total cases.The slightest crowd of mumps were≥30 years group and accounted for 5.96%.Mumps occurred all the year round in Hefei,with a small epidemic peak in summer and winter.Over the study period,the mean concentration of each pollutant was 62.36μg/m³,88.08μg/m³,13.63μg/m³,38.05μg/m³,0.96mg/m³ and 53.25μg/m³ for PM_2.5,PM₁₀,SO₂,NO₂,CO and O₃,respectively.The single-day model showed that ambient PM_2.5,PM₁₀,SO₂,CO exposures were associated with mumps.For per IQR increase in each of the above pollutant concentrations（Lag 0）,the estimated effects were 1.031（95%CI:1.005-1.058）,1.030（95%CI:1.001-1.061）,1.085（95%CI:1.003-1.174）and 1.051（95%CI:1.008-1.095）,respectively.The cumulative effects of above pollutants reached maximum at different lag days,with the RRs with 95%CIs were 1.226（95%CI:1.021-1.472）for PM_2.5（Lag0-12）,1.340（95%CI:1.076-1.669）for PM₁₀（Lag 0-14）,1.272（95%CI:1.009-1.603）for SO₂（Lag 0-4）,and 1.147（95%CI:1.016-1.295）for CO（Lag 0-4）,respectively.On the contrary,it is found that each IQR increase in NO₂ was associated with decreased risk of mumps at 0-1 lag days（RR=0.916,95%CI:0.846-0.991）.In this study,O₃ were not statistically significantly associated with the incidence of mumps in the single or multi-lag models.Subgroup analysis showed that male was more sensitive to the increase of SO₂ and CO concentration,while the acute effects of PM_2.5 and PM₁₀ were more pronounced in women.Furthermore,we found that people aged 5-9,10-14 and15-29 years were most susceptible to elevated levels of air pollutants,although no association was found among young children aged 0-4 years;compared to warm season,elevated concentrations of ambient pollutants had significantly increased the risk of mumps during the cold season,especially SO₂ and CO.Moreover,after adjusting for other co-pollutants,the estimate effects of PM_2.5,NO₂ and CO maintained stable in the two-pollutant and multi-pollutant models,expect for O₃,the effects of other pollutants on the incidence of mumps were all statistically significant.ConclusionIn this research,the results indicated that exposure to ambient air pollution may related to the increased risk of mumps,with lagged and cumulative effects.This study supplemented to a gap in previous research in this area and provided new evidence on the characteristics of different lag patterns,susceptible populations,and total exposure-response curves,which may contribute to understand the environmental drivers of mumps transmission.Environmental protection departments shall strengthen the real-time monitoring of various pollutant indicators and formulate reasonable concentration limits for each pollutant,so as to reduce the impact of ambient air pollution on public health.