Effects Of Short-term Single And Combined Exposure To Air Pollutants On Cardiovascular Health Indicators In Schizophrenics

BackgroundSchizophrenia,as a severe mental illness,has a high prevalence and a large disease burden.Life expectancy is 20%lower in patients with schizophrenia than in the general population,and most of this increased mortality is a result of complications such as cardio cerebrovascular disease,diabetes,and cancer complicating the condition.Patients with schizophrenia have more than three times the risk of comorbid cardiovascular disease and the resulting mortality than normal individuals.Abnormal alterations of various metabolic disorders,especially cardiovascular health-related indicators（blood pressure dyslipidemia and other abnormalities）in schizophrenic patients increase the risk of developing cardiovascular disease and reduce their life span by 10-25 years.Environmental factors especially short-term exposure to air pollution may induce abnormalities in cardiovascular health indicators,but there is no related study in schizophrenia.In addition,relevant studies on the joint effects of air pollution combined exposure on cardiovascular health indicators are not enough.Therefore,we conducted the present study to:（1）To determine the effects of single pollutant short-term exposure on cardiovascular indicators in schizophrenics;（2）To identify the relative importance of individual air pollutants on cardiovascular health indicators and to analyze the joint effects of air pollutants combined exposure on cardiovascular health indicators of schizophrenia.MethodsBased on the schizophrenia cohort established from September 2018 to January2020,we recruited 248 schizophrenia patients from Anhui provincial mental health center for this cross-sectional study.We collected sociodemographic and clinical information of these schizophrenia patients,measured blood pressure the day after admission,and examined serum biochemical parameters,including fasting blood glucose（FBG）,total cholesterol（TC）,triglycerides（TG）,and high-density lipoprotein cholesterol（HDL-C）.Meteorological data and air pollutants data were collected for the study period,including PM_2.5.PM₁₀,nitrogen dioxide（NO₂）,sulfur dioxide（SO₂）,ozone（O₃）,carbon monoxide（CO）,relative humidity,mean temperature.The inverse distance weighted method（IDW）was used to assess the mean air pollutants exposure levels of the study population on individuals 7 days prior to admission.Multiple linear regression was used to analyze the association between short-term exposure to single air pollutants and cardiovascular health indicators in patients with schizophrenia.Bayesian nuclear machine regression（BKMR）models were used to identify the relative importance of each air pollutant on cardiovascular health indicators and the joint effect of air pollutants combined exposure on cardiovascular health indicators.ResultsMultiple linear regression analysis found that PM_2.5 each IQR increase（29.16μg/m~3）was significantly associated with a 6.16%increase in FBG（95%confidence intervals（CIs）:2.61%,9.70%）,11.13%increase in TG（95%CIs:0.77%,21.49%）,and2.15 mm Hg increase in DBP（95%CIs:0.39,5.75）.Each IQR increase in NO₂（24.43μg/m~3）was associated with a 7.99%（95%CIs:3.98%,11.99%）increase in FBG,18.28%（95%CIs:6.59%,29.98%）increase in TG,and 6.39%（95%CIs:-12.02%,-0.77%）decrease in HDL.Each IQR increase in O₃（60.63μg/m~3）was positively associated with TG levels（Percentage change:18.28%;95%CIs:7.71%,28.47%）and negatively associated with HDL-C（Percentage change:6.97%;95%CIs:-11.97%,-1.98%）,while no significant differences were observed for other pollutants.The results related to posterior inclusion probability（PIP）of BKMR showed that PM_2.5（PIP=0.918）and NO₂（PIP=0.999）were the key pollutants affecting FBG.PM_2.5（PIP=0.986）,NO₂（PIP=0.963）and O₃（PIP=0.991）had high relative importance on TG,NO₂（PIP=0.941）and O₃（PIP=0.681）were the key pollutants affecting HDL–C.Air pollutant mixture exposures produced joint effects on FBG,TG,HDL–C,and DBP in schizophrenics.Controlling for other pollutants at the median,PM_2.5 and NO₂ had significant effects on FBG,PM_2.5,NO₂ and O₃ on TG and NO₂ and O₃ on HDL–C.A possible interaction between PM_2.5 and NO₂ was found in the analysis of FBG and TG.ConclusionsWe found the single and combined effects of PM_2.5 for FBG and DBP,PM_2.5 NO₂and O3 on TG,O₃ and NO₂ on HDL-C in schizophrenics.BKMR was used for the first time to analyze the joint effects of air pollution mixture on cardiovascular health indicators in schizophrenics.Our results suggest the potential public health risks of exposure to multiple air pollutants and support strategies that continue to reduce the concentration of ambient air pollutants can improve the cardiovascular health of patients with schizophrenia.Future intervention studies across multiple regions are needed to clarify the associations between air pollutants and cardiovascular health indicators in patients with schizophrenia.