A Time Series Study On The Effect Of Meteorological Factors On The Admission Of Cardiovascular Diseases To Residents In Hefei City

Objective:To understand the general situation and time change characteristics of cardiovascular disease admissions and temperature of Hefei residents in July 1,2015 to October 31,2017,to explore the relationship between meteorological factor（temperature,humidity,pressure）and cardiovascular disease admission by time series analysis method,and to explore the heat and cold effect of temperature and the attribution analysis of temperature cold and heat,to identify sensitive people,This study provides a basis for prevention of cardiovascular diseases,rational allocation of medical resources and reduction of hospitalization costs.Methods:1.The data of admission cases of cardiovascular diseases were collected from July 1,2015 to October 31,2017 in several third Class A Hospitals in Hefei.The case information included age,sex,home address,disease diagnosis and ICD-10 code for diagnosis of diseases.According to the tenth edition of international disease classification standard（ICD-10）,case data are summarized.Daily air pollutant concentration data of Hefei city from July 1,2015 to October 31,2017 come from Hefei Environmental Monitoring Center Station,including 24 h PM₁₀,PM_2.5,SO₂,NO₂,CO concentration data and 1 h O₃ concentration data.For the same period,meteorological data were downloaded from the China Meteorological Science data sharing Service platform（http://data.cma.gov.cn/,）,which includes daily mean temperature,daily average relative humidity and daily average pressure.2.To establish the time series of admission and temperature of cardiovascular disease,the general additive model（Generalized additive model,GAM）and the distributed lag nonlinear model（Distribution lag non-linear model,DLNM）were used to analyze the cardiovascular disease.In controlling the long-term trend of time and seasonality,the week effect,the holiday effect,the average pressure,the average relative humidity,The effects of air pollutants and other mixed factors were analyzed:（1）Quantitative analysis of the relationship between temperature and admission to hospital on cardiovascular disease day,and whether the effect of temperature has lag effect.（2）To define temperature as high and low temperature,to analyze the cold and heat effect of temperature on admission of cardiovascular disease.（3）To analyze the difference of temperature and admission of cardiovascular disease according to different subgroups,and to explore the sensitive population.（4）Attribution analysis of temperature.Results:1.There were 35096 admissions with cardiovascular disease in Hefei during the period from July 1,2015 to October 31,2017.The average was 42 cases per day,of which 19507 men were hospitalized.According to the age stratification,the number of admission to cardiovascular disease in the age group under 65 years old was significantly lower than that in the age group be equal or greater than 65 years old,and the daily mean values of SO₂,NO₂ and PM₁₀ were 12.40μg/m³,42.04μg/m³ and79.38μg/m³,respectively.The average temperature,humidity,barometric pressure were18.10℃,76.11%,1023.33hpa,respectively.2.During the study period,there was a nonlinear relationship between meteorological factors and admission to cardiovascular disease,and there was a lag relationship.In the generalized additive model analysis,the maximum lag effect of humidity for total population,male,female,under 65 years old andbe equal or greater than 65 years old group was 1.004（95%CI:1.002-1.006）,respectively.1.004（95%CI:1.002-1.006）,1.004（95%CI:1.002-1.007）,1.010（95%CI:1.007-1.013）and 1.001（95%CI:1.000-1.003）;For the total population,male,female,under 65 years old group,and be equal or greater than 65 years old group,the maximum lag effect was 1.006（95%CI:1.001-1.011）,1.005（95%CI:0.997-1.012）,1.008（95%CI:1.001-1.015）,1.013（95%CI:1.001-1.025）and 1.005（95%CI:0.999-1.011）,respectively; For the total population,male,female,under 65 years old group,and be equal or greater than 65 years old group,the maximum lag effect was 1.005（95%CI:1.001-1.008）,1.000（95%CI:0.996-1.004）,1.008（95%CI:1.000-1.013）,1.000（95%CI:0.990-1.001）,1.010（95%CI:1.005-1.014）,respectively,but there was no significant difference in female and under 65 years old group（P>0.05）.3.In the hysteresis nonlinear model analysis,we found that the maximum lag effect of humidity for total population,male,female,under 65 years old and be equal or greater than 65 age group was 1.075（95%CI:0.953-1.212）1.534（95%CI:0.226-3.002）,1.222（95%CI:1.022-1.462）,1.540（95%CI:0.142-4.166）and 1.045（95%CI:0.898-1.216）.For the total population,male,female,under 65 years old group,and be equal or greater than 65 years old group,the maximum lag effect was 1.005（95%CI:0.988-1.022）,1.010（95%CI:0.987-1.033）,1.004（95%CI:0.993-1.015）,1.047（95%CI:1.019-1.077）and 0.978（95%CI:0.962-0.996）,respectively.4.In the nonlinear analysis of distributed hysteresis,we analyzed the effect of cold and heat temperature on the cumulative lag of cardiovascular disease in hospital.For the effects of very low temperature,medium low temperature,very high temperature and medium high temperature,the relative risk rr values are 0.616（95%CI:0.423-0.891）,1.081（95%CI:1.019-1.147）,1.078（95%CI:0.752-1.547）,1.015（95%CI:0.988-1.043）,respectively,but no statistical significance of high temperature（P>0.05）.5.Sex and age had a significant effect on the relationship between temperature and hospitalization of cardiovascular disease.Women and be equal or greater than 65 years old were more sensitive to the effect of heat,and those of under 65 years old and men were more sensitive to the effect of cold.6.In attribution analysis,we found that moderate hypothermia and moderate hyperthermia had a higher impact on admission to cardiovascular disease than extreme cold and extreme high temperature.7.The results of generalized additive model and distributed delay nonlinear model show that the effect of distributed delay nonlinear model is larger.Conclusions:1.Temperature,humidity and air pressure in Hefei City from July 1,2015to October 31,2017 have an impact on cardiovascular disease admission,suggesting that meteorological factors may increase the risk of cardiovascular disease admission.2.Gender and age have an impact on the relationship between meteorological factors and admission to cardiovascular disease.Men and people under 65 years old are more sensitive to humidity;women and people under 65 years old are more sensitive to air pressure.3.Men and people under 65 years old are more sensitive to the cold effects of low temperatures;however,women and people be equal or greater than 65 years old are more sensitive to the heat effects of high temperatures.4.Extremely low and extremely high temperatures may increase the risk of morbidity,and medium to high and low to medium temperatures may cause a higher disease burden.