ABSTRACT
Objective To explore the effect of air temperature on the hospitalization of rural residents with cardiovascular diseases and its lag effect in Dingxi city. Methods The meteorological data and air pollution data of Dingxi city from 2018 to 2019,as well as the daily hospitalization data of rural residents due to cardiovascular diseases,were collected.The distributed lag non-linear models were employed to analyze the relationship between daily mean air temperature and the number of inpatients with cardiovascular diseases.Meanwhile,stratified analysis was carried out according to gender,age,and disease. Results There was a non-linear relationship between air temperature and the number of hospitalized rural residents with cardiovascular diseases in Dingxi city.The exposure-response curve approximated a bell shape.The curves for different cardiovascular diseases appeared similar shapes,with different temperature thresholds.Low temperature(-7 ℃) and moderately low temperature(0 ℃) exhibited a cumulative lag effect on the number of patients hospitalized with cardiovascular diseases.With a cumulative lag of 7 days at -7 ℃ and 14 days at 0 ℃,the RR values peaked,which were 1.121(95% CI=1.002-1.255) and 1.198(95% CI=1.123-1.278),respectively.With a cumulative lag of 14 days at 0 ℃,the RR values were 1.034(95% CI=1.003-1.077) and 1.039(95% CI=1.004-1.066) for the number of hospitalized patients with ischemic heart disease and heart rhythm disorders,respectively.The cumulative lag effects of moderately high temperature(17 ℃) and high temperature(21 ℃) on ischemic heart disease,heart rhythm disorders,and cerebrovascular disease all peaked on that day.Specifically,the RR values at 17 ℃ and 21 ℃ were 1.148(95% CI=1.092-1.206) and 1.176(95% CI=1.096-1.261) for ischemic heart disease,1.071(95% CI=1.001-1.147) and 1.112(95% CI=1.011-1.223) for heart rhythm disorders,and 1.084(95% CI=1.025-1.145) and 1.094(95% CI=1.013-1.182) for cerebrovascular disease,respectively.There was no cumulative lag effect of air temperature on the number of hospitalized patients with heart failure.In addition,stratified analysis showed that low temperature(-7 ℃) and moderately low temperature(0 ℃) affected the number of hospitalized female patients with cardiovascular diseases,and only moderately low temperature(0 ℃) affected males.The cumulative lag effect of high temperature on females was higher than that on males.Air temperature exhibited a stronger impact on female patients than on male patients. Additionally,the population aged<65 years old was more sensitive to low temperature and high temperature than that aged ≥65 years old. Conclusions Air temperature changes increase the hospitalization risk of rural residents with cardiovascular diseases in Dingxi city,which presents a lag effect.The effects of air temperature on patients hospitalized due to cardiovascular diseases varied among different etiologies,genders,and ages.It is necessary to emphasize on the impact of temperature changes on health in residents,especially for key populations such as females,people aged<65 years old,and those with ischemic heart disease.