Effect of Meteorological Factors and Air Pollutants on Daily Hospital Admissions for Ischemic Heart Disease in Lanzhou, China

<b><i>Introduction:</i></b> Meteorological factors and air pollutants are believed to be associated with cardiovascular disease. Ischemic heart disease (IHD) is a major public health issue worldwide. Few studies have investigated the associations among meteorological factors, air pollutants, and IHD daily hospital admissions in Lanzhou, China. <b><i>Methods:</i></b> We conducted a distributed lag nonlinear model on the basis of 5-year data, aiming at disentangling the impact of meteorological factors and air pollutants on IHD hospital admissions. All IHD daily hospital admissions recorded from January 1, 2015, and December 31, 2019, were obtained from three hospitals in Lanzhou, China. Daily air pollutant concentrations and meteorological data were synchronously collected from Gansu Meteorological Administration and Lanzhou Environmental Protection Administration. Stratified analyses were performed by sex and two age groups. <b><i>Results:</i></b> A total of 23,555 IHD hospital admissions were recorded, of which 10,477 admissions were for coronary artery disease (CAD) and 13,078 admissions were for acute coronary syndrome. Our results showed that there was a nonlinear (J-shaped) relationship between temperature and IHD hospital admissions. The number of IHD hospital admissions was positively correlated with NO₂, O₃, humidity, and pressure, indicating an increased risk of hospital admissions for IHD under NO₂, O₃, humidity, and pressure exposure. Meanwhile, both extremely low (−12°C) and high (30°C) temperatures reduced IHD hospital admissions, but the harmful effect increased with the lag time in Lanzhou, China, while the cold effect was more pronounced and long-lasting than the heat effect. Subgroup analysis demonstrated that the risk on CAD hospital admissions increased significantly in females and &lt;65 years of age at −12°C. <b><i>Conclusion:</i></b> Our findings added to the growing evidence regarding the potential impact of meteorological factors and air pollutants on policymaking from the perspective of hospital management efficiency.