Association between climate variables (cold and hot weathers, humidity, atmospheric pressures) with out-of-hospital cardiac arrests in Rasht, Iran

Abstract Climate change is one of the most important concerns for public health that affects communities and is a threat to human health. Few cross-sectional studies investigated the effects of extreme temperature as a risk factor on the cardiovascular system and the Out-of-Hospital Cardiac Arrests (OHCA).The current study aims to investigate the association between climate variables (cold and hot weathers, humidity, atmospheric pressures) with Out-of-Hospital Cardiac Arrests in Rasht, Iran.This is an ecological time-series study, which investigated 392 patients with OHCA that were hospitalized in Dr. Heshmat Medical center of Rasht city in a 3-years period. Data on meteorological variables were obtained from the General Meteorological Department of Guilan Province. Information regarding the number of cardiac arrest admissions was obtained from the sole specialized cardiac hospital of Rasht. Data were analyzed using R software.Hot weather decreases the number of cardiac attacks on the same day (lag 0), while the cold weather (relative risk (RR) = 1.408; confidence interval (CI): 1.014–1.955) increases the number of OHCA cases and unsuccessful cardiopulmonary resuscitation (CPRs). Low humidity (RR = 1.76; CI: 1.006–3.79) is associated with increased unsuccessful CPRs. High atmospheric pressures (RR = 1.166; CI: 1.001 to 1.787) are also associated with an increased number of cardiac arrest admissions. For women, men, and those aged >65 years of old, exposure with severe cold (RR = 1.335; CI: 1.014–1.758) and hot weathers, respectively, increases and decreases the number of cardiac arrest admissions.Cold weather has immediate impacts on the incidence of OHCA cases and unsuccessful CPRs. Decreasing humidity also increases the number of and decreases the success rate of CPRs. Increasing the awareness of patients with cardiovascular diseases (CVDs as well as improving the preparedness of emergency care teams can decrease the impacts of climate variables.