Relationship of Meteorological Variable and Cerebrovascular Events: An Ecological Time Series Study

Background: Climatic conditions contribute to changes in red blood cells, thrombocyte count, and blood pressure. In cold weather, blood viscosity increases, but increasing body temperature raises coagulation factors. Also, plasma fibrinogen concentrations are higher in older patients. All of these factors can contribute to the incidence of stroke. Objectives: Our purpose was to assess the relationships between metrological factors and the rate of stroke patients in the north of Iran. Materials & Methods: We used a time-series analysis to investigate the association between metrological factors and hospital admission of cerebrovascular events from ۲۰۱۴ to ۲۰۱۹ using distributed lag nonlinear models. Results: Hot temperature (≥۳۴°C) was significantly associated with an increased risk of stroke admission. In the general population, severe cold (≤۰°C) was significantly related to the risk of stroke on the third day after exposure (relative risk [RR]=۱.۰۱۷; ۹۵% confidence interval [CI], ۱.۰۰%-۱.۰۳۵%). Also, a low temperature of ۷°C on ۵-۶ lag days was significantly associated with the risk of stroke. The risk of stroke hospital admission was not significantly associated with low humidity. Humidity with a low percentage (۸%-۹%) two days after exposure was significantly related to the risk of intracerebral hemorrhage (RR=۵.۰۸۹; ۹۵% CI, ۱.۰۰۲%-۲۵.۸۳۵% ) (RR=۴.۸۴۱; ۹۵% CI, ۱.۰۱۴%-۲۳.۱۰۹%), respectively. Conclusion: The results show that hot and cold temperatures are associated with stroke admission, and low humidity increases the risk of intracranial hemorrhage. This study suggests that changes in meteorological variables can raise the risk of stroke and exacerbate the pathogenicity in vulnerable people to these diseases.

Keywords:

Climate change , Stroke , Cerebrovascular disorders