Meteorological Factors and Seasonal Stroke Rates: A Four-year Comprehensive Study

Abstract

Introduction: There is a growing body of evidence suggesting that acute cardiovascular events including stroke are not distributed randomly over time but instead depend on months/season of the year. We report the impact of meteorological variables in extremely hot and arid climate on stroke.

Methods: Acute stroke patients admitted from January 2014 to December 2017 were included. The data included demographics, clinical risk factors, temperature, solar radiation, relative humidity, dew point, wind speed, and atmospheric pressure. We calculated stroke rates/100,000/month.

Results: There were 3654 cases of stroke (ischemic stroke [IS]: 2956 [80.9%]; and intracerebral hemorrhage [ICH]: 698 [19.1%]) with no difference in hematocrit, creatinine, and blood urea between hot and cold seasons (p > .05). We observed a positive significant correlation of IS with the mean temperature (AOR: 1.023; 95% CI: 1.009-1.036; P = .001) and mean solar radiation (AOR: 1.268; 95% CI: 1.021-1.575; P = .032) showing a 2.3% and 26.8% higher risk relative to ICH respectively, a negative correlation between IS with relative humidity (AOR: 0.99; 95% CI: 0.984-0.997; P = .002), and atmospheric pressure (AOR: 0.977; 95% CI: 0.966-0.989; P < .001) was observed, 1% increase in the relative humidity correlate with 2.4% and 1% lower risk of IS incidence relative to ICH respectively.

Conclusion: We demonstrated a distinct seasonal pattern in the incidence of stroke with an increase in IS rates relative to ICH during the summer months with higher solar radiations that cannot be explained by physiological measures suggestive of dehydration or hem-concentration.

Keywords: ICH; Ischemic stroke; meteorological data; season.