Rapid weather changes are associated with increased ischemic stroke risk: a case-crossover study

Abstract

Observational studies focusing on absolute meteorological values suggest an association between meteorological parameters and stroke risk but these results are inconsistent and conflicting. Since changes in weather can provoke atrial fibrillation, we examined the association between rapid weather changes and stroke risk in 1694 patients with determinable onset of stroke symptoms in a case-crossover study in central Germany. Days one to three before stroke onset were classified as hazard periods and day seven as the respective control period. Risk of ischemic stroke in relation to 24 h differences in mean ambient temperature, relative humidity and atmospheric pressure was determined. The association between temperature and stroke risk appears to be close to linear with an increase in stroke risk of 11 % (odds ratio 1.11, 95 % confidence interval 1.01-1.22) for each 2.9 °C temperature decrease over 24 h. In individuals with a higher cardiovascular risk, stroke risk increased by 30 % (1.30, 1.06-1.61). Risk for cardioembolic strokes increased by 26 % (1.26, 1.06-1.50). Rapid positive or negative changes in relative humidity (>5 %) and atmospheric pressure (>10 hPa) increased stroke risk by a maximum of 30 % (1.30, 1.02-1.66) and 63 % (1.63, 1.10-2.42). In individuals with a higher cardiovascular risk, rapid changes in atmospheric pressure were associated with a four-times higher stroke risk (4.56, 1.26-16.43). Our results suggest that rapid decreases in ambient temperature and rapid changes in relative humidity and atmospheric pressure increase stroke risk under temperate climate conditions. Individuals with a high cardiovascular risk profile seem to be at greater risk.

Ambient Temperature and Stroke Occurrence: A Systematic Review and Meta-Analysis

“…Sex and age differences are apparent in stroke incidence, severity and prognosis [ 44 , 45 ]. With regards to temperature, the effects of sex on the association between ambient temperature and IS risk are in line with previous reports [ 25 , 38 , 46 ], but there is absence of evidence of gender differences for ICH and SAH. A recent meta-analysis reported that the association between ambient temperature and stroke occurrence was irrelevant for those who were 18 to 64 years old, but it is stronger among the elderly (≥65 years).…”

Seasonal Variations in Neurological Severity and Outcomes of Ischemic Stroke ― 5-Year Single-Center Observational Study ―

“…In hospital-based studies with analysis based on subtypes, cardioembolic stroke was generally most common in winter, and other subtypes of stroke were common in warmer seasons. 15,35,36 However, one should be careful about discussing seasonal variation of stroke onset based on single-center studies, because there might be some differences in the prehospital comes (mRS), and a relatively high follow-up rate at 1 year, exceeding four-fifths. When the present patients were divided into cardioembolic and noncardioembolic stroke groups, the former showed a winter-excess frequency, and the latter showed an insignificant peak in summer.…”

“…Second, the season might be a rougher explanatory variable than other meteorological conditions such as temperature, atmospheric pressure, relative humidity, and newer social environments such as air pollution. 16,[18][19][20]36,42 Third, it was difficult to clarify the definite results of noncardioembolic stroke patients divided by 3 further subtypes because of the small patient numbers. Fourth, recent therapeutic strategies such as endovascular thrombectomy and direct oral anticoagulants were adopted rapidly during the 5-year study period.…”

Weather, Weather Changes and the Risk of Bell’s Palsy: A Multicenter Case-Crossover Study

“…This approach is an established and efficient variation of the case-control study design and examines the association between a brief and transient exposure and the risk for the onset of an acute and rare event [17]. For example, we and others have successfully applied the case-crossover study design to examine the relationships between atmospheric conditions and ischemic stroke [18], myocardial infarction [19], or epileptic seizures [20]. In contrast to the case-control approach, data in this casecrossover study are analyzed by intraindividual comparison of meteorological conditions shortly before the onset of BP with meteorological conditions that were present in the same patient's recent past.…”