Marian Christoph Neidert1, Michael Sprenger2, Marius Mader3, Giuseppe Esposito3, Jonas Aurel Hosp4, Oliver Bozinov3, Luca Regli3, Jan-Karl Burkhardt3. 1. Department of Neurosurgery, University of Zurich, Zurich, Switzerland. Electronic address: marian.neidert@usz.ch. 2. Institute for Atmospheric and Climate Science, ETH Zurich, Zurich, Switzerland. 3. Department of Neurosurgery, University of Zurich, Zurich, Switzerland. 4. Department of Neurosurgery, University of Zurich, Zurich, Switzerland; Vascular Neurology and Neurorehabilitation, Department of Neurology, University of Zurich, Zurich, Switzerland.
Abstract
OBJECTIVE: To investigate the influence of meteorological factors on the incidence of intracerebral hemorrhage (ICH). METHODS: We included 295 ICH admissions between 2005 and 2013. The hourly meteorological parameters considered were surface pressure, temperature, relative humidity, wind gusts, and precipitation. To minimize confounding effects of seasonality, data were analyzed with the following 3 complementary statistical approaches: 1) deviation of daily measure from the 10-year monthly mean at the day of ictus; 2) deviation from monthly average with respect to changes in daily measures between the day of ictus and 2 days before; and 3) evolution of daily measures from 5 days before to 5 days after the ICH occurred. For 1) and 2), the statistical significance of the results was determined with a Monte Carlo simulation combined with a resampling technique (1000×). RESULTS: Regarding all patients, no statistically significant and meteorologically meaningful signal could be found. With respect to subgroup-analysis, ICH related to vascular pathologies occurred significantly more frequently at days with especially low relative humidity, whereas an opposite relation was present in patients with cerebral amyloid angiopathy. However, as absolute deviations were small, a strong functional effect is questionable. With respect to seasonal distribution, a greater incidence of ICH could be detected during the cold season, in line with previous reports. CONCLUSIONS: By using high-quality meteorological data analyzed with a sophisticated and robust statistical method that minimizes the confounding effect of seasonality, no clearly identifiable meteorological influence for the ICH events considered can be found.
OBJECTIVE: To investigate the influence of meteorological factors on the incidence of intracerebral hemorrhage (ICH). METHODS: We included 295 ICH admissions between 2005 and 2013. The hourly meteorological parameters considered were surface pressure, temperature, relative humidity, wind gusts, and precipitation. To minimize confounding effects of seasonality, data were analyzed with the following 3 complementary statistical approaches: 1) deviation of daily measure from the 10-year monthly mean at the day of ictus; 2) deviation from monthly average with respect to changes in daily measures between the day of ictus and 2 days before; and 3) evolution of daily measures from 5 days before to 5 days after the ICH occurred. For 1) and 2), the statistical significance of the results was determined with a Monte Carlo simulation combined with a resampling technique (1000×). RESULTS: Regarding all patients, no statistically significant and meteorologically meaningful signal could be found. With respect to subgroup-analysis, ICH related to vascular pathologies occurred significantly more frequently at days with especially low relative humidity, whereas an opposite relation was present in patients with cerebral amyloid angiopathy. However, as absolute deviations were small, a strong functional effect is questionable. With respect to seasonal distribution, a greater incidence of ICH could be detected during the cold season, in line with previous reports. CONCLUSIONS: By using high-quality meteorological data analyzed with a sophisticated and robust statistical method that minimizes the confounding effect of seasonality, no clearly identifiable meteorological influence for the ICH events considered can be found.