Influence of the atmospheric pressure and other variable weather on the incidence of the subarachnoid hemorrhage

Spontaneous subarachnoid hemorrhage is a pathology usually related to risk factors, such as arterial hypertension and/or nicotine poisoning. Nevertheless, other variables exist, like meteorological changes, that although the experience aims as possible responsible for an increase of the incidence, are still not established like such. It is to investigate the influence of the meteorological changes, either seasonal variations or changes of atmospheric pressure, in the incidence of the subarachnoid hemorrhage. All the cases of spontaneous subarachnoid hemorrhage are considered from the 1st of January from 1997 to the 31st of March of 2008, making a medical registry of demographic aspects (age, sex) and antecedents (arterial hypertension, diabetes mellitus, cerebral ischemia, nicotine poisoning), as well as numbers of atmospheric pressure (in hectopascales, hPa), daily temperature and relative humidity, throughout this period, with a calculation of the maximum, average and minimum values, as well as pressure differentials between consecutive days. The analysis of the 173 gathered cases showed a predominance of the subarachnoid hemorrhage in female, specially the aneurismal ones, being arterial hypertension, the main factor of related risk. Significant differences between the days with and without hemorrhage were not demonstrated, in relation to the variation of atmospheric pressure (p 0.463), pressure temperature (p 0.381) and relative humidity (p 0.595) throughout the day. In our element, the variations of atmospheric pressure are not related to an increase of incidence of the subarachnoid hemorrhage. Instead of this, cases of subarachnoid hemorrhage take place with changes of hardly 1.7 (1-3) hPa in the day, without observing a clear seasonal tendency.