Background and purpose: Previous reports have established that the incidence of stroke may be influenced by meteorologic variations. However, no significant correlation was clearly demonstrated concerning aneurysmal bleeding.
Methods: From January 1, 1989, to December 31, 1991, 238 patients with angiographically confirmed diagnoses of subarachnoid hemorrhage were registered in the North of France region. For each day, the weather variables were provided by the national meteorologic office (Meteo France). We compared the meteorologic variables of days when subarachnoid hemorrhage occurred with the variables of days without subarachnoid hemorrhage in a multivariate model.
Results: We observed a seasonal pattern in the occurrence of subarachnoid hemorrhage, with a low frequency of rupture in June and July and maximum frequency in April and September (P < .05). The days of occurrence were associated with short duration of sunshine (P < .00006), low minimal level of hygrometry (P < .0002), low maximal temperature (P < .005), and low atmospheric pressure the day before the event (P < .05).
Conclusions: Aneurysmal bleeding was significantly associated with weather variables. Cold-induced hypertension may explain these fluctuations in the occurrence of aneurysmal bleeding.