A population-based study of the associations of stroke occurrence with weather parameters in Siberia, Russia (1982-92)

Previous studies have established a seasonal variation in stroke occurrence , but none have assessed the influence of inclement weather conditions on s troke incidence in a general population of Russia. We performed a stroke po pulation-based study in the Ohtiabrsky District of Novosibirsk, Siberia, Ru ssia. Included in the analysis were 1929 patients with their first occurren ce of ischemic stroke (IS), 215 patients with their first occurrence of int racerebral hemorrhage (ICH) and 64 patients with their first occurrence of subarachnoid hemorrhage (SAH): all patients were aged between 25 and 74 yea rs. The cumulative daily occurrence of total strokes and stroke subtypes wa s evaluated ill relation to aggregated daily mean values of ambient tempera ture. relative humidity and air pressure by means of Poisson regression ana lysis to estimate the rate ratio (RR) with corresponding confidence interva l (CI) and to identify the weather parameters of most importance. In a mult ivariate analysis, with adjustment for the effects of season, solar and geo magnetic activity, and age of the patients, low ambient temperature (RR 1.3 2; 95% CI 1.05-1.66) and mean value of air pressure (RR 0.986; 95% CI 0.972 -0.999) were important predictors of IS occurrence, while mild ambient temp erature (RR 1.52; 95% CI 1.04-2.22) was an important predictor of ICH occur rence. No relationship between SAH occurrence and any one of the weather pa rameters studied was revealed. There was no interaction between any meteoro logical variables that was statistically significant. Inclement weather con ditions are associated with the occurrence of IS and ICH in Siberia, Russia . Among the meteorological parameters studied, low ambient temperature and mean air pressure are the most important predictors of IS occurrence, where as the occurrence of ICH is associated with mild ambient temperature. There is no association between any one of the weather parameters studied and th e occurrence of SAH.