Abstract:

Based on the daily data on stroke morbidity and meteorological data in Lanzhou during 2010-2013, the association between temperature and the morbidity of stroke among the population was addressed using the distributed lag non-linear model, and the possible impacts of different temperature and different lag days on stroke morbidity were analyzed. The results show a close association between stroke morbidity and the meteorological factors. Analysis of correlation between the meteorological factors and patient characteristics of stroke show the daily number of stroke cases is correlated with temperature, atmospheric pressure and relative humidity. Temperature presented non-linear association with stroke over different lag days. Different types of stroke vary in their strength of association with temperature. For patients with cerebral hemorrhage, low temperature would demonstrate hazardous effect, the risk of morbidity would constantly rise with the increasing lag days before reaching the peak at 2?3 lag days, and could persist through 30 days after the occurrence of low temperature. The course of cerebral infraction presented certain differences from that of cerebral hemorrhage. Both high and low temperature could increase the risk of morbidity, and the temperature effect would occur on the same day and reach the peak within 3?5 lag days. Low temperature had greater impacts on women or those aged 19?64 years, while high temperature had greater impacts on those ≥65 years old. Low temperature had impacts on morbidity of various types of stroke, while high temperature only had impacts on morbidity of ischemic stroke. The impacts of temperature on stroke morbidity vary in different age groups and gender, and in different types of stroke. Temperature acts as an external etiological factor by affecting the organism’s functions.

Key words: meteorological factors, stroke, lag effects, Lanzhou city