Date of birth and the incidence of acute ischemic stroke in Hungary

INTRODUCTION. The effect of the date of birth on the incidence of cardiovascular disease was confirmed in earlier studies. We aimed to determine whether the season of birth may be associated with a higher incidence of stroke in later life by analyzing thrombolysis numbers according over a ten-year period in Hungary. PATIENTS AND METHODS. We analyzed daily thrombolysis numbers between 2007 and 2016 according to the patients’ date of birth based on seasons. The correlation between cumulative thrombolysis numbers between 2007 and 2016 per month and birth numbers per month based on data of the 1949 census were also examined. RESULTS. Our results indicate that being born in the spring and summer in the northern hemisphere may be associated with a higher frequency of ischemic stroke necessitating thrombolytic treatment. This equates to a higher risk when conception and early pregnancy occur in the summer and autumn months. CONCLUSIONS. This, however, cannot be defined as a causal relationship if we consider the number of live births in 1949, as both measures change similarly during the year, as indicated by the strong positive correlation between thrombolysis frequency according to date of birth between 2007 and 2016 and the number of births in the 1949 census by month.