[The seasonal dynamics of morbidity of acute lymphoblastic leukemia in Azerbaijan]

The article presents results of assessment of seasonal dynamics of morbidity rate of acute lymphoblastic leukemia among population younger than 29 years old in Azerbaijan. The materials of Scientific and Research Institute of Hematology and Transfusiology were used, including data of National register of acute lymphoblastic leukemia. The observation had been realized retrospectively and covered data of 991 patients younger than 29 years old in 1998-2014. According used data, all patients were distributed according to seasons. The inter-seasonal differences in the cases of acute lymphoblastic leukemia were estimated by single-factor analysis of variance. During 1998-2014 number of acute lymphoblastic leukemia cases changed within the interval 10 - 20 in Spring, 10-27 in Summer, 10-29 Autumn and 8-19 cases in Winter. The median of cases of acute lymphoblastic leukemia consisted 13,3 in Spring, 15,4 in Summer, 13,7 in Autumn and 10 in Winter. The average number of cases of acute lymphoblastic leukemia in Spring was (15,49±1,13), in Summer (15,89±1,08) and in Autumn (15,71±1,21) practically were equal (р>0,05) and was significantly (р<0,05) higher than the same data in Winter (11,07±0,76). In total, during 1998-2014 number of acute lymphoblastic leukemia cases in Summer was higher than the same number in Winter up to 1,24 times. The risk of the incidence of acute lymphoblastic leukemia earlier than age of 29 years in Winter in Azerbaijan is relatively low. The increase of morbidity risk of acute lymphoblastic leukemia is specific for Spring, Summer and Autumn are at the same degree. The seasonal risks of acute lymphoblastic leukemia morbidity are not universal. They change depending on conditions of the year. The seasonal risks of acute lymphoblastic leukemia morbidity are better to be assessed comparing morbidity cases per seasons of a year (winter, spring, summer and autumn), but not according summary of winter and summer seasons.