Bajram Dedja1, Alban Ylli1,2, Mimoza Dushkaj3
1 Institute of Public Health, Tirana, Albania;
2 Faculty of Medicine, University of Medicine, Tirana, Albania;
3 National Institute of Statistics, Tirana, Albania.
Aim: Non-communicable diseases (NCD) remain the leading cause of mortality and morbidity in our country, so it is necessary to study their frequency according to seasonal climatic conditions in addition to the burden of chronic diseases in the population. This study investigates the seasonal pattern of mortality and incidence of some NCDs, especially coronary heart disease (CHD), cerebrovascular accidents (CVA), tumors, etc.
Methods. Three main datasets were used for this study: 1) All fatal and non-fatal coronary events recorded during the year 2018. 2) Data from the National Registers of Ischemic Heart Diseases, CVA and Cancers. 3) Other data from hospital admissions. Total deaths and new cases of selected diseases for each of four season are compared between them. Seasons are defined by three complete months of the year.
Results. During seasons of the year, it was observed a systematic pattern of mortality from cardiovascular diseases, with higher rates in winter months. In summer months the frequency of deaths was the lowest. There were 312 less cases in summer (35.12% decrease) for CHD mortality, with respectively (894) deaths in winter and (580) deaths in summer months. The pattern was similar for CVA mortality with 28.27% less cases in summer compared to winter. The seasonal differences in morbidity of cardiovascular diseases were slightly different with the highest number of cases hospitalized in spring months. There were 16.3% more new CHD cases and 10.03% more new CVA cases in Spring compared to Summer. No seasonal pattern for cancers was observed.
Conclusions. The results showed that ischemic diseases and cerebrovascular disease have seasonality in both incidence and mortality. Possible explanations might be, higher vasoconstriction associated with lower winter temperatures and higher incidence of pulmonary conditions in colder months. These factors may interfere with health care seeking behavior and health system preparedness. Better knowledge on NCD’s seasonal variation may help health care providers to plan more effectively their services. The complex relationships between climate and diseases need more research in the future.
Keywords: Non-Communicable Diseases, Mortality, Seasonal variation.