title: Epidemiological situation of tuberculosis in Poland: part II. What are the causes of the different epidemiological situation in various regions of Poland?
abstract: BACKGROUND
  The different epidemiological situation of tuberculosis in various regions of Poland (higher and lower notification rates) was described previously by our group. The patients diagnosed with tuberculosis in the higher notification rate areas were younger and there were more cases of primary tuberculosis (tuberculous pleurisy and tuberculosis of chest lymph nodes) than in the patients diagnosed in the lower notification areas. The aim of the present study was to assess the possible causes of the different epidemiological situation of tuberculosis in various regions of Poland.
  
  
  METHODS
  Analysis was done at the same regions as in the previous paper. A comparison was made between two groups: Group I, which included three voivodeships with higher rates of notification, from 23.7 to 32.3/100,000 (mean rates in the analysed period of time); and Group II, which included five voivodeships with lower notification rates (mean rates from 12.2 to 18.6/100,000). The wealth of the regions (GDP, gross domestic product per capita), the level of unemployment, and social status of the patients were analysed. We compared the population density in both regions. The results of treatment in both regions were also analysed.
  
  
  RESULTS
  We did not find any differences in GDP and unemployment rates between the compared regions. The results of treatment were different in particular regions, but there was no clear tendency for worse results in voivodeships in Group I compared to voivodeships in Group II. However, the number of patients lost from observation was significantly higher in the regions from Group I than in those from Group II. There was also a significantly higher death rate from tuberculosis in younger patients (£ 59 years) from Group I than from Group II. This is additional proof that the epidemiological situation in the two regions was different. Finally, we found that the mean density of population in the regions from Group I was higher than that from Group II. The density of population may influence transmission of tuberculosis. There is also the possibility that the differences in the epidemiological situation in various regions of Poland are caused by historical events. In the past the epidemiological situation of tuberculosis was much worse in the east of Europe than in the west. Just after the Second World War, according to the changes of the Polish territory, many Polish citizens (mainly ancestors of those from Group I) were displaced from the east to the west.
  
  
  CONCLUSIONS
  In conclusion, the greater number of patients lost from observation, together with the higher density of population in the regions from Group I in comparison with those from Group II, seems to be partly responsible for the difference in the epidemiological situation in the two regions. It is also possible that some patients from Group I are more susceptible to infection and disease caused by Mycobacterium tuberculosis due to their ancestors, who lived in the east of Europe.
authors.forename: Ewa
authors.initials: E
authors.lastname: Rowińska-Zakrzewska
authors.affiliation: Department of Epidemiology and Control of Tuberculosis, National Tuberculosis and Lung Diseases Research Institute, Warsaw, Poland. m.korzeniewska@igichp.edu.pl.
authors.forename: Maria
authors.initials: M
authors.lastname: Korzeniewska-Koseła
authors.forename: Kazimierz
authors.initials: K
authors.lastname: Roszkowski-Śliż
mesh_terms: D017677:Age Distribution; D004196:Disease Outbreaks / Q000706:statistics & numerical data*; D009169:Mycobacterium tuberculosis / Q000302:isolation & purification; D011044:Poland / Q000453:epidemiology; D012042:Registries / Q000706:statistics & numerical data; D012111:Residence Characteristics; D012424:Rural Population / Q000706:statistics & numerical data*; D012959:Socioeconomic Factors; D014376:Tuberculosis / Q000175:diagnosis / Q000453:epidemiology*; D014505:Urban Population / Q000706:statistics & numerical data*