1. TRENDS IN HOSPITALIZATION RATES FROM ASTHMA IN CHILDREN AND ADOLESCENTS IN POLAND Krystyna Szafraniec 1, Wieslaw Jedrychowski 1, Bogdan Wojtyniak 2 and Pawel Gorynski 2 1 Chair of Epidemiology and Preventive Medicine, Jagiellonian University, Krakow, Poland 2 Department of Medical Statistics, National Institute of Hygiene, Warsaw, Poland

2. Background Asthma is considered as an allergic inflammation of airways, which causes bronchial obstruction. Nowadays, asthma is one of the common chronic disease in industrialised countries and its prevalence has increased worldwide over the last thirty years. Its prevalence varies markedly across the regions, possible risk factors have been identified that may explain the differences in asthma prevalence across countries or its rising trends.

3. Background Of the already recognized risk factors for asthma the strongest are a parental history of asthma and occurrence of other atopic diseases such as hay fever and eczema. The environmental factors include indoor allergens, environmental tobacco smoke, and possible changes in housing, diet and life style. There has been long debate about the possible role of ambient air pollution as a cause of increase in asthma. The evidence relating air pollution to asthmatic symptoms is still weak and inconsistent.

4. Background Though geographical trends of asthma in the world are clearly variable, numerous countries, independently of their economic status, have confirmed increasing prevalence of childhood asthma. The increase began in the 1970s and the range of increase doubled at least. Changes in prevalence of asthma ever diagnosed in children and young adults

5. Aims of the study To assess the time trends in hospitalization rates from asthma in children and adolescents below 19 years of age for the last 15 years in Poland Analyse geographical variation in hospitalization from asthma within the country Analyse geographical variation in hospitalization from asthma within the country

6. Material and Methods Data from individual hospital records were used to recognize the cause of hospitalization Morbidity ratios in 5-year age groups from asthma for years 1986-1999 were calculated Morbidity ratios in 5-year age groups from asthma for years 1986-1999 were calculated Linear regression method was applied to examine trends over time Linear regression method was applied to examine trends over time

7. Results Hospitalization rates from asthma in children and adolescents below 19 years of age showed a consistent rising trends. In the period 1984-1996 the rates doubled for both genders. Time trends were highly linear (p<0.001, R 2 =0.94). Hospitalization rates estimated by the regression analysis were 1.6-times higher for boys than girls. Hospitalization rates estimated by the regression analysis were 1.6-times higher for boys than girls. Mean annual increase was 12.2% for boys and 10.6% for girls. Mean annual increase was 12.2% for boys and 10.6% for girls.

8. Results Trends in hospitalization rates due to childhood asthma by age groups The most steep increase occurred in the children under 4 years of age (annually: 20.3% for boys and 18.9% for girls). In the age groups 5-9 yrs and 10-14 yrs mean annual gender- related increase range from 10.5 - 14.1%. In the age groups 5-9 yrs and 10-14 yrs mean annual gender- related increase range from 10.5 - 14.1%. Girls Boys Girls Boys

9. Results Trends in hospitalization rates due to childhood asthma by age groups The slowest increase was in the oldest age group (3.7% annually), however, linear trend in this group was statistically significant (p<0.001). Only in the oldest age group the differences in the rates were not gender- related. Only in the oldest age group the differences in the rates were not gender- related. Girls Boys Girls Boys

10. Results 161 - 290 121 - 160 90 - 120 missing Hosp. rate / 100 000 Geographical distribution of hospitalization rates due to asthma in 1999 by provinces was significantly variable compared with the average country rate. The highest overall rates in the northern part of Poland were observed. They were almost twice as high as the average country rate of 145/100 000. This trend remained stable for all age groups except for the children 14-19. The lowest hospitalization rates, representing 60-75% of country average were noted for the north- west provinces.

11. Summary The results show that hospitalization rates for children with asthma in Poland reflect linear increase over the last several years. The results show that hospitalization rates for children with asthma in Poland reflect linear increase over the last several years. The tendency was typical for the youngest age groups. The tendency was typical for the youngest age groups. Though hospitalization rates were significantly lower in girls than boys for each age group, the time trends in both groups increased similarly. Though hospitalization rates were significantly lower in girls than boys for each age group, the time trends in both groups increased similarly. The geographical variability of the hospitalization rates due to asthma in Poland is not compatible with the hygienic hypothesis of asthma and allergic diseases. The geographical variability of the hospitalization rates due to asthma in Poland is not compatible with the hygienic hypothesis of asthma and allergic diseases.