Different labelling of obstructive airway diseases in Estonia, Finland, and Sweden.

Large differences in prevalence of asthma have been reported between westernised countries and the former Eastern European countries, and still no consensus about the reasons for the differences exists. The aim of this study was to assess diagnostic labelling of obstructive airway diseases, comparing subjects with respiratory symptoms and the diagnoses obtained in Estonia, Finland, and Sweden. A postal questionnaire was sent to population-based random samples, and 44,483 (76%) answers were obtained from the 58,661 invited in 1996. Among men, current smoking was most common in Estonia, 60%, followed by Finland, 39%, and Sweden, 28%. In all three countries, 30% of women were current smokers. Most respiratory symptoms including wheezing were most common in Estonia, also among non-smokers. The prevalence of asthma was 2.0% and chronic bronchitis 10.7% in Estonia, while the opposite was found in Sweden with an asthma prevalence of 7.8% and a chronic bronchitis prevalence of 3.1%. The pattern in Finland was similar to that of Sweden. The same differences between the three countries were found also among young subjects. The total proportion of diagnosed obstructive lung diseases in subjects with respiratory symptoms was similar, but the diagnosis of asthma was considerably more common in Finland and Sweden. Chronic bronchitis was favoured in Estonia, also among young adults irrespectively of what symptoms were present. In a multivariate model with correction for confounders, the risk (OR) for having a diagnosis of asthma was 5.65 (95% CI: 4.86-6.56) when living in Sweden, and 3.51 (95% CI: 3.00-4.12) in Finland, whereas risk for chronic bronchitis was 0.28 (0.25-0.31) and 0.22 (0.19-0.25), respectively, compared to Estonia. The study indicates differences in diagnostic practices of obstructive lung diseases between the three countries.