Regional distribution of asthma-related hospital treatment periods in Finland in 1972-86.

We examined the use of asthma-related hospital services in geographically different areas of Finland in 1972-86, using data obtained from hospital discharge registers. A total of 254,402 cases diagnosed as asthma was identified (diagnosis 493, International Classification of Diseases, 8th Revision), information on the patient's place of residence enabling comparison of the southern, western, eastern, and northern parts of the country. Annual hospitalizations and the occurrence of new cases were calculated relative to the population, the former being found to increase throughout the country during the period studied, the most marked rise being 8.8% in Northern Finland (95% confidence interval 6.4-11.3%), and the smallest, 1.1%, in Western Finland (-0.2 to +2.5). A corresponding trend was also noted in the annual occurrence of new cases, which increased most in Northern Finland, i.e. by 4.8% (3.0-6.6), and decreased in Western Finland by 2.9% (-3.6 to -2.1). The change in asthma and the organization of treatment and factors related to the cold environment may, in combination, contribute to difficulties in the treatment of asthma in Northern Finland.