Incidence of occupational asthma and persistent asthma in young adults has increased in Finland.

To investigate the incidence of occupational asthma and its relationship to new cases of persistent asthma, the data was collected from two national registers which cover practically all new cases of both diseases. In 1986 to 1993, the annual incidence of persistent asthma in adults (from 15 to 64 years) increased from 6,645 to 8,056 (21%). The incidence of asthma in women increased from 3,302 to 4,717 (43%). In the age group of 15 to 29 the increase was 91%, in 30 to 49 it was 60%, and in 50 to 64 the increase was 7%. Among men, the annual incidence remained stable. However, in the age group of 15 to 29 it increased by 87%, in 30 to 49 by 46%, while a decrease of 43% was detected in the age group of 50 to 64 years. During the same period, the annual incidence of occupational asthma increased from 227 to 386 (70%), from 109 to 185 (70%) in women and from 118 to 201 (70%) in men. In 1993 the population in Finland in the age range from 15 to 64 was 2.026 million. Thus, the incidence of persistent asthma was 0.4%. The proportion of newly diagnosed occupational asthma out of all new cases of asthma was 4.8%.