During military service young men (age 19–21 years) are exposed to many predisposing factors for asthma. We aimed to study the short-term prognosis of asthma after the military service.

All 216 men with verified asthma in 2004–2005 from the register of the Central Military Hospital were included in the study. A questionnaire was mailed to them in autumn 2007 and the 146 responders (68%) formed the final study population. Asthma severity was evaluated during military service according to the medical records of the subjects and two years later based on the questionnaire using modified GINA guidelines. The results on lung function and allergy tests during military service and asthma history were used as predictors of asthma severity at two-year follow-up.

Two groups of asthmatics were identified: those who already had asthma when entering the military service (n=71, 48.6%) and those, who had a new onset of asthma during the service (n=75, 51.4%). Overall asthma was less severe at two-year follow-up than during military service (p=0.036). Both during military service and at two-year follow-up, asthma was milder among the men, who had a new onset of asthma during military service. Atopy (p=0.002), number of positive skin-prick tests (p=0.005) and higher total serum IgE (p=0.001) were significant predictors for persistent asthma at follow-up.

Asthma, which had aggravated or started during military service, was significantly less severe two years later. The degree of atopy was a major determinant of the two-year prognosis of asthma after military service.