Background: The fraction of exhaled nitric oxide (FENO) has been found reduced 4 to 6 weeks after an educational intervention in farmers with occupational asthma.

Objective: To reveal whether long-term changes in FENO would still be detectable a year after the intervention.

Methods: We evaluated airway inflammation and obstruction at baseline and after 1 year in animal farmers with occupational asthma (n = 43, 16 women, mean [SD] age, 46.5 [8.9] years) who participated in a 1-day educational program, and in a control group of farmers without intervention (n = 15, 3 women, mean age, 44.1 [10.7] years). FENO, spirometry results, and questionnaire data were compared between measurements and between the intervention and control group.

Results: In the intervention group, geometric mean (SEM) FENO decreased from 31.5 (1.1) to 25.0 (1.1) parts per billion (ppb) (P = .001), whereas in the control group there was a slight but not statistically significant increase from 27.2 (1.2) to 30.7 (1.2) ppb. Spirometric values remained unchanged in both groups.

Conclusions: We found that FENO was still decreased 1 year after an educational intervention in farmers with occupational asthma. It would thus seem that FENO, a noninvasive marker of airway inflammation that can be easily assessed in occupational field work, may be suitable for the evaluation of both short-term and long-term effects of preventive measures in occupational asthma.

Key words: Agriculture. Educational intervention. Exhaled nitric oxide. Farming. Occupational asthma.