Iowa Asthma Follow-Up Study

The original Iowa study was extended to collect physical examination data on a subset of the telephone survey participants to validate the self-report of asthma. Data were collected on 32 Gulf War veterans who reported asthma during the telephone survey, 42 Gulf War veterans who reported no illnesses during the telephone survey, and 20 non-Gulf War veterans who reported asthma during the telephone survey. The two groups of subjects with reported asthma were similar in symptoms, baseline pulmonary function tests, and bronchial hyperreactivity. The Gulf War veterans who reported asthma had significantly more current symptoms compared with the Gulf War veterans who reported no illness during the telephone survey. They also had comparatively lower baseline spirometry (a measure of how well the lungs exhale) and increased bronchial hyperreactivity. No differences in smoking history were found between the two groups with asthma. However, Gulf War veterans who reported asthma were more likely to be current and past smokers than the Gulf War veterans who did not report illness.