Asthma Symptoms
The asthma symptom data at baseline, 6 and 12-month follow-up is summarized in Table II, including the available data on the 12 workers lost to follow-up during this 1 year follow-up period. The overall prevalence of symptoms was low, and similar comparing baseline and the 2 follow-up times. However, a significantly higher proportion of workers lost to follow-up (3/12; 25%) reported current asthma-like symptoms, compared to those who remained enrolled in the study (1/37; 2.7%) (p=0.04). Considering only those workers no longer employed at the company, 1/6 (16.7%) reported current asthma symptoms compared to 3/43 (7.0%) of those still employed by the company, whether or not available for follow-up. Three workers (7.1%) reported new asthma-like symptoms during the study, including one worker who reported a temporal relationship of his symptoms with work at 6 months, and by 12 months had resigned and left the workplace.