Physician reports of work-related asthma in California, 1993-1996.

Background: Work-related asthma is a leading cause of occupational respiratory illness.
Methods: Work-related asthma was studied in California over a 36-month period, from March 1, 1993 to February 29, 1996. The surveillance system identified cases from Doctor's First Reports (DFRs), a mandated physician reporting system. Structured follow-up telephone interviews of DFR asthma cases were conducted to collect work history, exposure, and medical information. Statewide employment data was used to calculate disease rates among industry groups.
Results: Based on 945 cases of work-related asthma, the average annual reporting rate for work-related asthma in California was 25/million workers. We estimate that the actual rate is 78/million, adjusted for likely underreporting. Janitors and cleaners (625/million) and firefighters (300/million) had the highest reporting rates of work-related asthma. Half of all work-related asthma cases were associated with agents not known to be allergens.
Conclusions: A greater proportion of work-related asthma associated with irritant exposures was identified than has previously been reported. The surveillance data provide a very conservative estimate of the incidence of work-related asthma.
(Copyright 2001 Wiley-Liss, Inc.)