Study objectives: To assess the prevalence of a
historical occupational component to asthma in an adult asthma clinic
and to compare characteristics of asthmatic subjects with and without
Design: A retrospective
review of data obtained from a physician-administered questionnaire,
answers to which were obtained at the initial patient visit of
asthmatic subjects, and which included specific questions regarding the
relationship of work to symptoms. Chart review data were used to
supplement information on workplace exposures and investigations.
Setting: A university-based secondary- and
tertiary-referral asthma clinic.
hundred thirty-one adult asthmatic subjects who were referred for
assessment and management of asthma.
Statistical analyses of asthmatic subjects with and without
work-attributed symptoms and a determination, from chart review, of the
likelihood of causes for symptomatic worsening of asthma at work.
Measurements and results: Sixty percent of the patients
(435) had adult onset of asthma, among whom 310 patients (71%) were
employed at the time of their visit. Fifty-one patients reported their
asthma to be worse at work (ie, 16% of adult-onset
working asthmatic subjects). Sixteen of these patients (31%) had
likely or possible sensitizer-induced occupational asthma (OA), and
49% likely had aggravation of underlying asthma. The other 20% of
patients had possible OA or aggravation of underlying asthma at
Conclusions: Adult-onset asthmatic subjects
commonly report a worsening of asthma at work, more commonly on the
basis of likely aggravation of underlying asthma than on the basis of
likely or possible OA.