Background. Little is known about the risk of occupational asthma or its ca
usative agents in South Africa. The objective of this study was to determin
e the proportion of adult asthmatics whose asthma may be occupational, and
the main agents or occupations involved.
Design and setting. A descriptive surveillance study of adult patients pres
enting with acute asthma to the casualty units of two large public hospital
s in Cape Town.
Methods. A brief questionnaire was completed by the casualty staff for a sa
mple of 140 adult asthmatic patients. Respondents were classified as having
possible occupational asthma on the basis of adult-onset asthma, exposure
at time of onset to a known or suspected cause of occupational asthma, and
symptoms that improved away from work.
Results. Eighteen patients (12.9%, 95% confidence interval (CI) 7.8 - 19.6%
) met the criteria for occupational asthma. The main occupational categorie
s in this group were spray painters (4 patients) and domestic workers (4 pa
tients) with cleaning agents, dyes and Faints being the most commonly repor
ted exposures. A total of 36 patients (25.7%, 95% CI 18.7 - 33.7%) reported
work aggravation of their asthma.
Conclusions. A clinically significant proportion of adult-onset asthmatics,
men and women, may have occupational causation, while an even larger propo
rtion may have occupational aggravation. Since early intervention favourabl
y; influences prognosis in occupational asthma, all practitioners dealing w
ith adult asthmatics should explore occupational factors.