Objectives. To determine whether asthma in goldminers is caused by or
contributed to by their working environment. Design. A case-control st
udy in which men with asthma working underground in goldmines were com
pared with underground goldminers without asthma in relation to their
age, duration of exposure to the underground environment, atopy and fa
mily history of asthma. Setting. An in- and outpatient facility provid
ing for the medical needs of approximately 90 000 miners employed on g
oldmines in the Free State. Outcome measures. Occupational history, at
opy and family history of asthma were compared in the two groups, The
age of onset of asthma and duration of occupational exposure were exam
ined in the men with asthma. Results. The study sample included 78 und
erground miners with asthma and 46 without asthma. The men in the two
groups were of similar age, but those with asthma had worked undergrou
nd for a longer period than the men without asthma. Twenty of the asth
matic and none of the control group had been exposed to paint and ceme
nt in the course of their work, Fifty of the asthmatic and only 3 of t
he control group were atopic, The mean age of onset of asthma (+/- SD)
was 30.6 +/- 10.73 years. Six of the men had developed asthma before
starting to work in the mines, and the disease had developed 13.4 +/-
8.22 years after starting to work underground in the remaining 72. Con
clusion. The late age of onset and the onset after exposure to the und
erground environment suggest that the disease was work-related.