Am. J. Respir. Crit. Care Med., Vol 154, No. 5, Nov 1996, 1394-1400.
An epidemiologic investigation of asthma in welders
JR Beach, JH Dennis, AJ Avery, CL Bromly, RJ Ward, EH Walters, SC Stenton and DJ Hendrick
Department of Respiratory Medicine, Newcastle General Hospital, University of Newcastle upon Tyne, United Kingdom.
To clarify whether asthma may be caused by fume from welding mild steel and
to evaluate the possible strength of such an effect, we quantified airway
responsiveness among young shipyard workers with different levels of fume
exposure. Clinical investigation comprised a cross- sectional survey of 19-
to 27-yr-old workers who were completing 3 to 9 yr of employment in various
trades, and a control group of 15- to 17-yr- old school leavers who were
applying for apprenticeships within the same trades. Both groups were
subdivided into negligible-, ambient-, or high-exposure subgroups according
to expected levels of fume exposure. Actual exposures were assessed in a
parallel environmental survey. Participants were investigated by
questionnaire, skin prick tests, spirometry, and methacholine tests.
Complete data sets were obtained from 1,024 of the 1,070 eligible subjects
(96%). Among the workers but not the school leaver controls, there was an
increasing prevalence of positive methacholine tests across the exposure
subgroups-negligible 37%, ambient 44%, high 49% (p < 0.05). Regression
analyses showed that in males after allowing for the effects of atopy,
current smoking, and age, the estimated geometric mean level of airway
responsiveness of regular welders was twice that of workers with negligible
exposure after 5 yr of work. This implies that fume exposure may have been
critical in causing asthma in about 1% of the welders. A lesser effect
(though not significantly so) was noted among the workers with ambient
exposure.
