LAUSR

Welders are exposed through welding fume to particles and metals, including nickel and chromium, that may act as respiratory sensitizers. In a Canadian study of male and female welders we investigated the relation of modelled welding exposures to episodes of asthma/wheeze and rhinitis. Welders who had been registered in an apprenticeship were recruited and followed up at 6-month intervals for up to five years. Women were recruited from across Canada, men just from Alberta. At each contact participants were asked about their health and specifically about symptoms of asthma and rhinitis and age these had first occurred. A complete job history was taken and at each contact after recruitment the participant completed a detailed welding task questionnaire. A job exposure matrix was developed, reflecting type of welding, base metal and consumables. This was validated against urinary metal concentration. 1001 welders, including 447 women, were recruited. In bivariate analyses, hours of welding/week, hours grinding/day and estimated exposures to total particles, manganese, nickel and aluminum were related to episodes of asthma/wheeze.  Hours welding, grinding and nickel exposure were related to rhinitis. In multivariable models, including all exposures and confounders, the number of hours welding/week and hours grinding/day were related to asthma/wheeze episodes and hours grinding and nickel exposure to rhinitis. Duration of welding tasks was related to episodes of asthma/wheeze and rhinitis. There was less evidence that estimated metal concentrations were associated with respiratory ill-health, having adjusted for hours welding.