AWS-EWH-11 pdf free download

AWS-EWH-11 pdf free download.Effects of Welding on Health, XI.
Health Effects Related to Duration of Welding Experience
Associations between exposures and effects are strengthened by observation of a positive dose-response relationship. If there are cumulative health effects, they would be expected to be more prevalent and more pronounced among those with longer welding experience. When detailed exposure histories and industrial hygiene measurements are unavailable, a welder’s length of employment in the profession is often used as an indication of the cumulative dose from exposure to welding fumes. A positive duration-effects relationship was found by Beach et al. (Refs. 13 and 14) in a study of young shipyard welders of mild steel who, during their first 9 years in the trade, showed changes in airways reactivity. These changes, which could be signs of progression toward the development of asthma, were related to years of employment as welders. Even though a positive relationship between exposure duration and effects is observed in a study, the findings may be distorted by confounding factors. Rocskay ci al. (Ref. 124) found increased radiographic abnormalities, respiratory symptoms, and deficits in lung function that were positively related to duration of employment in a group of ironworkers who performed welding and cutting, hut, as the authors stated, these effects could also have been related to smoking and to exposure to asbestos. In a study by Lauritsen and Hansen (Ref. 90), lung cancer mortality was significantly associated with duration of exposure to welding fumes up to 15 years but in welders with more than 15 years experience, the odds ratios for lung cancer were not as large, and the differences between welders and nonwelders were no longer significant.
Several other investigators had less success finding relationships between years of welding and the incidence of health effects. Sobaszek et al. (Ref. 135) found a small deficit in midexpiratory flow rates associated with years of experience welding stainless steel, but there were no other duration-related effects for other populations of welders or in other lung function tests. Ozdemir (Ref. 109) found no differences in the frequency of chronic bronchitis or in lung function between groups of welders with more than or less than 20 years experience. Toren (Ref. 148) found a significantly higher incidence of self- reported asthma among welders than in the general population, but the incidence was highest among welders younger than 45 years old. Rossignol (Ref. 126) found no association of lung function with welding fume exposure except among welders older than 45. who performed better in lung function tests than did younger, less experienced welders. Holly et al. (Ref. 69) found a significantly increased risk ftr uveal melanoma (cancer of the eye) among welders that was unrelated to years of welding experience. The possibility that a single severe burn to the eye may be associated with an increased risk for this cancer may explain the lack of a relationship between the risk for eye cancer and the duration of the welding experience.
The most commonly offered explanation for the scarcity of evidence for a cumulative effect of welding exposure is that workers who are affected by their working environment are prone to migrate to other employment. This is an often-cited hypothesis in the case of occupational asthma, where respiratory problems may develop before the onset of clinical asthma. Evidence in support of this phenomenon is provided by the finding of Chinn et al. (Ref. 32) that significantly more of those who were unavailable for a follow-up health assessment had reported having respiratory symptoms when examined 7 years earlier than had those who were available for the second examination. Although lung cancer is an insidious disease, Lauritsen and Hansen (Ref. 90) also cited the migration effect as an explanation for their failure to find an increased lung cancer risk related to duration of exposure past 15 years.AWS-EWH-11 pdf download.