Welding Effects Among Naive Subjects

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<<<<<<<<<<<<<<<< Is metal fume fever a determinant of welding relatedrespiratory symptoms and/or increased bronchial responsiveness? A longitudinal study
M El-Zein, C Infante-Rivard, J-L Malo, D Gautrin
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Occup Environ Med 2005;62:688–694. doi: 10.1136/oem.2004.018796

Background: The current prospective study investigated the hypothesis of metal fume fever (MFF) being a predictor for the development of respiratory symptoms and functional abnormalities.
Methods: The study consisted of a pre-exposure and two follow up assessments of 286 welding
apprentices during an average period of 15 months. A respiratory and a systemic symptom questionnaire, skin prick tests to common allergens and metal salts, spirometry, and methacholine challenge tests were administered.
Results: Developing at least one positive skin prick test to a metallic salt solution was found in 11.8% of apprentices. Possible MFF (at least one of fever, feelings of flu, general malaise, chills, dry cough, metallic taste, or shortness of breath) was reported by 39.2% of apprentices. The presence of at least one welding related respiratory symptom (cough, wheezing, or chest tightness) suggestive of welding related asthma was reported by 13.8%. MFF was significantly associated with these respiratory symptoms (OR = 4.92, 95% CI 2.10 to 11.52), after adjusting for age, atopy, smoking, physician diagnosed asthma, and symptoms of non-welding related asthma. Apprentices with possible MFF, and no welding related respiratory symptoms suggestive of welding related asthma at the first follow up, had an increased risk of developing the latter symptoms by the second follow up visit (OR = 7.4, 95% CI 1.97 to 27.45) compared with those not having MFF. MFF was not significantly associated with an increase in bronchial responsiveness.
Conclusion: MFF could be a predictor for the development of respiratory symptoms but not for functional abnormalities in welders.

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BrooklynDodger Comments: An inception cohort shows clearly the effects of routine welding exposures.

These are students in 4 vocational training centers in Montreal, observed for up to 18 months. The details of their exposure regimen are found in the full paper, but it's about 2 months of welding work, according to the investigators.

No exposure data was provided by the paper.

Metal fume fever victims outnumbered those with asthma symptoms 3 to 1. MFF predicted symptoms.

This is a very short exposure. Presumably the apprentices with more severe symptoms, either MFF or asthma, will drop out of the profession, so the full risk of exposure would not be seen in a more experienced population.