Occupational asthma due to gas metal arc welding on mild steel

Occupational rhinitis due to steel welding fumes

Exposure to welding fumes is a recognized respiratory hazard. Occupational asthma but not occupational rhinitis has been documented in workers exposed to steel welding fumes. We report a 26-year-old male with work-related rhinitis symptoms as well as lower airways symptoms suggestive of occupational asthma and metal fume fever associated with exposure to steel welding fumes. The diagnosis of occupational rhinitis was confirmed by specific inhalation challenge.

Redemption of asthma pharmaceuticals among stainless steel and mild steel welders: a nationwide follow-up study

PURPOSE

The purpose was to examine bronchial asthma according to cumulative exposure to fume particulates conferred by stainless steel and mild steel welding through a proxy of redeemed prescribed asthma pharmaceuticals.

METHODS

A Danish national company-based historical cohort of 5,303 male ever-welders was followed from 1995 to 2011 in the Danish Medicinal Product Registry to identify the first-time redemption of asthma pharmaceuticals including beta-2-adrenoreceptor agonists, adrenergic drugs for obstructive airway diseases and inhalable glucocorticoids. Lifetime exposure to welding fume particulates was estimated by combining questionnaire data on welding work with a welding exposure matrix. The estimated exposure accounted for calendar time, welding intermittence, type of steel, welding methods, local exhaustion and welding in confined spaces. Hazard ratios (HRs) with 95% confidence intervals (CIs) were calculated using a Cox proportional hazards model adjusting for potential confounders and taking modifying effects of smoking into account.

RESULTS

The average incidence of redemption of asthma pharmaceuticals in the cohort was 16 per 1,000 person year (95% CI 10-23 per 1,000 person year). A moderate nonsignificant increased rate of redemption of asthma medicine was observed among high-level exposed stainless steel welders in comparison with low-level exposed welders (HR 1.54, 95% CI 0.76-3.13). This risk increase was driven by an increase risk among non-smoking stainless steel welders (HR 1.46, 95% CI 1.06-2.02). Mild steel welding was not associated with increased risk of use asthma pharmaceuticals.

CONCLUSION

The present study indicates that long-term exposure to stainless steel welding is related to increased risk of asthma in non-smokers.

Current topics in occupational asthma

The study of occupational asthma (OA) provides insights into asthma in general, as the cause is known. The relationships between the cause and response can be measured and modifying factors can be identified and their influence quantified. Developing OA has much more serious consequences for the patient than new onset asthma unrelated to work exposures, as the patient's livelihood is nearly always affected. Many healthcare professionals are more ready to accept and act on asthmatic symptoms when they are unrelated to work than when work may be the cause; antagonism can also occur in the workplace. This article reviews some of the areas where development and controversy enrich the study of OA. It makes no attempt to be comprehensive.

Bronchial asthma and COPD due to irritants in the workplace - an evidence-based approach

BACKGROUND

Respiratory irritants represent a major cause of occupational obstructive airway diseases. We provide an overview of the evidence related to irritative agents causing occupational asthma or occupational COPD.

METHODS

We searched MEDLINE via PubMed. Reference lists of relevant reviews were also screened. The SIGN grading system was used to rate the quality of each study. The modified RCGP three-star system was used to grade the body of evidence for each irritant agent regarding its causative role in either occupational asthma or occupational COPD.

RESULTS

A total of 474 relevant papers were identified, covering 188 individual agents, professions or work-sites. The focus of most of the studies and the predominant diagnosis was occupational asthma, whereas occupational COPD arose only incidentally.The highest level assigned using the SIGN grading was 2+ (well-conducted systematic review, cohort or case-control study with a low risk of confounding or bias). According to the modified RCGP three-star grading, the strongest evidence of association with an individual agent, profession or work-site ("**") was found for 17 agents or work-sites, including benzene-1,2,4-tricarboxylicacid-1,2-anhydride, chlorine, platinum salt, isocyanates, cement dust, grain dust, animal farming, environmental tobacco smoke, welding fumes or construction work. Phthalic anhydride, glutaraldehyde, sulphur dioxide, cotton dust, cleaning agents, potrooms, farming (various), foundries were found to be moderately associated with occupational asthma or occupational COPD ("*[+]").

CONCLUSION

This study let us assume that irritant-induced occupational asthma and especially occupational COPD are considerably underreported. Defining the evidence of the many additional occupational irritants for causing airway disorders will be the subject of continued studies with implications for diagnostics and preventive measures.

Metal-induced asthma and chest X-ray changes in welders

OBJECTIVES

The aim of this study was to evaluate the coexisting factors and usefulness of diagnostic methods in metal-induced asthma in Polish welders.

MATERIALS AND METHODS

Examination of 50 welders occupationally exposed to metals and with suspicion of metal-induced asthma (group A), 100 welders occupationally exposed to metals but without suspicion of metal-induced asthma (group B), and two control groups (10 patients with atopic asthma and 10 healthy subjects) was carried out. Questionnaire survey, clinical examination, skin prick tests to common aeroallergens and metal salts, rest spirometry tests, X-ray, metacholine challenge and a single-blind, placebo controlled specific inhalation challenge tests with metals (or work-like conditions challenge tests) were performed.

RESULTS

In group A--in 9 cases we obtained positive results of specific inhalation challenge tests with metals (in 3 cases with nickel, in 4 cases with chromium, in 1 case with cobalt and in 1 case with manganese). Nine cases of metal-induced occupational asthma were recognized. In group B--only in one case we obtained positive results of work-like conditions challenge test (clinical and spirometry changes, eosinophil influx in induced sputum), which confirmed the diagnosis of occupational asthma. In most of examined welders (62%), pulmonary changes in chest X-ray images were noted. The statistical analysis revealed that working as a welder for more than 10 years is the coexisting factor of presence of chest X-ray changes (p- or q-type nodular changes or interstitial changes). Positive results of skin prick tests with metal salts were the coexisting factors of occupational asthma due to metals among examined group of welders.

CONCLUSIONS

Specific inhalation challenge plays the key role in diagnostics of metal-induced asthma in welders. Pulmonary changes in chest X-ray were found in a significant percentage of examined welders.

Is metal fume fever a determinant of welding related respiratory symptoms and/or increased bronchial responsiveness? A longitudinal study

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.

Prevalence and association of welding related systemic and respiratory symptoms in welders

BACKGROUND

The prevalence of welding related respiratory symptoms coexisting with welding related systemic symptoms in welders is unknown.

AIMS

To determine in a sample of welders the prevalence of coexisting welding related systemic symptoms indicative of metal fume fever (MFF) and welding related respiratory symptoms suggestive of occupational asthma (OA), and the strength and significance of any association between these two groups of symptoms.

METHODS

A respiratory symptoms questionnaire, a systemic symptoms questionnaire, and a questionnaire on occupational history were administered by telephone to 351 of a sample of 441 welders (79.6%) from two cities in Québec, Canada.

RESULTS

The co-occurrence of possible MFF (defined as having at least two symptoms of fever, feelings of flu, general malaise, chills, dry cough, metallic taste, and shortness of breath, occurring at the beginning of the working week, 3-10 hours after exposure to welding fumes) together with welding related respiratory symptoms suggestive of OA (defined as having at least two welding related symptoms of cough, wheezing, and chest tightness) was 5.8%. These two groups of symptoms were significantly associated (chi(2) = 18.9, p < 0.001).

CONCLUSION

There is a strong association between welding related MFF and welding related respiratory symptoms suggestive of OA. As such, MFF could be viewed as a pre-marker of welding related OA, a hypothesis that requires further investigation.

Bronchial reactions to exposure to welding fumes

OBJECTIVES

To study the airway response and its mechanism to welding fumes in six welders with respiratory symptoms.

METHODS

Methacholine and welding challenge tests were carried out. The concentration of welding fumes during the exposure test was measured. On two subjects who developed bronchoconstricition to welding challenge, additional tests were carried out including prick, patch, and inhalation challenges with metal salt solutions.

RESULTS

Three subjects developed immediate bronchial reaction to exposure to welding fume; one to mild steel and stainless steel welding, another to mild steel and galvanised welding, and one only to galvanised welding. They all had a moderate to pronounced degree of non-specific bronchial hyperresponsiveness. The concentration of fumes during welding tests, particularly to galvanised welding, was high. An inhalation challenge test with zinc chloride salt solution in two subjects who reacted to galvanised welding was negative. Prick and patch tests with zinc chloride were also negative.

CONCLUSION

The airway response to welding in these subjects is non-specific and is due to irritation rather than to sensitisation.