US EPA

6868410 

Journal Article 

Welding fumes and lung cancer: a meta-analysis of case-control and cohort studies 

Honaryar, MK; Lunn, RM; Luce, D; Ahrens, W; 'T Mannetje, A; Hansen, J; Bouaoun, L; Loomis, D; Byrnes, G; Vilahur, N; Stayner, L; Guha, N 

2019 

1 

Occupational and Environmental Medicine
ISSN: 1351-0711
EISSN: 1470-7926 

BMJ PUBLISHING GROUP 

LONDON 

76 

6 

422-431 

English 

30948521 

10.1136/oemed-2018-105447 

WOS:000471890100012 

https://www.scopus.com/inward/record.uri?eid=2-s2.0-85063989160&doi=10.1136%2foemed-2018-105447&partnerID=40&md5=10e35e23b01ffcad3c76aa76cb3aa2e2
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BACKGROUND: An estimated 110 million workers are exposed to welding fumes worldwide. Welding fumes are classified by the International Agency for Research on Cancer as carcinogenic to humans (group 1), based on sufficient evidence of lung cancer from epidemiological studies.

OBJECTIVE: To conduct a meta-analysis of case-control and cohort studies on welding or exposure to welding fumes and risk of lung cancer, accounting for confounding by exposure to asbestos and tobacco smoking.

METHODS: The literature was searched comprehensively in PubMed, reference lists of relevant publications and additional databases. Overlapping populations were removed. Meta-relative risks (mRRs) were calculated using random effects models. Publication bias was assessed using funnel plot, Eggers's test and Begg's test.

RESULTS: Forty-five studies met the inclusion criteria (20 case-control, 25 cohort/nested case-control), which reduced to 37 when overlapping study populations were removed. For 'ever' compared with 'never' being a welder or exposed to welding fumes, mRRs and 95% CIs were 1.29 (1.20 to 1.39; I2=26.4%; 22 studies) for cohort studies, 1.87 (1.53 to 2.29; I2=44.1%; 15 studies) for case-control studies and 1.17 (1.04 to 1.38; I2=41.2%) for 8 case-control studies that adjusted for smoking and asbestos exposure. The mRRs were 1.32 (95% CI 1.20 to 1.45; I2=6.3%; 15 studies) among 'shipyard welders', 1.44 (95% CI 1.07 to 1.95; I2=35.8%; 3 studies) for 'mild steel welders' and 1.38 (95% CI 0.89 to 2.13; I2=68.1%; 5 studies) among 'stainless steel welders'. Increased risks persisted regardless of time period, geographic location, study design, occupational setting, exposure assessment method and histological subtype.

CONCLUSIONS: These results support the conclusion that exposure to welding fumes increases the risk of lung cancer, regardless of the type of steel welded, the welding method (arc vs gas welding) and independent of exposure to asbestos or tobacco smoking. 

arc welding; exposure-effect analysis; gas welding; lung cancer; meta-analysis; meta-regression; mild steel welding; stainless steel welding; welding; welding fumes