Article Text


Welding and metals
Welding, lung function decline and respiratory symptoms: a systematic review of cohort studies
  1. Joanna Szram1,
  2. Susan Schofield1,
  3. Martin Cosgrove2,
  4. Paul Cullinan1
  1. 1Imperial College, London, UK
  2. 2Welding Institute, Cambridge, UK


Objectives While the acute health risks of welding are well understood and largely controlled, more chronic adverse effects - including those on lung function - are less clear. We carried out a systematic review of published longitudinal studies of lung function decline in welders.

Methods Through a search of electronic and bibliographic sources we reviewed and performed meta-analyses of original cohort studies (n=7, 892 welders) documenting two or more sequential measurements of lung function. The median duration of follow up was 5 years (range 2–18 years).

Results Reported FEV1 decline varied from -43.9 to -0.05 ml/year with a pooled estimate for all welders of -23.8 ml/year (95% CI -45.9 to -1.7). This was greater than in controls for whom the pooled estimate from five studies was -16.3 ml/year (95% CI: -30.6 to -2.0). Five of the eight studies analysed decline by smoking status: the pooled estimate for smoking welders was -34.6 ml/year (95% CI -59.0 to -10.2) and for non-smoking welders was -15.9 ml/year (95% CI -31.8 to 0.1). Equivalent estimates stratified by smoking for available control data were -17.3 ml/year (95% CI -34.0 to -0.6) and -14.0 ml/year (95% CI -32.5 to 4.5) for smokers and non-smokers respectively.

Conclusions Collectively, the available longitudinal data on decline of lung function in welders suggest a small effect that may be confined to those who smoke; they support a strong focus on smoking cessation. Further prospective studies are required to establish this finding. Epidemiologists with an interest in welding should consider a collaborative and carefully standardised longitudinal study of lung function in welding.

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