Cochrane review suports complete removal from exposure in workers with occupational asthma

This is a further evidence-based review supporting complete removal from exposure over exposure reduction 

The authors grade the quality of evidence as very low using Cochrane methodology, and make the following recomendations for future research into outcomes of occupational asthma including randomisation of workers into removal from exposure or exposure reductionable. It would need a very special employment situation to be able to do this. 
" Future studies should include greater numbers of participants and collect better information on exposure,duration of symptoms before diagnosis, duration of symptoms before the intervention and report more fully on asthma 
symptoms, FEV1 and NSBH before, during and after the intervention. Studies are needed to fully evaluate the effect of reduction of exposure, through either personal protective equipment or education of workers after exposure is minimised, as far as reasonably achievable. Given the uncertainty of the effect of reduction of exposure and the beneficial effects of continued employment on health, these studies should randomise participants to reduction of exposure or removal from exposure" 

Using the Bradford Hill Criteria for casation from epidemiological studies the data stacks up strongly. The strength of the asssociation between exposure removal and reduction is high, it is biologically plausable, repeated in many different populations, has "dose-response" (earlier removal better and exposure reduction worse). It has temporal plausability.

References

	de Groene GJ, Pal TM, Beach J, Tarlo SM, Spreeuwers D, Frings-Dresen MH, Mattioli S, Verbeek JH, Workplace interventions for treatment of occupational asthma, Cochrane Database of Systematic Reviews, 2011;5:1-93,

Comments