Prevalence of occupational asthma in 23-25 year olds in Brazil

The paper quotes a prevalence of 2.7% occupational asthma and 1.5% work agravated asthma. Diagnostic criteria are restrictive, as all subjects had to have a Pc20 methacholine <=4 mg/ml after a 2 minute inhalation (this is likely to exclude around 50% of those diagnosed without a requirement for non-specific hyperresponsiveness) and all subjects deteriorating at work with any pre-existing asthma were classed as work agravated asthma (most would include those with a latent interval between exposure and work-relatedness and exposure to a known sensiting agent as occupational asthma).
Those studied are a birth cohort born in a sugar cane producing area of Brazil (Ribeirao Preto) and studying 1922/2063 of the intended sample. Risk factors for occupational asthma were a poor level of education and particularly exposure to chemical products or paints; OR 4.71(and to a lesser extent dust, vapour, humidity or gasses; OR 2.27).
Surveillance schemes identify most workers with occupational asthma at a much older age than in this study; the current study is likely to substantially underestimate the total ammount of adult asthma attributable to work.
This is a good study

References

	Caldeira RD, Bettiol H, Barbieri MA, Terra-Filho J , Garcia CA , Vianna EO, Prevalence and risk factors for work related asthma in young adults, Occup Environ Med, 2006;63:694-699,

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