Controversies in epidemiology of occupational asthma

Abstract

high-risk workplaces, medicolegal statistics and sentinel programmes indicate that y10% of adult-onset asthma is attributable to the workplace. The strategy to identify cases through questionnaires and tools that address functional, immunological and physiopathological issues needs to be improved.Although few in number and limited to a handful of workplaces, cohort studies found that the risk of developing occupational asthma is determined less by individual susceptibility (e.g. atopy, tobacco smoking, human leukocyte antigen phenotype) and more by the level of exposure to its causes; in general, the higher the exposure, the greater the risk, and, by implication, lowering the level of exposure reduces the incidence of disease.Occupational asthma can be used as a satisfactory model for the development of adult-onset asthma. There is a great need to develop intervention strategies through adequate surveillance programmes in high-risk workplaces. Eur Respir J 2003; 22: 551-559. Epidemiology of occupational asthma: general considerations on various study designs and methodological approachesEpidemiology is the study of the distribution, determinants and outcome of disease. In this article, the authors will describe recently acquired knowledge of the epidemiology of occupational asthma, as well as current areas of controversy.BECKLAKE et al.[1] have discussed the features, strengths and weaknesses of several designs used in epidemiological studies. These designs include the randomised control trial, the prospective cohort, the case-referent study, the crosssectional (prevalence) study and the case series. Which design to use in any particular situation is a matter of judgment, determined by a number of factors that may include resources, cost, collaboration of employers and employees, and the question under study. So far, primarily for practical convenience, most epidemiological studies of occupational asthma have been cross-sectional in type. As discussed in several reviews [1,2], this type of study, primarily in the case of occupational asthma (OA), suffers from survivor bias, whose magnitude can be difficult to quantify. Randomised control trials are usually not feasible and are probably unethical in workplace studies, but quasi-experimental studies can provide results of high internal and external validity. Prospective cohort studies are more expensive than cross-sectional studies but are more powerful and less likely to be affected by selection or survivor biases; in particular, it is often possible to track the participants who leave the cohort and determine the possible effect of attrition on the estimates of both the frequency of OA and exposure/effect relationships [3]. This type of study has recently been successfully applied in cohorts of young apprentices [4][5][6][7][8][9][10]. Some case-referent studies have been carried out in the field of OA [11,12]. These studies are valuable in identifying and quantifying risk factors. Finally, there are many case series that mainly describe clinical cases (often si...

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“…The prevalence of OA could therefore vary according to the diagnostic criteria of OA used. That is why a standardization of the investigating methods, not so much for the definition of OA as for the diagnostic tools used, is recommended in order to allow a comparison of results (Gautrin et al, 2003). This prevalence of OA as linked to 7.7% polyethylene in our study is higher than OA prevalence with 5.4% isocyanates observed in Algeria (Tibiche et al, 2014).…”

Occupational diseases among farmers in Poland

“…In the United Kingdom (UK), it is assumed that the underestimation value equals 1/3 of new cases [13]. The occupational fraction of the overall incidence of asthma among adults is estimated at 10-15% [14,15], while in the developed and rapidly developing countries those fractions are estimated at 13-14% and in the poor countries the corresponding value is 6% [16]. In Sweden, the fraction of occupational asthma among men is estimated at 29%, and among women at 17% [17].…”

Adjuvant effects of gaseous formaldehyde on the hyper-responsiveness and inflammation in a mouse asthma model immunized by ovalbumin

“…Recent epidemiological studies have been conducted for investigating the interrelationship between FA exposure and asthma (Franklin et al, 2000;Youk et al, 2001;Rumchev et al, 2002;Gautrin et al, 2003;Vandenplas et al, 2004;Casset et al, 2006;Mi et al, 2006;Syamlal et al, 2009). Whether FA causes asthma is still under debate; there are only a few reports on FA and respiratory sensitization (Salthammer et al, 2010).…”