Occupational Asthma in Adults in Six Canadian Communities

180

111

There is accumulating evidence that the workplace environment contributes significantly to the general burden of asthma. The purpose of this review is to explore the respiratory health and socioeconomic consequences of work-related asthma by addressing a series of controversial issues: 1) what is the natural history of occupational asthma and in what ways does ongoing exposure to the causal agent impact clinical outcomes?; 2) how does the natural history of irritant-induced asthma differ in its health outcomes from immunologically-mediated occupational asthma?; 3) do working conditions have a significant impact on asthma regardless of the aetiology of the disease?; 4) what is the scope of work disability from work-related-asthma in social and economic terms?; 5) what is the clinician9s role in reducing the respiratory health consequences of work-related asthma? 6) to what extent do existing compensation and other social insurance schemes successfully address occupational asthma and workaggravated asthma? Eur Respir J 2003; 22: 689-697.

mentioning

confidence: 78%

Health and socioeconomic impact of work-related asthma

Vandenplas

Torén²,

Blanc³

2003

180

111

“…These surveys have been restricted to individual workplaces or to groups of individuals from the same occupation [24]. More recently, population-based studies have been undertaken to estimate the prevalence of OA [25][26][27]; in addition, data from population surveys have been analysed to derive such estimates [28]. These results are helpful in providing information about the size of the problem in high-risk workplaces, although they are potentially prone to survivor bias.…”

Section: Prevalence Of Occupational Asthmamentioning

confidence: 99%

“…symptoms of wheezing, cough, dyspnoea, chest tightness that resolve after some time away from work [18,29,30]; or 2) as one or the other of combinations that include work-related respiratory symptoms, specific immunological sensitisation [31], variation in serial peak-flow measurements [32][33][34] and increased nonspecific bronchial responsiveness [7]. As uncertainty persists in the ascertainment of OA in epidemiological studies, the terms "asthma-like," "possible OA" [25] and "probable OA" [7,25] have been used to describe the syndrome. An additional source of controversy in the ascertainment of OA is that it can be defined as new-onset asthma [22] or as workaggravated asthma [35].…”

Section: Prevalence Of Occupational Asthmamentioning

confidence: 99%

Controversies in epidemiology of occupational asthma

Gautrin¹,

Aj²,

Nordman³

et al. 2003

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...

“…A 2003 statement of the American Thoracic Society concluded that 15% of new-onset asthma among adults was due to occupation, but that there could be much more sickness and loss of productivity due to work-related exacerbation of existing asthma [2]. Six recent epidemiological studies conducted in five countries estimated the frequency of WEA, separate from cases of OA caused by work [3][4][5][6][7][8]. From these studies, the prevalence of WEA expressed as a percentage of working adults with asthma ranged from 14% to 24%, with a median of 19% [3,5,6,8].…”

mentioning

confidence: 99%

“…Past studies have started with asthma cases, evaluated these cases individually to determine WEA status, and then expressed the frequency of WEA as a percentage of asthma cases [3][4][5][6][7][8]. Unlike previous studies, the current investigation used a riskset approach in which ECRHS II participants with severe exacerbation of asthma were identified, and this outcome was modelled with covariates for occupational exposure to derive estimates of relative and attributable risk.…”

mentioning

confidence: 99%

The occupational contribution to severe exacerbation of asthma

Henneberger

Mirabelli²,

Kogevinas³

et al. 2010

The goal of this study was to identify occupational risk factors for severe exacerbation of asthma and estimate the extent to which occupation contributes to these events.The 966 participants were working adults with current asthma who participated in the follow-up phase of the European Community Respiratory Health Survey. Severe exacerbation of asthma was defined as self-reported unplanned care for asthma in the past 12 months. Occupations held in the same period were combined with a general population job-exposure matrix to assess occupational exposures.74 participants reported having had at least one severe exacerbation event, for a 1-yr cumulative incidence of 7.7%. From regression models that controlled for confounders, the relative risk (RR) was statistically significant for low (RR 1.7, 95% CI 1.1-2.6) and high (RR 3.6, 95% CI 2.2-5.8) biological dust exposure, high mineral dust exposure (RR 1.8, 95% CI 1.02-3.2), and high gas and fumes exposure (RR 2.5, 95% CI 1.2-5.5). The summary category of high dust, gas, or fumes exposure had RR 3.1 (95% CI 1.9-5.1). Based on this RR, the population attributable risk was 14.7% among workers with current asthma.These results suggest occupation contributes to approximately one in seven cases of severe exacerbation of asthma in a working population, and various agents play a role.