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30-03-2010 | Respiratory | Article

Occupational exposure accounts for significant proportion of severe asthma attacks


Free abstract

MedWire News: Around one in seven severe asthma attacks among people of working age are caused by occupational exposure to substances and gases, study results suggest.

“Work-related asthma includes both occupational asthma (OA) caused by work and work-exacerbated asthma (WEA) in which existing asthma is made worse by work,” explain P Henneberger (Centers for Disease Control and Prevention, Morgantown, West Virginia, USA) and team.

They add: “WEA has generally received less attention than OA, and a better understanding of the causes of WEA is needed to plan preventive interventions.”

To investigate the proportion of severe asthma exacerbations caused by occupational exposure, and to identify occupational risk factors for such events, the researchers studied data on 966 working adults with asthma, aged 20–44 years, who participated in the European Community Respiratory Health Survey.

Exacerbations were defined as severe if participants needed treatment for breathing problems in a hospital emergency room, had an overnight stay in hospital due to breathing problems, needed emergency treatment by a general practitioner for breathing problems at home, or used oral steroids to control symptoms.

Occupational exposure to various substances was assessed using a general-population job-exposure matrix.

In total, 217 (22%) participants reported that they had experienced chest tightness or wheezing due to a work-related asthma exacerbation in the previous 12 months. Of these, 74 (7.7%) reported having at least one severe exacerbation in the previous 12 months.

After accounting for potential confounding factors, such as smoking status and gender, the researchers found that low and high levels of exposure to biological dust were associated with a respective 1.7- and 3.6-fold increased relative risk (RR) for severe asthma exacerbations among the participants.

Exposure to high levels of mineral dust and high levels of gas and fumes were also associated with a significantly increased risk for severe exacerbations, at RRs of 1.8 and 2.5, respectively.

High risk occupations included baking, driving, and nursing, the researchers note in the European Respiratory Journal.

Based on the findings, they calculated that the population attributable risk percentage for severe exacerbations due to occupational exposure among employed adults with current asthma was 14.7%.

Henneberger and team conclude: “Occupational exposure to dust, gas, or fumes makes an important contribution to severe exacerbation of current asthma among working adults.”

They add that further efforts are needed to limit or prevent occupational exposure to substances known to increase the risk for severe asthma exacerbations.

MedWire ( is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010

By Mark Cowen

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