- Asthma prevalence has increased worldwide and in Canada over the last three decades, and represents a substantial burden for individuals, families, and health care systems.
- Because asthma is so widespread and often difficult to attribute to specific occupational exposures, the condition presents a particular challenge to workers’ compensation boards.
- We used medical service plan billing files, hospitalization records, and WorkSafeBC compensation records to examine the cumulative prevalence and incidence of new cases of asthma in children and the working-age population.
- We then estimated the number of asthma cases that may be attributable to workplace exposures, and compared these results to the number of compensated claims.
- We found that in 2000, the ten-year cumulative prevalence of asthma among the working-age population of BC was 51 and 68 cases per 1,000 among males and females respectively.
- Of this population, 37 per cent of females and 34 per cent of males received physician or hospital treatment for their asthma in 2000—an overall rate of 26 per 1,000. The prevalence of active asthma increased slightly between 1996 and 2000, most notably among adult females.
- The cumulative prevalence of asthma among the pre-working-age population (ages 10 to 14) was 154 and 108 cases per 1,000 among males and females respectively. This large group of children who have, or have had, asthma indicates that a large percentage of young workers may enter the labour force with underlying sensitivities.
- The incidence of new cases of asthma among the working-age population was four and three cases per 1,000 among males and females respectively in 2000.
- The incidence of new cases of asthma remained relatively stable in the province between 1996 and 2000.
- Using a Population Attributable Risk (an estimate of the proportion of cases of a disease that could be avoided if all workplace exposures were eliminated) of 15 per cent, approximately 27,000 working-age British Columbians experienced work-related asthma in 2001 (nine cases per 1,000).
- Five-hundred-and-thirty occupational asthma claims were accepted by WorkSafeBC between 1991 and 2000—two per cent of estimated work-related asthma.
- Applying a 15 per cent Population Attributable Risk, approximately 9,000 working-age British Columbians were receiving treatment for active work-related asthma in 2000.
- Just over 100 occupational asthma claims were compensated in the same year—about one per cent of estimated work-related asthma.
- The difficulty of linking cases to workplace exposures may explain, at least in part, the gap between estimated asthma rates and compensation rates.