To get insight in the true burden of asbestosis in the population it’s not enough to rely on a single source. Triangulation of workers’ compensation, hospitalisation and outpatient databases records is necessary to get a better picture.

Population-based asbestosis surveillance in British Columbia
W Q Gan, P A Demers, C B McLeod M Koehoorn
Occupational and Environmental Medicine 2009;66:766-771 

Objectives: To investigate the use of multiple health data sources for population-based asbestosis surveillance in British Columbia, Canada.

Methods: Provincial health insurance registration records, workers’ compensation records, hospitalisation records, and outpatient medical service records were linked using individual-specific study identifiers. The study population was restricted to individuals >=15 years of age living in the province during 1992–2004.

Results: 1170 new asbestosis cases were identified from 1992 to 2004 for an overall incidence rate of 2.82 (men: 5.48, women: 0.23) per 100 000 population; 96% of cases were male and average (SD) age was 69 (10) years. Although the annual number of new cases increased by 30% during the surveillance period (β = 2.36, p = 0.019), the observed increase in annual incidence rates was not significant (β = 0.02, p = 0.398).

Workers’ compensation, hospitalisation and outpatient databases identified 23%, 48% and 50% of the total new cases, respectively. Of the new cases, 82% were identified through single data sources, 10% were only recorded in the workers’ compensation records, and 36% only in each of the hospitalisation and outpatient records. 84% of hospitalisation cases and 83% of outpatient cases were not included in the workers’ compensation records. The three data sources showed different temporal trends in the annual number of new cases and annual incidence rates.

Conclusions: Single data sources were not sufficient to identify all new cases, thus leading to serious underestimations of the true burden of asbestosis. Integrating multiple health data sources could provide a more complete picture in population-based surveillance of asbestosis and other occupational diseases.