The occupational risk of tuberculosis in a low-prevalence population.

Abstract

The incidence of tuberculosis (TB) infection in low-prevalence countries has been declining. Estimates of the risk of occupational TB in these countries are contradictory. To evaluate the risk of occupational TB in a low-prevalence population using a comprehensive database. All compensation claims in British Columbia (BC), Canada, reporting workplace TB exposure for the years 1999-2008 were reviewed. Cases with TB infection were identified for all occupational groups with five or more claims in the decade and analysis provided estimates of incidence rates of active TB and relative risks of latent TB (LTB) infections. There were 70 occupational groups making 639 claims including 100 with LTB and eight with active TB. Only 18 occupations had five or more claims. Four occupational groups had a significantly increased relative risk of infection compared with all other occupational groups. These were employment counsellors, registered nurses, x-ray technicians and home support workers. Active TB infections were relatively rare compared with the general population (1-4 compared with 7-10/100000 person-years, respectively). Few occupational groups were at risk of TB exposure at work on a regular basis. Only a handful had an apparent increased risk of contracting TB and these should be the focus of prevention efforts. Work-related active TB infections are rare hence the burden of occupational TB disease is low in BC.