Marked disparity in the epidemiology of tuberculosis among Aboriginal peoples on the Canadian prairies: the challenges and opportunities.

BACKGROUND

While it is established that Aboriginal peoples in the prairie provinces of Canada are disproportionately affected by tuberculosis (TB), little is known about the epidemiology of TB either within or across provincial borders.

METHODS

Provincial reporting systems for TB, Statistics Canada censuses and population estimates of Registered Indians provided by Aboriginal Affairs and Northern Development Canada were used to estimate the overall (2004 to 2008) and pulmonary (2007 to 2008) TB rates in the prairie provinces. The place of residence at diagnosis of pulmonary TB cases in 2007 to 2008 was also documented.

RESULTS

The age- and sex-adjusted incidence of TB in Registered Indians was 52.6 per 100,000 person-years, 38 times higher than in Canadian-born 'others'. Incidence rates in Registered Indians were highest in Manitoba and lowest in Alberta. In Alberta and Saskatchewan, on-reserve rates were more than twice that of off-reserve rates. Rates in the Métis and Registered Indians were similar in Saskatchewan (50.0 and 52.2 per 100,000 person-years, respectively). In 2007 to 2008, approximately 90% of Canadian-born pulmonary TB cases in the prairie provinces were Aboriginal. Outside of one metropolitan area (Winnipeg, Manitoba), most Registered Indian and Métis pulmonary TB cases were concentrated in a relatively small number of communities north of the 53rd parallel. Rates of pulmonary TB in 11 of these communities were >300 per 100,000 person-years. In Manitoba, 49% of off-reserve Registered Indian pulmonary cases were linked to high-incidence reserve communities.

INTERPRETATION

The epidemiology of TB among Aboriginal peoples on the Canadian prairies is markedly disparate. Pulmonary TB is highly focal, which is both a concern and an opportunity.