Characteristics of tuberculosis in Aboriginal populations : is there a difference in rates by residence (on or off reserve)?

Abstract

Tuberculosis is a major public health problem in Aboriginal populations. Studies are lacking to evaluate incidence of tuberculosis across residence status. The incidence of tuberculosis in Saskatchewan’s Aboriginal population was investigated to determine whether differences existed between off- and on-reserve groups. A retrospective cohort study was performed, using data from the Saskatchewan Tuberculosis Control Program database of on and off reserve residents diagnosed with pulmonary tuberculosis between January 1, 1986, and December 31, 2005. Age, sex and residence-specific incidence rates were calculated with the use of Census populations for 1986, 1991, 1996 and 2001. Multivariate analysis using poisson regression was completed.There were 1750 cases during the study period; 710 occurred off reserve and 1040 on reserve. 1337 cases were diagnosed in Registered Aboriginals, with the remaining 413 in the non-registered population. The mean age of Aboriginal cases on reserve was 12.92 and 19.98 for off reserve cases. Females were more likely to have tuberculosis on reserve, while males were more likely off reserve. Overall, TB rates both on and off reserve decreased over the study period. The on reserve population maintains greater rates of tuberculosis compared to their off reserve counterparts, after adjustment for age.Although there is a natural history to infectious disease epidemics such as tuberculosis, it should be a higher priority of government policies and services to further decrease rates. The collection of more accurate population statistics would allow for more in-depth surveillance of TB in Saskatchewan and would contribute to knowledge about how and where to best allocate future resources.