The relationship between diabetes and tuberculosis in Saskatchewan - Comparison of registered Indians and other Saskatchewan people

Background: Saskatchewan Aboriginal people are experiencing epidemics of both type 2 diabetes (T2DM) and tuberculosis (TB). The purpose of this study was to determine if a relationship exists between diabetes and TB in Saskatchewan and to establish whether there is a difference in the degree of any association between Aboriginal and non-Aboriginal people. Methods: Utilizing Saskatchewan Health databases, TB incidence (cases identified from 1986-2001) was compared between four subpopulations identified from 1991-1995: Registered Indians (RI) with and without diabetes, and other Saskatchewan people (OSKP) with and without diabetes. Results: Diabetic women aged 20-59 years had higher average annual incidence rates of TB than non-diabetic women, but with in-population rate ratios of TB in diabetic versus non-diabetic women were only significant in those aged 50-59 (2.7 [CI 1.28, 5.721 in RI and 3.9 [Cl 1.58, 9.671 in OSKP). No other within-population diabetic subgroup had significantly higher rates of TB. The only male diabetic group that had a higher rate of TB were RI plus OSKP men aged 50-59 years. overall, diabetes preceded TB in 87/111 individuals with both diseases (p < 0.0001). Conclusions: Our results suggest that T2DM is a predictor for TB in Saskatchewan women aged 20-59 but particularly in RI and OSKP women aged 50-59 years. This has implications for TB screening and prevention initiatives.