Diabetes is a risk factor for tuberculosis in the Inuit population of Greenland

Abstract

To the Editors: Diabetes is a known risk factor for tuberculosis (TB), and studies across populations and geographic regions suggest substantial increased risks of developing TB ranging from 1.16 to 7.83 with co-existing diabetes [1]. It is suggested that the risk is due to latent TB infections being activated by the hyperglycemia associated with diabetes. The evolving epidemiology of concurrent diabetes and TB in settings where both diseases are frequent is therefore looked upon with special concern. The prevalence of diabetes among the Greenland Inuit is high (10%) and increasing [2]. Meanwhile, the TB incidence remains high with an estimated 180 cases per 100,000 suggesting ongoing TB transmission [3]. The aim of this study was to quantify the effect of diabetes on TB development among the Greenland Inuit. We conducted a retrospective cohort study. Study participants comprised ethnic Inuit who participated in two previously conducted cross-sectional studies where diabetes status were assessed; Inuit Health in Transition Study (IHIT) [4] and the Greenland Population Study (B99) [2]. All study participants in IHIT and B99 were randomly selected from the Civil Registration System (CRS) in order to represent the entire Greenlandic population. The CRS provides all citizens of Greenland with a unique identification number at birth, facilitating tracing of persons through all public registries. The CRS identifier enabled follow-up of study participants in the National TB register. The study was approved by the Ethics Review of Greenland. Participants not previously diagnosed with diabetes (98%) underwent a standard oral glucose tolerance test (OGTT). Participants were categorised with diabetes if previously diagnosed with diabetes or if fasting and 2-h blood glucose levels were ≥7 mmol·L−1 and ≥11.1 mmol·L−1, respectively. …