Epidemiology of Tuberculosis in Circumpolar Regions: A First Glance
The International Circumpolar Surveillance Tuberculosis Working Group (ICS-TB) initiated a review of tuberculosis (TB) notifications in order to describe the epidemiology of TB in circumpolar regions. The objective was to compare TB incidence rates, assess disease trends, and measure levels of drug resistance and treatment outcomes across circumpolar regions.
METHODS:
Formal agreements between the Public Health Agency of Canada, custodian of the data, and nine ICS-TB jurisdictions [Canada (Northwest Territories, Nunavik, Nunavut, Yukon), Greenland, Norway, Sweden, Russian Federation (Arkhangelsk), United States (Alaska)] were signed. A common case definition and core data elements to be collected were established.
All active TB cases reported from 2006 to 2012 that met the case definition were analysed. Crude incidence rates and mean ages were calculated. Proportions of cases that were male, sputum smear positive pulmonary, multidrug resistant and had completed treatment (uptake ≥ 80% doses) were calculated.
RESULTS:
From 2006 to 2012, the jurisdictions reported overall TB disease incidence rates ranging from 6.3 to 219.1 cases per 100,000 population. The proportion of male cases ranged from 52.4% to 80.4%. Mean age ranged from 23.4 to 47.6 years. Smear positive pulmonary cases represented 29.1% of all cases (range 16.9%-51.7%). Five jurisdictions reported multidrug resistant cases comprising 0.2% to 18.9% of all TB cases in the affected jurisdictions. From 2006 to 2011, treatment was completed for a mean of 74.3% cases in the ICS-TB jurisdictions (range: 68.2%-96.4% across jurisdictions).
CONCLUSIONS:
This analysis shows that TB is a serious public health issue in many circumpolar regions and that drug resistance and treatment completion may be a challenge for some of the northern jurisdictions. International collaboration to examine tuberculosis trends in the north through knowledge sharing and standardised epidemiological practice may form a major step towards tuberculosis prevention and control in circumpolar regions.