World Tuberculosis Day was on the 24^th March  and this year’s focus of the Stop TB Partnership, a collective force of 1000 partners in more than 100 countries including the WHO, is to prevent the deaths of the 4000 people who lose their lives to Tuberculosis (TB) every day.

TB is an indiscriminate disease affecting people all over the world. Globally  a third of the world’s population is thought to be infected. According to the CDC year on year decreases mean that there were 3.4 cases per 100,000 people in the US in 2011, and the equivalent NICE statistic for the UK in 2008 was 14.1 per 100,000 people. However in Ethiopia, according to the World Health Organisation (WHO), the 2011 data shows an incidence of 250 cases per 100,000 people, a fifth of whom also have HIV. It was responsible for 29,000 deaths in 2010, ranking Ethiopia as seventh for TB burden in the world.

Diabetes has received increasing attention as a risk factor for TB. It weakens the immune system making it easier for people to succumb to infection by TB, increasing risk by two to three times. People with diabetes are also more likely to progress from latent to active TB. But what does this actually mean in countries such as Ethiopia where the incidence of TB is high?

A study published in the open access journal, Infectious Diseases of Poverty, looked at smear positive pulmonary TB (PTB) among diabetic patients at the Dessie referral hospital, in Northeast Ethiopia. Little has previously been explored about the prevalence and associated risk factors of PTB for those with diabetes in that area. In this study PTB occurred  more often among patients with diabetes at a rate of 6% compared to 0.4% of the general population – far higher than the global increased risk found by the WHO. Additional (independent) increased risk was found for patients with a history of TB, with history of contact with TB patients at home, or living in urban areas, as well as prolonged duration of their diabetes.

Discussing their work, the authors from Bahir Dar Regional Health Research Laboratory Center and University of Gondar, explain that active screening and treatment of PTB among patients with diabetes is especially relevant in TB-endemic countries, such as Ethiopia.

Both diabetes and TB are on the increase worldwide, bringing high death rates, high burden of care, and challenges associated with controlling both diseases at the same time. All of this makes additional knowledge about their interaction and implications for screening and treatment extremely valuable. This study shows that regional knowledge can be equally important is controlling the spread of TB and in identifying those at risk.

by Hilary Glover and Ruth King