ISSN: 2161-1068
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Letter to Editor - (2017) Volume 7, Issue 2
Dear Editor,
Tuberculosis (TB) is one of the leading causes of death worldwide and, although great efforts have already been made, the way to defeat this disease is still long [1]. The burden of TB is higher in Sub-Saharan Africa and low income countries where, another increasing plague, the diabetes mellitus (DM) is affecting more and more people. The rapid increase of DM and its coexistence with TB and HIV is a clear example of overlap and interaction between communicable and noncommunicable diseases requiring a multidisciplinary and integrated approach [2]. The association between TB and DM, in particular in low and medium income countries, has been showed to cause a mutual worsening of the natural history of both diseases. Although the pathophysiological mechanism is still unclear, it has been observed that each disease may adversely affect the outcomes of the other, in terms of delayed diagnosis and healing, severity of symptoms, mortality [2]. However, to date, contrasting data are available regarding TB prevalence in diabetes and vice versa and, recent findings suggest a high burden of diabetes among TB patients but low prevalence of TB among DM patients [3]. Apparently, this is a contrast that could be partially explained by social determinants of health (SDH). In fact, growing evidence suggests that the lack of efficacy in containing TB and the presence of multi drug resistance (MDR), is due to many factors including SDH [4]. SDH are defined as conditions in which people are born, grow, live, work and get old having an immediate impact on health and are greatly influenced by the distribution of money, power and resources [5]. In particular, low education, low income and alcohol abuse are significant predictors of therapy failure and MDR in people with TB.
On one hand, in fact, the high prevalence of DM in TB patients is a consequence of increased susceptibility. In fact, malnutrition and physical inactivity lead patients with TB to stimulate adrenaline, glucagon and cortisol at the same time, thus increasing glucose levels [6]. Moreover, the higher incidence of chronic calcified pancreatitis in patients with TB and vitamin A, C and D deficiencies might also explain the impaired glucose tolerance and increased risk of DM [7].
On the other hand, although diabetes seems to be a “risk factor” for TB, affecting innate as well as adaptive immune responses [8], the presence of diabetes in many cases, especially in developing countries, is to mean a well-being state and, thus, good SDH.
Regardless of the pathophysiologic basis, especially in developing countries, both diseases are increasing and represent a huge health, social and economic burden. For this reason, it is mandatory to strengthen the efforts in two main aspects: clinic and scientific.
In fact, on one side, it is necessary to develop integrated and multidisciplinary approaches in order to improve the prevention, the screening and the management of dual diseases. Moreover, to achieve more effective results, it is also critical to perform early diagnosis, treatment and management of co-morbidities and, regarding latent TB, preventive therapy.
On the other side, the complexity of the association between TB and DM requires a great effort from the scientific community to clarify the many outstanding issues and to develop appropriate and adequate strategies of health policies in different settings.