Convergence of a diabetes mellitus, protein energy malnutrition, and TB epidemic: the neglected elderly population

Abstract

BackgroundOn a global scale, nearly two billion persons are infected with Mycobacterium tuberculosis. From this vast reservoir of latent tuberculosis (TB) infection, a substantial number will develop active TB during their lifetime, with some being able to transmit TB or Multi-drug- resistant (MDR) TB to others. There is clinical evidence pointing to a higher prevalence of infectious diseases including TB among individuals with Diabetes Mellitus (DM). Furthermore, ageing and diabetes mellitus may further aggravate protein-energy malnutrition (PEM), which in turn impairs T-lymphocyte mediated immunologic defenses, thereby increasing the risk of developing active TB and compromising TB treatment. This article aims to a) highlight synergistic mechanisms associated with immunosenescence, DM and PEM in relation to the development of active TB and b) identify nutritional, clinical and epidemiological research gaps.MethodsTo explore the synergistic relationship between ageing, DM, tuberculosis and PEM, a comprehensive review was undertaken. The MEDLINE and the Google Scholar databases were searched for articles published from 1990 to March 2015, using different MESH keywords in various combinations.ResultsAgeing and DM act synergistically to reduce levels of interferon gamma (IFN- γ), thereby increasing susceptibility to TB, for which cell mediated immunity (CMI) plays an instrumental role. These processes can set in motion a vicious nutritional cycle which can predispose to PEM, further impairing the CMI and consequently limiting host defenses. This ultimately transforms the latent TB infection into active disease. A clinical diagnostic algorithm and clinical guidelines need to be established for this population.ConclusionGiven the increase in ageing population with DM and PEM, especially in resource-poor settings, these synergistic tripartite interactions must be examined if a burgeoning TB epidemic is to be averted. Implementation of a comprehensive, all-encompassing approach to curb transmission is clearly indicated. To this end, clinical, nutritional and epidemiological research gaps must be addressed without a delay.

Drivers of Tuberculosis Transmission

“…Third, host factors may increase an individual’s risk of progression to active pulmonary disease after infection. Host-related determinants of disease risk include HIV infection [ 19 ], diabetes [ 20 ], smoking [ 21 ], excess alcohol use [ 22 ], and malnutrition [ 23 ]. The degree of infectiousness of the inoculum (ie, dose) also may influence the likelihood of disease [ 24 ].…”

Gridlock from Diagnosis to Treatment of Multidrug Resistant Tuberculosis (MDR-TB) in Tanzania: Patients’ Perspectives from the Focus Group Discussion

“…Emergence of multidrug-resistant tuberculosis (MDR-TB) in settings with high burden of human immunodeficiency virus (HIV), diabetes mellitus (DM), and malnutrition poses an ominous challenge and threatens to dismantle the previous achievements in TB control [1]. MDR-TB is a laboratory diagnosis that requires not only identifications of Mycobacterium tuberculosis (MTB) but also determining resistance of at least rifampicin and isoniazid [2].…”

Diabetes mellitus among adults with tuberculosis in the USA, 2010–2017

“…8 In older persons, diabetes and the ageing process itself synergistically reduce levels of interferon gamma, impairing cellmediated immunity and helping to activate progression of long-standing LTBI. 16 Both TB disease and LTBI in the USA occur primarily among non-US-born persons. 8 17 18 6 BMJ Open Diab Res Care 2020;8:e001275.…”