Diabetes-Associated Susceptibility to Tuberculosis [TB0120]

Diabetes and TB Risk:
It is unclear whether diabetes increases the risk of active TB more significantly in overweight/obese individuals than in those who are underweight or have low BMI, especially in Asian populations where T2D develops at lower BMI levels.
The distinction between newly diagnosed T2D requiring clinical management and transient stress hyperglycemia during TB treatment is critical.

TB and Diabetes Development:
While a history of TB is associated with a higher risk of developing T2D, the causal relationship remains inconclusive.

Cholesterol and TB:
Elevated cholesterol may have a protective role against TB. A large South Korean study found that low total cholesterol levels were associated with a higher TB risk, though this relationship weakened in individuals with T2D, obesity, or statin use.
Active TB patients typically have lower cholesterol levels due to disease-related wasting. However, higher cholesterol among TB patients correlates with reduced disease severity, with HDL and LDL inversely associated with the radiological extent of TB.

Lipid Profiles and TB Treatment Outcomes:
Elevated triglycerides are linked to poorer TB treatment outcomes. Lower cholesteryl ester concentrations are associated with treatment failure, with specific esters predictive of outcomes.
Cholesterol plays a role in TB pathogenesis, as it aids macrophage phagocytosis of Mycobacterium tuberculosis (Mtb). Elevated total cholesterol can increase oxidized cholesterol forms, enhancing phagocytosis and reducing Mtb growth in monocytes.

Source: Ngo, M.D.; Bartlett, S.; Ronacher, K. Diabetes-Associated Susceptibility to Tuberculosis: Contribution of Hyperglycemia vs. Dyslipidemia. Microorganisms 2021, 9, 2282. https://doi.org/10.3390/ microorganisms9112282