The Effect of Diabetes and Prediabetes on Mycobacterium tuberculosis Transmission to Close Contacts

Abstract

Background It is unknown whether dysglycemia is associated with M. tuberculosis transmission. Methods We assessed epidemiological and clinical characteristics of patients with culture-confirmed pulmonary TB and their close contacts, enrolled in a multicenter prospective cohort in Brazil. Contacts were investigated at baseline and 6 months after enrollment. QuantiFERON positivity at baseline and conversion (from negative to positive at month 6) were compared between subgroups of contacts according to glycemic status of persons with tuberculosis (PWTB) as diabetes mellitus (DM) or prediabetes. Multivariable mixed-effects logistic regression models were performed to test independent associations with baseline QuantiFERON-positive and QuantiFERON-conversion. Results There were 592 PWTB (153 DM, 141 prediabetes, 211 normoglycemic) and 1784 contacts, of whom 658 were QuantiFERON-positive at baseline and 106 converters. Multivariable analyses demonstrated that TB-prediabetes cases, acid-fast bacilli-positive, pulmonary cavities, and living with someone who smoked, were independently associated with QuantiFERON-positive in contacts at baseline. DM, persistent cough, AFB-positive and pulmonary cavities in TB source cases were associated with QuantiFERON-conversion. Conclusion Contacts of persons with pulmonary TB and dysglycemia were at increased risk of being QuantiFERON-positive at baseline or month 6. Increased focus on such close contacts could improve TB control.

Respiratory Tract Infections in Diabetes – Lessons From Tuberculosis and Influenza to Guide Understanding of COVID-19 Severity

“…In-vivo Mtb infections in diabetic mouse models display heightened lung inflammation and bacillary burden ( 50 , 51 ). This correlates with clinical observations of increased lesions, cavities and increased transmissibility of TB in T2D patients ( 52 , 53 ). Although the antigen-presenting ability of innate cells was not affected by hyperglycemia ( 54 ), altered cytokine production can affect the nature of the subsequent T-cell response contributing to poorer bacterial containment ( 48 ).…”

Possible sex difference in latent tuberculosis infection risk among close tuberculosis contacts

“…Regional Prospective Observational Research for TB in Brazil (RePORT-Brazil) is a prospective observational cohort study of culture-confirmed pulmonary TB cases and their close contacts (Arriaga et al, 2021). There were five sites across three high TB-burden regions in Brazil: three in the southeast (Rio de Janeiro -Rio de Janeiro), one in the northeast (Salvador -Bahia), and one in the north (Manaus -Amazonas).…”

“…Brazil is a highly diverse upper-middle income country with large gaps in income equality and decreasing, yet still substantial TB burden. Our well-characterized multi-center cohort closely represents the TB patient population in Brazil and is well positioned to address this question (Arriaga et al, 2021). Based on preliminary data within our cohort (Souza et al, 2021;Arriaga et al, 2021), we hypothesized that female close contacts would have higher rates of IGRA positivity than men, even after adjusting for potentially confounding factors.…”

Diabetes-Associated Susceptibility to Tuberculosis: Contribution of Hyperglycemia vs. Dyslipidemia

“…Higher smear grades in patients with TB-T2D co-morbidity are indicative of higher lung mycobacterial burdens, suggesting that TB patients with T2D are more infectious than TB patients without co-morbidities [23]. A recent study from Brazil confirmed that TB patients with any form of dysglycemia (T2D or pre-diabetes) are more likely to transmit Mtb in a household contact setting [24].…”