Alcohol consumption as a risk factor for tuberculosis: meta-analyses and burden of disease

Tuberculosis, social determinants and co-morbidities (including HIV)

The risk of exposure, progression to active tuberculosis (TB) and then to cure is a process affected by several risk factors. Along with well known risk factors such as human immunodeficiency virus (HIV), use of immunosuppressive drugs and being of young age, emerging risk factors such socio-economic and behavioral aspects play a significant role in increasing the susceptibility to infection, and unsuccessful treatment outcomes. This paper summarizes the effects of these socio-economic determinants and co-morbidities (including HIV) on TB infection and disease.

Diagnostic performances of the Xpert MTB/RIF in Brazil

BACKGROUND AND OBJECTIVES

As for all tests, the diagnostic performances of Xpert MTB/RIF might be different in settings with different tuberculosis prevalence. Aim of the study is to evaluate the performances of Xpert MTB/RIF to diagnose tuberculosis in Brazil, where 407 culture-confirmed tuberculosis patients were retrospectively enrolled in Rio Grande do Sul, between 2015 and 2016.

METHODS

Sensitivity, specificity, positive and negative predictive values of the test were calculated and a logistic regression analysis was performed to assess the role played by explanatory variables in the occurrence of true positive and negative diagnostic results.

RESULTS

Sensitivity of Xpert MTB/RIF was 100.0%, specificity 92.8%; positive and negative predictive values were 71.4% and 100.0%, respectively. In the HIV- infected sub-group specificity was 59.3%. In the multivariate logistic regression analysis, true positivity was associated with increasing age (1.0; p-value: 0.02) while true positivity and negativity were negatively associated with alcohol abuse.

CONCLUSIONS

Xpert is sensitive and specific in the Brasilian settings.

Alcohol drinking and cigarette smoking in relation to risk of active tuberculosis: prospective cohort study

INTRODUCTION

Heavy alcohol consumption increases the risk of active tuberculosis (TB). However, the relation between lower levels of alcohol intake and TB risk remains unclear. We aimed to evaluate the association between alcohol intake and risk of active TB and assess whether the associations were modified by smoking status, which is another risk factor for active TB.

METHODS

The Singapore Chinese Health Study is a prospective cohort of 63 257 adults aged 45-74 years recruited from 1993 to 1998. Information on alcohol intake and smoking history was collected at recruitment. Active TB cases were identified via linkage with National TB Notification Registry.

RESULTS

During a mean follow-up of 16.8 years, 1249 incident cases of active TB were identified. Among non-smokers, compared with total abstinence, participants who had monthly to weekly intake of alcohol had reduced TB risk (HR 0.70, 95% CI 0.55 to 0.89), but this reduction in risk with low-dose drinking was not observed among current smokers (HR 0.96, 95% CI 0.77 to 1.18; p for interaction=0.02). Comparatively, drinking 2+ drinks daily was associated with increased TB risk among current smokers (HR 1.51, 95% CI 1.11 to 2.05). This increased risk was not observed among non-smokers (HR 0.93, 95% CI 0.49 to 1.77) and the interaction between alcohol intake and smoking status was of borderline significance (p for interaction=0.08). In joint effect, compared with those who neither smoked nor drank, the risk of active TB increased from 1.82 (95% CI 1.57 to 2.10) in current smokers who were non-drinkers to 3.16 (95% CI 2.35 to 4.24) in current smokers who also drank 2+ drinks daily.

CONCLUSION

While low intake of alcohol may protect against active TB among non-smokers, drinking 2+ drinks daily could act synergistically with smoking to increase the risk of active TB in current smokers.