Smoking,BCG and Employment and the Risk of Tuberculosis Infection in HIV-Infected Persons in South Africa |
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| Authors: | Tolu Oni Hannah P Gideon Nonzwakazi Bangani Relebohile Tsekela Ronnett Seldon Kathryn Wood Katalin A Wilkinson Rene T Goliath Tom H M Ottenhoff Robert J Wilkinson |
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| Institution: | 1. Clinical Infectious Disease Research Initiative, Institute of Infectious Diseases and Molecular Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa.; 2. Division of Medicine, Imperial College London, London, United Kingdom.; 3. Medical Research Council, National Institute for Medical Research, London, United Kingdom.; 4. Leiden University Medical Centre, Leiden, The Netherlands.; Hopital Raymond Poincare - Universite Versailles St. Quentin, France, |
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| Abstract: | BackgroundThe increased susceptibility to latent tuberculosis infection (LTBI) of HIV-1-infected persons represents a challenge in TB epidemic control. However few studies have evaluated LTBI predictors in a generalized HIV/TB epidemic setting.MethodsThe study recruited 335 HIV-infected participants from Khayelitsha, Cape Town between February 2008 and November 2010. Tuberculin skin tests and interferon-gamma release assays were performed on all participants and active TB excluded using a symptom screen, TB microscopy and culture.ResultsLTBI prevalence was 52.7% and 61.2% (TST and IGRA respectively). Being a recent TB contact (OR 2.07; 95% C.I. 1.15–3.69) was associated with TST positivity. Participants with a CD4>200 had a two-fold higher risk of IGRA positivity compared to those with CD4 counts <200 (OR 2.07; 95% C.I. 0.99–4.34). There was also a 19% increase in IGRA positivity risk for every additional year of schooling and a strong association between years of schooling and employment (p = 0.0004). A decreased risk of IGRA positivity was observed in persons with a BCG scar (OR 0.46; 95% C.I. 0.31–0.69) and in smokers (OR 0.47; 95% C.I. 0.23–0.96).ConclusionWe report the novel findings of a decreased risk of IGRA positivity in HIV-infected smokers possibly due to decreased interferon production, and in the persons with a BCG scar suggesting a protective role for BCG in this population. We also found an increased risk of TST positivity in employed persons, possibly due to ongoing transmission in public modes of transport. |
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