Population impact of factors associated with prevalent pulmonary tuberculosis in Tanzania

Abstract

SETTING: Tanzania has an estimated tuberculosis (TB) prevalence of 295 per 100 000 adult population. There is currently no nationally representative information on factors associated with TB in Tanzania. OBJECTIVE: To determine the demographic and clinical factors associated with bacteriologically confirmed TB in the adult general population of Tanzania. DESIGN: A case-control study nested in a nationally representative TB prevalence survey. All patients with bacteriologically confirmed pulmonary TB (PTB) constituted cases and a representative sample of people without bacteriologically confirmed PTB constituted controls. We calculated adjusted odds ratios (aORs) to identify factors associated with TB. RESULTS: Age groups 25–34 years (aOR 3.7, 95%CI 1.5–8.8) and 55–64 years (aOR 2.5, 95%CI 1.1–5.5), male sex (aOR 1.6, 95%CI 1.1–2.3) and low body mass index (BMI) (aOR 1.7, 95%CI 1.1–2.8) were significantly associated with TB. Association with human immunodeficiency virus (HIV) and diabetes mellitus (DM) was not statistically significant. The population attributable fraction (PAF) was 2% (95%CI −2 to 5) for DM and 3% (95%CI −2 to 8) for HIV. CONCLUSION: Being in an older age group, being male and having a low BMI were associated with bacteriologically confirmed PTB. On the population level, classic risk factors for TB have no major effect on prevalent TB from which future transmission may occur.