Abstract
Background: TB has been linked previously with environmental risk factors that are parallel with poverty, such as indoor air pollution, tobacco smoke, malnutrition, overcrowded living conditions, and excessive alcohol use. TB control strategies emphasise treatment solutions using drugs, vaccines, and increased access to health care. Although treatment is essential, longer-term strategies in TB epidemic control should start to address the risk factors for acquiring negative TB treatment outcomes, such as Initial-Loss-To-Follw-up, Not Evaluated, Died and Treatment failure.
Aim: The purpose of this study was to determine and describe environmental factors associated with Tuberculosis incidence and mortality in Tshwane district.
Methodology: The crude and adjusted odds ratios (OR) and their respective 95 percent confidence intervals (CI) were calculated using binary logistic regression. Adjustments were done specifically for: age, gender, marital status, occupation type, type of work, number in household, Tb treatment at time of survey, index patient, travel method, risky environment, other chronic illness, personal risk factors, current Tb treatment outcome, and patient category. The independent variables were all included in the model of comparison for cases and controls.
Results: 36 to 60 yr. olds Adjusted Odds Ratio (AOR 1.90, 95% CI 1.30 – 1.90), divorced (AOR 2.00, 95% CI 0.12 – 2.63) and diabetic participants (AOR 8.70 95% CI 4.00 – 19.00) had a significantly positive association with TB incidence. Other chronic diseases (AOR 2.00, 95% CI 2.00 – 2.20) significantly increased the odds of developing TB. Smokers were significantly (AOR 6.40, 95% CI 2.10- 19.63) likely to develop TB disease. Mine work (AOR 4.01, 95% CI 1.62 – 10.00), factory work (AOR 4.01, 95% CI 2.00 – 10.00) supermarket work (AOR 2.11, 95% CI 0.90 – 5.00) increased chances of TB. ILTFU (3.10 95% CI 0.50 – 28.80), LTFU during continuation phase (AOR 2.11, 95% CI 1.30 – 17.00) increased incidence and mortality, and those who died (AOR 3.10, 95% CI 1.21 – 7.81) were most likely due to TB infection. Patients who were not evaluated (AOR 4.51, 95% CI (2.00 – 12.00) and those who relapsed (AOR 2.40, 95% CI 1.20 – 4.81) were positively associated with TB incidence and mortality.
Conclusion: There is a significant positive association between environmental factors of TB, TB incidence and TB mortality. Household overcrowding, exposure to silica dust (through mining), and working in factories and supermarkets are associated with TB incidence.
Recommendation: A strong collaborative effort between environmental health stakeholders and the national TB program to address environmental factors identified in this study.