Risk factors for pulmonary tuberculosis among health-care workers in Ibadan, Nigeria

Data on TB infection control programs is limited in many of the TB high burden countries. We carried out a one-year cross sectional epidemiological study (January-December, 2008) to determine the prevalence of occupationally-acquired pulmonary tuberculosis (PTB) among Health- Care Workers (HCWs) in Ibadan, Nigeria. This information is important for planning preventive strategies. All consenting HCWs at two TB centres in Ibadan--the University College Hospital (UCH) and Jericho Chest Hospital were enrolled into the study. A well structured questionnaire was used to obtain information on socio-demographic characteristics of the subjects including their medical and social data. Three sputum samples collected from each subject were processed for acid-fast bacilli (AFB) and culture on selective medium. Isolates were confirmed as M. tuberculosis by standard biochemical tests. Of the 271 subjects recruited, nine (3.3%) had their sputum positive for AFB while six (2.2%) were positive for culture. Subjects aged 20 years and above, female gender and unskilled professionals had higher risk for occupationally-acquired PTB than those who were 20 years and below, male gender and skilled professionals (Odd Ratio OR = 1.9, 95% Confidence Interval, 95% CI = 0.23-16.3, Fisher's exact P = 0.37; OR = 1.1, 95% CI = 0.28-4.0, p = 0.01; OR = 1.05, 95% CI = 1.02-1.08, p = 3.43) respectively. Multivariate logistic regression analysis showed that subjects who received BCG vaccination were less likely to have occupationally-acquired PTB than those without vaccination (OR = 0.86, 95% CI = 0.20-3.6, p = 0.83 for microscopy; OR = 0.76, 95% CI = 0.13- 0.44, p = 0.76 for culture). Even though the risk for occupationally-acquired PTB was lower in subjects who had not spent up to two years in their units, the association was not statistically significant (OR = 0.84, 95% CI = 0.20-3.5, p = 0.82 for microscopy and OR = 1.21, 95% CI = 0.22-0.65, p = 0.82 for culture). There is a need to develop and implement affordable and cost-effective TB infection control strategies in Nigeria in order to reduce the burden of occupationally-acquired PTB in the country.