Risk factors associated with paediatric tuberculosis in an endemic setting

Abstract

Background: The success of any tuberculosis (TB) control/intervention programme hinges on the understanding of transmission dynamics of TB within that setting. However, there is paucity of data in high disease burdened countries like Nigeria on the associated risk factors of childhood TB and this supports the need for this research.

Objective: This study was undertaken to determine the prevalent associated risk factors of childhood pulmonary TB in a high diseased burdened setting.

Subjects and method: We carried out a cross sectional study among children aged 18 months to 15 years in six selected health facilities in Nasarawa State, Nigeria. The subjects were screened for pulmonary TB using chest X-ray, sputum or gastric aspirate acid-fast bacilli microscopy and mycobacterium culture. They were also screened for HIV infection. Detailed information was taken regarding history of contact with adult TB source case, house-hold contact, duration of contact, house-hold size, number of people sleeping in a room, cross ventilation, BCG immunization, socio-economic, educational and HIV status of parents, and ingestion of unpasteurized milk and chronic illness other than TB. The subjects had physical examination for BCG scar and nutritional status.

Results: A total of 150 subjects were selected for the study with mean age of 9.12 ± 4.66 years and median age of 10.0 years. The prevalence of definite TB cases found among them was 32% which is 5.5 times higher than the reported national average. The risk factors associated with pulmonary TB include lower socioeconomic status (79.2%), history of contact with an adult TB case source (72.9%), overcrowding (72.9%), absence of cross ventilation (68.8%), ingestion of unpasteurized milk (45.8%) and severe malnutrition among children under five using MUAC parameter (12.5%). The most significant independent predictors of TB in children were absence of cross ventilation (OR = 3.27), contact with adult source case (OR = 2.91) and overcrowding (OR = 2.30).

Conclusion: Absent of cross ventilation, contact with adult source case and overcrowding are the most significant predictors of pulmonary TB in children. Although ingestion of unpasteurized milk is a significant predictor and important source of TB, it is not a major source of TB transmission when compared to contact with adult source case (Open TB).