The age-specific burden and household and school-based predictors of child and adolescent tuberculosis infection in rural Uganda

Abstract

Background: The age-specific epidemiology of child and adolescent tuberculosis (TB) is poorly understood, especially in rural areas of East Africa. We sought to characterize the age-specific prevalence and predictors of TB infection among children and adolescents living in rural Uganda, and to explore the contribution of household TB exposure on TB infection.

Methods: From 2015-2016 we placed and read 3,121 tuberculin skin tests (TST) in children (5-11 years old) and adolescents (12-19 years old) participating in a nested household survey in 9 rural Eastern Ugandan communities. TB infection was defined as a positive TST (induration ≥10mm or ≥5mm if living with HIV). Age-specific prevalence was estimated using inverse probability weighting to adjust for incomplete measurement. Generalized estimating equations were used to assess the association between TB infection and multi-level predictors.

Results: The adjusted prevalence of TB infection was 8.5% (95%CI: 6.9-10.4) in children and 16.7% (95% CI:14.0-19.7) in adolescents. Nine percent of children and adolescents with a prevalent TB infection had a household TB contact. Among children, having a household TB contact was strongly associated with TB infection (aOR 5.5, 95% CI: 1.7-16.9), but the strength of this association declined among adolescents and did not meet significance (aOR 2.3, 95% CI: 0.8-7.0). The population attributable faction of TB infection due to a household TB contact was 8% for children and 4% among adolescents. Mobile children and adolescents who travel outside of their community for school had a 1.7 (95% CI 1.0-2.9) fold higher odds of TB infection than those who attended school in the community.

Conclusion: Children and adolescents in this area of rural eastern Uganda suffer a significant burden of TB. The majority of TB infections are not explained by a known household TB contact. Our findings underscore the need for community-based TB prevention interventions, especially among mobile youth.

Conflict of interest statement

The authors have declared that no competing interests exist.

Figures

Fig 1. Study flow diagram.

TST = tuberculin skin test.

Fig 2. Histogram of non-zero induration from tuberculin skin tests.

Among the 3,121 children who had TSTs placed and read, 2425 (77.7%) had an induration of 0 millimeters (mm) and 696 (22.3%) had a non-zero mm induration. The mode of non-zero indurations was 8mm.

Fig 3. Population-level age-stratified prevalence estimates of TB infection, defined as a positive tuberculin skin test (TST), in duration >10mm or >5mm if living with HIV.