- Design
- Systematic review and meta-analysis of 12 observational studies
- Population
- 6,411 children and adolescents aged 0–18 in low-resource settings
- Primary outcome
- TB infection or disease
- Effect
- Pooled OR 2.69 with household second-hand smoke; I² 0%
This meta-analysis pooled 12 observational studies from low-resource settings, covering 6,411 children and adolescents aged 0 to 18. It compared those with and without household second-hand smoke exposure.
Exposed children had about 2.7 times the odds of TB infection or disease (pooled OR 2.69), with no measurable heterogeneity between studies. There was some sign of publication bias.
Smoke impairs airway clearance and local immunity, and smoking adults in a household are themselves at higher TB risk, so exposure to smoke and exposure to an infectious case overlap. The studies cannot separate those two pathways.
For Indian practice, where both household smoking and TB are common, it adds weight to asking about smokers at home during any childhood TB evaluation.
- Ask about smokers in the household when evaluating a child for TB.
- Treat household smoking as a reason for a lower threshold to screen exposed children.
- Offer smoking cessation support to parents and carers of children with TB.
- Screen adult smokers in the household for TB symptoms as part of contact tracing.
Why it matters
It links two common household exposures that most childhood TB assessments treat separately.
Don't overread it
This was observational; it cannot show that smoke itself causes TB in children.
The statistics, in plain English
A pooled odds ratio of 2.69 with I² of 0% means the studies agreed closely. But these are observational studies, and smokers in a household may also be more likely to have TB themselves, so part of the association may reflect exposure to an infectious adult rather than to smoke.
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