- Design
- Systematic review and meta-analysis of 12 observational studies
- Population
- 6,411 children and adolescents in low-resource settings
- Primary outcome
- TB infection or disease
- Effect
- Pooled OR about 2.69 for household second-hand smoke exposure; I² 0%
A meta-analysis of 12 observational studies (6,411 children and adolescents in low-resource settings) found that household second-hand smoke exposure was associated with higher odds of TB infection or disease, a pooled odds ratio of about 2.7 with no heterogeneity between studies. There was some sign of publication bias.
Smoke exposure impairs airway defences and macrophage function, so the link is biologically plausible. But households with smokers may differ in crowding, poverty and contact with adult TB cases, so the association is not proof of cause.
In India, where household smoking and childhood TB are both common, asking about smoking at home during contact tracing and TB preventive therapy visits is a cheap addition.
- Ask about smoking in the home when assessing a child for TB or TB contact
- Advise smoking cessation for household members of children with TB or TB contacts
- Count household smoke exposure as part of a child's TB risk picture
- Present the link to families as an association with a plausible mechanism
Why it matters
A modifiable household exposure may add to a child's TB risk.
Don't overread it
These are observational studies; household smoking may mark other TB risks such as crowding and adult contacts.
The statistics, in plain English
An odds ratio of about 2.7 means the odds of TB infection or disease were nearly three times higher in exposed children. Odds ratios exaggerate relative risk when the outcome is common, as latent infection often is.
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