Environmental tobacco smoke exposure increases  Mycobacterium tuberculosis infection risk in children.
BACKGROUND
Data on the association between exposure to environmental tobacco smoke (ETS) and Mycobacterium tuberculosis infection in children are limited.


OBJECTIVE
To examine the dose-response effect of ETS exposure on the risk of M. tuberculosis  infection in children  in a high tuberculosis (TB) burden setting.


METHODS
This cross-sectional study included healthy South African children from impoverished urban communities. Data were collected on household ETS and  M. tuberculosis  exposure, demographics, socio-economic and anthropometric data, M.  tuberculosis  infection, human immunodeficiency virus and TB disease status.


RESULTS
Among 196 children (median age 6.8 years, range 0.3-15.9), 97 (49.5%) were M. tuberculosis - i nfected (tuberculin skin test [TST] ≥ 10 mm) and 128 (65.3%) reported ETS exposure; of these,  81/128 (63.3%) were exposed to ≥ 2 household smokers. The presence of ≥ 2 household smokers was associated with  M. tuberculosis  infection in univariate analysis, irrespective of TST cut-off point. In analysis adjusting for M. tuberculosis  exposure, socio-economic status,  age and previous TB treatment, ETS exposure remained associated with M. tuberculosis  infection. In univariate and multivariate analysis, pack-years of exposure were associated with risk of TB infection.


CONCLUSIONS
Exposure to ETS is associated with M. tuberculosis infection  in children after adjustment for multiple variables, with a dose-response relationship between the degree of ETS exposure and risk of infection. Public health interventions to reduce exposure to tobacco smoke among children in high TB burden settings are urgently needed.
Department of Paediatrics and Child Health, Desmond Tutu TB Centre, Stellenbosch University, Cape Town, Western Cape, South Africa. karen_dupreez@sun.ac.za
K
K
du Preez
A M
AM
Mandalakas
H L
HL
Kirchner
H M S
HM
Grewal
H S
HS
Schaaf
S S
SS
van Wyk
A C
AC
Hesseling
D000293:Adolescent; D000367:Age Factors; D016009:Chi-Square Distribution; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D004781:Environmental Exposure; D005260:Female; D006801:Humans; D007223:Infant; D016015:Logistic Models; D008297:Male; D009169:Mycobacterium tuberculosis / Q000472:pathogenicity*; D016017:Odds Ratio; D015995:Prevalence; D011446:Prospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013019:South Africa / Q000453:epidemiology; D011795:Surveys and Questionnaires; D013997:Time Factors; D014028:Tobacco Smoke Pollution / Q000009:adverse effects*; D014374:Tuberculin Test; D014376:Tuberculosis / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology* / Q000382:microbiology
D014028:Tobacco Smoke Pollution