There could be a link between secondhand smoke and an increased risk of Mycobacterium tuberculosis infection in children living in the same home as someone with TB, according to a study published in the April issue of Pediatrics.
The finding could be a "cause of great concern considering the high prevalence of smoking and tuberculosis in most developing countries," Saskia den Boon of KNCV Tuberculosis Foundation in the Netherlands said.
For the study, den Boon and colleagues surveyed 15% of the addresses in two adjacent low- to middle-income communities in Cape Town, South Africa. The study included all children under age 15 years in the communities, as well as adults living at the same address. All the children received a tuberculin skin test for the study.
Researchers defined M. TB infection as a reaction of at least 10mm, and secondhand smoking as residing with at least one adult who smoked for at least one year. Of the 1,344 children surveyed, 432 -- or 32% -- had a positive tuberculin skin test, and 1,170 -- or 87% -- were identified as secondhand smokers, the study said.
The researchers found that the rate of positive tuberculin skin tests in children who were considered secondhand smokers was 34%, compared with 21% in children not living with a smoker. Although the difference was not statistically significant, the researchers found that there was a significant link between secondhand smoking and a positive tuberculin skin test in the 172 households that included someone living with TB.
In those homes, children were five times more likely to test positive, the study found. Secondhand smoking "might affect the immune system of the child, thus increasing the risk of getting infected," the researchers said.
According to the researchers, smoking is becoming more common in many developing countries with high TB prevalence, especially among women. They added that this is worrisome "because they expose their children to tobacco smoke"
Source: Kaiser Family Foundation