Not all kids are affected the same way by exposure to smoke in their environments. Tobacco smoke is a complex mixture of toxic gases and toxic particles, over 4000 chemicals in all. Repeated exposure will cause asthma in some children, but not in others. Is there any way to tell which are which? We know that about half of children are capable of producing large amounts of enzymes (glutathione S transferases – GST) that can help them detoxify the chemicals in the smoke.
Researchers in Germany did genetic testing on over 3,000 schoolchildren, aged 9 to 11. The results were published in the July 2004 Thorax. More than half of the children were missing a key gene to make GST. For those missing the gene, the risk of smoke exposure was highest. Those who were exposed were more than 5 times more likely to have developed asthma than their peers. Someday soon, a test like this may be available routinely and inexpensively.
In the meantime, it makes sense to me that if there is a genetic tendency toward asthma . in other words, if asthma, eczema, or allergies run in the family – then exposure to secondhand smoke is probably even more dangerous for your child than for other children. Kids deserve to breathe clean, fresh air.