Secondhand smoke exposure is worse for toddlers and obese children, according to a new study.
The researchers, who presented their study at the American Heart Association's Scientific Sessions 2009, observed 52 toddlers (ages 2 to 5 years) and 107 adolescents (ages 9 to 18 years) to reach their conclusion.
They noted that there was a link between the amount of secondhand smoke exposure and a marker of vascular injury in toddlers. This link was two times greater in toddlers who were obese.
Also, obese adolescents exposed to secondhand smoke had two times the evidence of vascular injury compared to normal-weight adolescents.
It was found toddlers had a four times greater risk of secondhand smoke exposure when compared to adolescents, despite having similar reported home exposures.
Toddlers exposed to secondhand smoke had a 30 percent reduction in circulating vascular endothelial progenitor cells, a cell type involved in repair and maintaining a healthy blood vessel network.
John Anthony Bauer, Ph.D., the study's senior co-author and principal investigator at Nationwide Children's Hospital and Research Institute at Ohio State University in Columbus, said: "Secondhand smoke in children is not just bad for respiratory issues, as has been previously described by other researchers.
"Our data support the view that cardiovascular effects of secondhand smoke in children are important, particularly for the very young and those who are obese. We had not investigated the impact of obesity in previous studies."
He added: "We do know that secondhand smoke as well as smoking causes increased oxidation and inflammation.
"Separately, other studies within the past few years have shown that obesity is a physiological condition of chronic low-grade inflammation, and that this can lead to vascular damage. We think that the two factors together (eg., smoke exposures plus obesity) may interact to amplify the degree of inflammation or vascular cell damage that occurs.
"Our findings add to the importance of eliminating smoking and related exposures, especially for children, and obese children may need to be even more protected from these exposures."