Washington, Jan 29: Exposure to second-hand smoking may make children obese and amplify their risk of cardiovascular disease and diabetes, a new study has warned.
Researchers looked at passive smoke exposure in 220 overweight or obese boys and girls aged between 7 and 11 years. They found smoke exposure associated with nearly all measures of adiposity in the children, including bigger bellies and overall fat.
"Every single one of our cognitive measures was poorer in the smoke-exposed children," said Catherine Davis from Medical College of Georgia at Augusta University in US.
Percentages of body fat in smoke-exposed children were substantially higher than in their also heavy peers, further amplifying their risk of cardiovascular disease, diabetes and more, she said.
"All the bad things fat does to us, passive smoking makes worse," said Martha S Tingen from Augusta University.
"And children who were exposed to second-hand smoke scored poorer on all cognitive tests, shortfalls that can translate to a poorer attention span and lower grades in the classroom and on standardised tests," she added.
Researchers collected both parental reports of their children's smoke exposure as well as blood levels of cotinine, the major metabolite of nicotine, which is often used as a definitive test of smoking or passive smoke exposure.
They also assessed levels of physical activity, which can impact fatness, sleep and diabetes risk. They found surprisingly that passive smoke exposure did not appear to worsen breathing problems, such as snoring and short periods of not breathing while the children slept.
It also appeared unrelated - at least at this early age - to prediabetes, insulin resistance and fat around internal organs in the abdomen.
Fat around the organs is considered a particularly high-risk factor for vascular disease and diabetes and ultimately heart disease and stroke.
However, the larger waist size found in the children exposed to smoke also is considered a risk factor for these obesity-related health problems.
The study found passive smoke had an impact on cognition that was independent of fat or socioeconomic status.
"If you are breathing in second-hand smoke, it is almost as bad as if you were smoking the cigarette yourself," said Tingen.
Tailored interventions covering nutrition, physical activity and tobacco use in children and their families affected by these adverse health scenarios are needed to prevent adverse outcomes, researchers said. The findings were published in the journal Childhood Obesity.