Obese children may be more susceptible to the harmful effects of pollution than their normal-weight peers, US research results suggest.

Speaking at the American Thoracic Society International Conference in Orlando, Florida, lead researcher Dr Heike Luttmann-Gibson, from Harvard School of Public Health in Boston, Massachusetts, said: “Given the epidemic of obesity in children, it might be that we’re developing a population that is more susceptible to air pollution.”

Dr Luttmann-Gibson and her team studied 611 schoolchildren in Boston to investigate the short-term effects of air pollution - around 10% of whom were classed as obese. Each child’s lung function was measured and compared with levels of air pollution on the previous day.

The researchers found that the higher the level of air pollution on any given day, the worse the children’s lung function became on the following day, with a greater effect seen among children classed as obese. Indeed, the association between pollution and lung function was found to be two to five times stronger among obese children than those of normal weight.

Dr Gibson explained that fatty tissue releases a substance called interleukin 6, which is known to promote inflammation, and that other markers of inflammation, such as increased white blood cell counts, and elevated levels of C-Reactive protein are found in the blood of obese children and adults. “Since air pollution also leads to inflammation of the airways, we think there is a multiplier effect that makes obese children more sensitive to air pollution,” she said.

“Obesity in childhood causes a host of problems, including increased risk of diabetes, heart problems and asthma,” added Dr. Gibson. “This study indicates that susceptibility to air pollution is one more harmful effect of childhood obesity.”