Overweight, obese kids have higher asthma risk

Reuters Health: Children and teens who are overweight or obese may be more likely to develop asthma, a US study suggests.

While obesity has long been linked to asthma in adults, research to date has offered conflicting evidence about whether this also holds true for young people, researchers note in Pediatrics.

The current study followed more than 500,000 kids, ages two to 17, for an average of four years. Overall, about 8% had been diagnosed with asthma.

Compared to kids at healthy weight, overweight children were 17% more likely to have an asthma diagnosis and obese youth were 26% more likely to have an asthma diagnosis, the study found. This was based on a diagnosis or asthma drug prescription but not on breathing test results.

When researchers looked at the connection between asthma and obesity based on so-called spirometry tests that show how easily people can breathe air out of their lungs, the link was stronger. Obesity was associated with a 29% higher risk of asthma based on this stricter diagnostic criteria, the study found.

The study wasn’t a controlled experiment designed to prove whether or how being overweight or obese might directly cause asthma, but the results offer some of the most compelling evidence to date suggesting that there is indeed a connection, said lead study author Dr. Jason Lang of Duke University School of Medicine in Durham, North Carolina.

“Experts have speculated that abnormal lung growth associated with obesity causes airflow obstruction,” Lang said by email.

Obesity can also trigger the development of so-called cardiometabolic risk factors like high cholesterol and an inability to use the hormone insulin to contribute blood sugar into energy that may lead to impairment in the airway, Lang added.

“Several studies have shown that asthma symptoms get much better with weight loss but the exact mechanism is unknown,” Lang said.

(Source: bit.ly/2TLbCYJ Pediatrics, online 26 November.)