(Reuters Health) – A US study UU It suggests that children and adolescents who are overweight or obese may be more likely to develop asthma.
While obesity has been linked to asthma in adults, research to date has offered contradictory evidence on whether this is also true for young people, researchers at Pediatrics point out.
The current study followed more than 500,000 children, aged two to 17, for an average of four years. In general, about eight percent had been diagnosed with asthma.
According to the study, compared to children with healthy weight, overweight children were 17 percent more likely to have a diagnosis of asthma and young obese were 26 percent more likely to have a diagnosis of asthma. This was based on a diagnosis or prescription of asthma medication, but not on the results of breathing tests.
When researchers looked at the connection between asthma and obesity based on so-called spirometry tests that show how easily people can breathe the air in their lungs, the bond was stronger. The study found that obesity was associated with a 29 percent higher risk of asthma based on this more stringent diagnostic criteria.
The study was not a controlled experiment designed to test whether overweight or obesity can cause asthma directly, but the results offer some of the most convincing evidence to date that suggests a connection exists, said the study's lead author, Dr. Jason Lang of Duke University School of Medicine in Durham, North Carolina.
"Experts have speculated that the abnormal growth of the lungs associated with obesity causes an obstruction of the air flow," Lang said by email.
Obesity can also trigger the development of so-called cardiometabolic risk factors such as high cholesterol and the inability to use the hormone insulin to contribute to blood sugar in energy that can lead to deterioration in the airways, Lang added.
"Several studies have shown that asthma symptoms improve a lot with weight loss, but the exact mechanism is unknown," said Lang.
The researchers calculated that between 23 and 27 percent of new cases of asthma in children with obesity can be directly attributed to obesity.
If no child was overweight or obese, 10 percent of asthma cases would be avoided, they estimated.
One of the limitations of the study is that the researchers rely on the medical records that the doctors carry, and the documentation of an asthma diagnosis or the order of spirometry is at the discretion of the doctors, the researchers point out.
It is also impossible to determine from the study whether asthma can lead to obesity or if obesity can lead to asthma.
Even so, the results suggest that it is possible to prevent the development of asthma by helping children maintain a healthy weight, said Dr. Deepa Rastogi, director of the Pediatric Asthma Center at Children's Hospital at Montefiore in Bronx, New York.
Even with asthma, children can exercise to help them reach and maintain a healthy weight, Rastogi said in an email.
"Children with asthma can be as active as they want to be, we have had Olympic-level athletes with asthma," said Rastogi, who wrote an editorial that was published with the study.
"There is no activity that children with asthma should avoid," Rastogi added. "They should be aware of their symptoms and, if they associate a particular activity with asthma, they should take their asthma medication called albuterol 20 to 30 minutes before participating in that activity."
SOURCE: bit.ly/2TLbCYJ Pediatrics, online November 26, 2018.