By Bridget M. Kuehn
WebMD Health News
January 20, 2017
Children who are diagnosed with asthma are more likely to become obese later in childhood, according to a study published in the American Journal of Respiratory and Critical Care. Treatment with rescue inhalers may help mitigate the risk, the researchers report.
"Asthma and obesity often occur together in children, but it is unclear whether children with asthma are at higher risk for onset of obesity or whether obese children develop asthma," said lead author Zhanghua Chen, PhD, from the Keck School of Medicine at the University of Southern California-Los Angeles in a press release. "Our findings add to the literature that early-life asthma history may lead to increased risk of childhood obesity."
To probe the relationship between asthma and obesity, Chen and her colleagues analyzed data on 2171 children who enrolled in the Southern California Children's Health Study between the ages of 5 and 8 years and who were not obese at enrollment. Children in the study were followed for up to 10 years after enrollment. Children were measured and weighed each year to determine their body mass index, and parents or children reported their asthma status.
Children with asthma at study entry had a 51% higher risk for obesity during childhood or adolescence compared with those who started the study without asthma (hazard ratio [HR],1.51; 95% confidence interval [CI],1.08 - 2.10) after adjustment for socioeconomic factors, children's activities, health insurance, and exposure to parental smoking.
The researchers confirmed their finding by analyzing data on a separate group of 2684 children enrolled in the same study. In the replication cohort, baseline asthma was associated with a 56% increased risk for obesity during follow-up of approximately 8 years (HR, 1.56; 95% CI, 1.11 - 2.19).
Use of rescue inhalers — but not other asthma medications — at study enrollment appeared to mitigate the risk for obesity in the original cohort. Children with asthma who used rescue inhalers at study entry had nearly half the risk for obesity compared with children with asthma who were not using these medications (HR, 0.57; 95% CI, 0.33 - 0.96).
The authors speculate that β-agonist rescue inhalers may protect against obesity via their effects on fat cells and fat utilization. They noted that both fat and muscle cells have receptors that β-agonist drugs may act on and that animal studies have shown that stimulating these receptors boosts energy expenditure and fat burning.
One limitation of the study is that parents and or children reported asthma status and could have misreported the diagnosis. The study also collected only limited information on physical activity and no information on diet. The authors suggest that future studies that directly measure body fat and its distribution are needed to confirm the findings.
The authors conclude that the study emphasizes the importance of initiating asthma treatment as soon as possible.
"Early diagnosis and treatment of asthma may avoid the vicious cycle of asthma increasing the development of obesity with obesity subsequently causing increased asthma symptoms and morbidity leading to further weight gain," Dr Chen and her colleagues wrote.
Dr Chen and her colleagues have disclosed no relevant financial relationships.