Children who have an early-life history of asthma or wheezing are at higher risk for obesity, according to a new study.
The likelihood of becoming obese over the next decade was 51% greater in young children who had asthma than in those who did not.
The use of asthma rescue medications reduced the risk of becoming obese by 43%, the researchers noted.
“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, or both,” said lead author Zhanghua Chen, PhD, a postdoctoral research associate of preventive medicine at the Keck School of Medicine at the University of Southern California. “Our findings add to the literature that early-life asthma history may lead to increased risk of childhood obesity.”
The mechanisms that link obesity and asthma may include obesity-influenced lung physiology, such as reductions in pulmonary compliance and limitations in airflow, systemic inflammation, dysfunctions of the sympathetic nervous system, and common genetic factors, the researchers noted.
Also, children with asthma are known to have reduced levels of physical activity and may potentially suffer from the adverse effects of corticosteroid medications that increase their risk of obesity.
The prospective study by Chen and colleagues included a long-term follow-up of a cohort of 2171 kindergarteners and first graders who were not obese at the time they enrolled in the Southern California Children’s Health Study (CHS). At enrollment, 13.5% of the children had asthma; they were followed for up to 10 years, on average for 6.9 years. Over that time, obesity developed in 15.8% of the children.
The researchers confirmed the study results in an independent sample of 2684 CHS children followed from a mean age of 9.7 to 17.8 years.
The researchers took into account a number of potential factors that might have biased the results, including whether the children had health insurance or were overweight at enrollment, ethnicity, family income, smoking exposure at home, and physical activity.
The overall study findings reinforce the importance of early diagnosis and treatment of asthma, which 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. Since asthma treatments are largely efficacious, they may have the potential to help prevent obesity through early diagnosis and treatment of childhood asthma,” the researchers stated.
Study limitations included relying on parents to report asthma diagnosis, limited information about exercise, and no information about diet.
The researchers said they were surprised that rescue, but not controller, asthma medications reduced obesity and noted that this result warranted further study.
They suggested early interventions for children with asthma or wheezing or both “to prevent a vicious cycle of worsening obesity and asthma that could contribute to the development of other metabolic diseases, including prediabetes and type 2 diabetes in later life.”
The researchers published their results online January 19, 2017 in the American Journal of Respiratory and Critical Care Medicine.