Obese children may have more asthma complications

3 November 2017: Children with asthma who are also obese are admitted to the hospital more often for asthma complications, according to a recent study in Japan.

Among children ages 3 to 8 hospitalized for asthma, the obese patients were also more likely to be re-admitted to the hospital within 30 days and to stay at the hospital for a longer period of time, researchers found.

“The prevalence of asthma (in children in developed countries) is high, and it is also one of the major reasons for hospitalizations among children,” said lead author Yusuke Okubo of the National Research Institute for Child Health and Development in Tokyo.

“Asthma is a chronic disorder, and poor control of asthma may result in lower quality of life, school performance and self-confidence,” Okubo told Reuters Health by email.

The study team investigated nearly 39,000 hospital discharge records for children between 2010 and 2015, classifying the patients as underweight, normal weight, overweight or obese according to World Health Organization body mass index (BMI) categories. Eight percent of kids were underweight, 75% normal weight, 9% overweight and 8% obese.

The researchers then compared 30-day hospital readmission, need for intensive care, average total hospital costs and length of hospital stay among all patients.

They found that kids in all four weight groups had similar needs for intensive care and total costs for hospitalization. Obese children hospitalized with acute asthma problems were 26% more likely to be readmitted to the hospital within 30 days, however, and their average hospital stays were slightly longer than those of normal-weight kids.

“We assumed that children with obesity were more likely to be hospitalized repeatedly,” Okubo said. “At this time, we are not sure the exact biological mechanisms for the associations between asthma and obesity.”

Potential risk factors for asthma include age, race and ethnicity, socioeconomic status, medication adherence, access to health care and a history of sinusitis, the study authors write online October 18 in Pediatric Allergy and Immunology. A 2013 review of 35 studies also found that gender plays a role, with obese girls more likely to have asthma diagnoses than obese boys, they note.

“The obesity-asthma link appears to be more prominent in girls, which is consistent with several study findings in adult populations where obese women are more likely to have asthma or worse asthma control,” said Pei-Ching Liu, a researcher at National Taiwan University in Taipei who wasn’t involved in the study.

“There is still no satisfactory explanation of the underlying mechanism,” Liu told Reuters Health by email. “However, hormones or changing body composition have been implicated since early onset of puberty in children.”

In a previous study using data on more than 74,000 children in the U.S. who had asthma exacerbations in 2012, Okubo and her colleagues found that obese children had nearly double the odds of using mechanical ventilation, an average of $1,600 more in hospital charges and spent a quarter of a day longer in the hospital.

“Pediatric obesity is a public health problem and is associated with infections, chronic disorders, asthma and future heart disease,” Okubo said. “Weight reduction and a healthy lifestyle is important for children to control asthma severity.”