Obese kids have more asthma flare-ups

Shaving off extra pounds might help asthmatic kids prevent flare-ups of the disease, according to a study that found obese children have a harder time controlling their symptoms.

The work is the first to show that even after taking race and social factors into account, heavier kids use more drugs to control their asthma and curb flare-ups than their slimmer peers.

“Improving nutritional status, preventing obesity, and stressing the importance of weight loss might improve asthma control and exacerbation risk in children and decrease the incidence of asthma in adults,” researchers write in the Journal of Allergy and Clinical Immunology.

Both asthma and obesity rates have soared among kids in recent decades, reaching nearly 10 percent and 17 percent today, respectively.

While some studies have hinted at a link between the two conditions, conclusions on whether heavier kids also have more severe asthma than others have been mixed.

The association between obesity and asthma severity and control in children is not well understood.

The objective of this study was to examine the association of childhood body mass index (BMI) percentile for age of 85% or greater with the number of β-agonist canisters dispensed, corticosteroid courses, emergency department visits, and hospitalizations for asthma.

A retrospective cohort of 32,321 children aged 5 to 17 years and given a diagnosis of asthma who received at least 1 asthma (controller or rescue) medication and were enrolled in Kaiser Permanente from 2004-2008 was identified. Outcomes from electronic medical records included β-agonist canister and nebulizer units dispensed per year, hospitalizations and emergency department visits for asthma exacerbations, and oral corticosteroid courses. Potential confounding factors known to influence asthma outcomes were also collected: demographics, parental education level, asthma controller use, gastroesophageal reflux disease diagnosis, and diabetes mellitus diagnosis. Multiple logistic regression models were used to measure the independent association of BMI status with outcomes.

Even after adjusting for demographics, parental education level, asthma controller use, and gastroesophageal reflux disease and diabetes mellitus diagnoses, overweight (BMI percentile for age, 85% to 94%) and obese (BMI percentile for age, ≥95%) children were more likely to have increased β-agonists dispensed (odds ratio of 1.15 [95% CI, 1.02-1.27] and odds ratio of 1.17 [95% CI, 1.06-1.29], respectively) and increased risk for oral corticosteroids dispensed (odds ratio of 1.21 [95% CI, 1.13-1.29] and odds ratio of 1.28 [95% CI, 1.21-1.36], respectively) compared with normal-weight (BMI percentile for age, 16% to 84%) children.

Dr. Kenneth B. Quinto from the University of California, San Diego, and colleagues looked back at more than 32,000 kids who’d been diagnosed with asthma and were enrolled in a Kaiser Permanente health plan. Nearly half of the children were overweight or obese.

The researchers found that the heavier kids were more likely to have more than a handful of yearly prescriptions for rescue inhalers, which contain short-acting drugs such as albuterol that open up the airways when an asthma attack is coming on.

On average, normal-weight children used 2.8 rescue inhalers a year, whereas obese kids used 3.1.

The heavy youngsters also used more inhaled steroids, such as Pulmicort or Flovent, which are a mainstay treatment to keep airway inflammation under control on a daily basis in asthmatics.

And the results held up after Quinto and his colleagues accounted for alternative explanations of the differences, such as sex, race, diabetes and parents’ education levels.

The team speculates that the extra pounds might be weighing on the lungs, making obese kids feel like they need more medication. Scientists have also found that overweight people don’t respond as well as others to steroids, which might help explain the new findings.

Still, in an observational study like theirs, the researchers warn it’s never possible to be certain what causes what. So whether bigger waistlines should be blamed for the extra flare-ups remains an open question.

Meanwhile, the team writes, “The best time for prevention of obesity and nonsurgical weight reduction likely occurs in childhood.”


Kenneth B. Quinto MD, MPH, Bruce L. Zuraw MD, Kwun-Yee T. Poon, Wansu Chen, Michael Schatz MD, MS and Sandra C. Christiansen MD
SOURCE:  Journal of Allergy and Clinical Immunology, online August 6, 2011.

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