Link between Obesity and Asthma

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New research points to a link between obesity and asthma
Rebecca Vesely

Breathing easier with healthier eating


KIMBERLY SOUTHALL was only 4 years old when she had an asthma attack so severe she punctured a lung.
Now 15, she has been hospitalized at least nine times for asthma and has tried dozens of medications. Throughout her childhood, she shied away from exercise and was overweight.

Then in 2001 she adopted a healthier diet, increased her vitamin intake and began exercising more. Although she still suffers from asthma, she hasn't been hospitalized for four years and is off prednisone, an oral steroid used to control asthma. She's lost 16 pounds in the past year.

It could be that Kimberly is outgrowing her asthma. But she — along with her medical team at Children's Hospital Oakland and her parents — thinks diet and exercise have something to do with it.

"How our diet affects us we don't totally understand," said Dr. Karen Hardy, director of the pulmonary and cystic fibrosis clinic at Children's Hospital Oakland. "But when people are eating right and exercising, they feel better across the board."


Medical researchers are starting to take a close look at connections between asthma and obesity — twin chronic conditions afflicting youths worldwide.

In a 2004 study, University of Arizona researchers tracked 800 children from ages 6 to 16 and found that kids who were overweight or obese at puberty were three times more likely to continue to have asthma problems into their later teen years than those who were not overweight or obese.

A Cleveland Case School of Medicine study of nearly 800 children ages 8 to 11 found that kids with wheezing or asthma were more likely to have a higher body mass index. The findings were published in the American Journal of Respiratory and Critical Care Medicine in March.

High incidence of asthma

In the Bay Area, both asthma and obesity are epidemics among youths. Asthma is the No. 1 reason for admission at Children's Hospital Oakland, a fact replicated at children's hospitals nationwide. In 2003, the hospital had 5,000 patient visits for asthma and about 1,400 admissions — double from 1999.

About one in five middle and high schoolers in the Oakland Unified School District has asthma. In East Oakland, the childhood asthma hospitalization rate is four times the national target, or one child in

100 under age 15. Americans spend $10 billion a year on childhood asthma medications and treatment.

Nationwide, more than 9 million children and youths between ages 6 and 19 are overweight, according to the Centers for Disease Control and Prevention. In Alameda, San Mateo and Contra Costa counties about

30 percent of seventh-graders are considered overweight or obese, according to state figures.

Asthma and obesity are like the chicken and the egg, researchers say: There is some link but it's unclear which comes first.

"We have seen huge changes in diet and activity level in children, and a huge increase in (television and video game) screen time, especially in urban settings where that may be the only safe thing to do," Hardy said. "We also know that when you're more fit, you will tolerate better more alterations in the airways."

Less likely to exercise

Asthma is defined as airflow restriction and inflammation of the airways. Asthmatic children are less likely to exercise for fear of aggravating their asthma, so they can become more sedentary and heavier.

Yet increased weight or obesity has been shown in studies to place an added burden on the lungs, triggering asthma where there was none.

The research is by no means conclusive. In other studies, weight loss has been linked to improved lung function but not improvement in airflow.

What researchers do know is that medications prescribed to control asthma — particularly the oral steroid prednisone, which Kimberly used for years — increases appetite and causes water retention. So while children may get relief from asthma, they also gain weight because of the medication.

"The steroid medications make them gain weight and having asthma makes them fearful of exercise, so they become less cardiovascularly fit," Hardy said.

Getting off the steroids can be tough. For Kimberly, that only happened after she switched to a more nutritious diet and began exercising more.

"Before, when I ran places, I would be like, I don't want to do that again," Kimberly said. "But we started eating more fruits and vegetables and I started feeling better. I noticed I could ride my bike more."

Kimberly's mom, Dorothy Southall, said she started feeding Kimberly more fruits and vegetables during her daughter's last hospital stay in 2001.

"Kimberly took it really seriously," Southall said. "I noticed she started refusing junk food. Everyone else would be eating chips and she would have an apple."

Kimberly is seventh out of a family of

10 children — and the seven children still living in the family home in Hayward are home-schooled. A rigorous daily schedule that includes time for vitamins and drinking eight glasses of water helps Kimberly stay on track. Two other siblings also have asthma but not nearly as bad as Kimberly.

Carrots, salad, potatoes, cauliflower, broccoli, celery and bananas are among Kimberly's favorite foods. But she still has a weakness for corn dogs, she said.

Linda Sugimura, a registered dietitian at Children's Hospital Oakland, works with Kimberly and other asthma patients to get on a healthy diet and stick to it. She advises at least five servings of fruits and vegetables each day and avoiding soda and foods that contain trans-fatty acids, such as french fries.

"Losing weight seems to help with the symptoms of asthma: There's less weight on the lungs so people can breathe better," Sugimura said.

Sugimura recommends foods high in antioxidants and omega 3 fatty acids, such as salmon and walnuts, which have decreased inflammation in the lungs in some studies.

Steroid medications to control asthma leech calcium out of the bones so people on such medications need to take more calcium, typically 300 mg more per day, Sugimura said.

Vitamin C, too, has been shown to alleviate asthma and other chronic airway illnesses such as cystic fibrosis.

"There is some connection between nutrition and asthma, and that's something you can do to get better," Sugimura said.

Nutrition and weight loss are by no means a silver bullet for controlling asthma. Asthma is caused by genetics; the environment, including pets, dust and pollution; and many other factors.

Gender may play a role in the link between obesity and asthma. A 2001 Harvard Medical School study indicated that the incidence of asthma after age 11 is five to seven times higher in females who become obese than females who stay at a healthy weight. There was no such link in males, according to the study.

Other signs

Asthma remains underdiagnosed because having asthma doesn't always mean constant wheezing. Frequent colds along with a cough that keeps a child up all night can be a sign of asthma, said Dr. Kimberly Morris, an emergency medicine doctor at Children's Hospital Oakland, who herself suffers from asthma.

"If it's 3 a.m. and the kid's coughing, throwing up and can't breathe and you go to the emergency room and the kid looks fine, it's probably asthma," Morris said.

Left undiagnosed or untreated, chronic asthma can lead to lung disease and irreversible changes to the air pathways.

The good news is that research has also shown that asthmatic children can lead active lives.

"If the asthma is controlled, these children can do anything any other child can do," Sugimura said.

These days, Kimberly loves to play soccer, swim and ride her bike. She believes that diet, exercise, vitamins and asthma medication all play a role in helping her keep ahead of the asthma.

On days she isn't active, she notices a difference.

"It feels wrong," she said. "You have to go do something."