Obesity May Raise Kids' Asthma Risk
Breathing Problems During Sleep Also Raise Risk
Childhood obesity and asthma may be connected, but it's not clear which
Children with an active wheeze had significantly higher BMI and a greater
prevalence of obesity, write researchers. Although there is speculation that
asthma predisposes to obesity by reducing physical activity, this has not been
shown to be the case. However, recent studies show that obesity precedes the
development of asthma.
Both conditions are rising among American kids and adults, and asthma is
increasing in developing countries worldwide.
There seems to be a relationship between asthma and obesity -- and trouble
breathing during sleep could be part of the puzzle, a new study shows.
Sleep-disordered breathing, characterized by snoring, could be the pathway
mediating asthma and obesity.
That's the latest news in the ongoing debate about asthma and obesity.
New Findings on Obesity and Asthma
Doctors at Cleveland's Case School of Medicine recently studied 788 kids
aged 8-11 years for asthma, wheeze, obesity, and breathing problems during
sleep. The researchers made sure enough minority and prematurely born children
The children's height, weight, and history of wheeze and asthma were noted.
The kids took a breathing test and sleep studies were done at home using
monitors. Disordered sleep disturbances were defined either by sleep apnea or
by snoring habits. In sleep apnea, people regularly stop breathing for 10
seconds or longer during sleep.
The vast majority of the kids (600) had no breathing problems. Kids with
wheezing/asthma had the usual risk factors such as being male, black, born
prematurely, and had a mother with a history of asthma. Yet kids with
wheezing/asthma were also more likely to have a higher BMI.
Obesity was significantly associated with both asthma and wheeze. It nearly
doubled the risk of asthma, raising the risk by 1.8 times. Obesity also raised
the risk of wheeze 1.6 times.
By comparison, about 14% of the kids without wheeze or asthma were
classified as obese -- identified as being heavier than 95% of their peers.
Does Sleep Play a Role?
Problems breathing during sleep also seemed to be important.
About one in three children with asthma or wheezing had sleep-disordered
breathing. In contrast, only about one in six kids without wheezing or asthma
had sleep-disordered breathing.
"Children with sleep-disordered breathing had nearly twice the odds of
wheeze compared with those without," write Loreto Sulit, MD, and
Taking into account sleep-disordered breathing weakened the association
between wheezing and obesity, but it did not alter the link between asthma and
Which Comes First: Asthma or Obesity?
If asthma and obesity are intertwined, it's still not clear how that
Perhaps obesity constricts airways, say the researchers. Or maybe obesity
triggers asthma through hormonally driven inflammation, they note. Then again,
children with asthma may be less active, driving them towards obesity, say the
They're not sure. Their study didn't have objective measures of the kids'
physical activity, so they can't say either way.
The study appears in the March 15 issue of the American Journal of
Respiratory and Critical Care Medicine.