Rates of asthma are on the rise in children, and doctors have struggled to figure out why.
The researchers found that the chance that a child was diagnosed with asthma was significantly greater if the child was obese. They found that 23 to 27 per cent of new cases of asthma in the children were directly attributable to obesity.
They also found a link between being overweight and having asthma. However, the link between overweight and asthma was not as strong as was the link to asthma in kids with obesity.
The connection is not well understood, but there are some theories. One is that carrying extra weight around the chest might predispose children to asthma by narrowing the airways or restricting the chest to shallow breaths. Studies have shown that obesity reduces the volume of air that can be inspired into the lungs.
Another hypothesis is that adipose or fatty tissue releases chemicals called adipokines that increase inflammation inside the body. The “excess” inflammation caused by adipokines makes the airways more sensitive to environmental triggers like cat and dog dander that can set off asthma attacks.
Another theory is that obesity triggers a third condition such as acid reflux and obstructive sleep apnea that in turn trigger asthma. None of these have been proven.
Some researchers believe the connection between obesity and asthma is just a coincidence of two common conditions. Some believe asthma is the result of obesity rather than the cause.
Currently, there are few known prevention factors that can be used to reduce childhood asthma. Reducing obesity would be good for children. It would also reduce significantly the burden of asthma and obesity on the health-care system.