Examining the Childhood Asthma Epidemic: Part 3

What Causes Asthma?

Ultimately, scientists don’t know why some people are prone to lung inflammation and sensitivity. Part of the answer is in our genes. A child’s chances of having asthma are greatest if his or her mother has the disease, second greatest if his or her father has it, and third greatest if the child has an allergy, Redding says. Approximately 75 to 80 percent of children with asthma have significant allergies, some of which may be inherited and some acquired by overexposure to specific substances they breathe or eat.

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Asthma is a disease of the immune system, which overreacts to stimuli by producing antibodies that result in the release of histamines. Histamines cause inflammation and secretion of mucus. On a cellular level, researchers are finding that asthmatics make too many of natural compounds called leukotrienes, which then cause swelling, constriction and mucus secretion. They are also looking into immune system proteins called cytokines, which carry messages between cells and seem to cause lung inflammation.

Sometimes there’s a thin line between a trigger for asthma and a cause. A study released earlier this year by the California Environmental Protection Agency’s Air Research Board found that children playing team sports in areas with high outdoor air pollution had higher asthma rates. These children did not previously have asthma symptoms, but developed new cases of the disease, according to researcher Rob McConnell, an associate professor of preventative medicine at the University of Southern California. The air pollution caused the asthma.

While it is not clear whether cigarette smoke is a trigger or a cause, studies have documented that children born to a mother who smokes or who live with a smoker are more likely to be asthmatic.

p.3 l next: p.4 - Why Are Asthma Rates Rising?

p.5 - Living with Asthma