Asthma and Antibiotics

[Guest guest]

By Fay Cortez

July 15 (Bloomberg) -- A stomach bacteria known to cause ulcers and

cancer in adults may also protect youngsters from developing asthma,

researchers said.

Children ages 3 to 13 infected with Helicobacter pylori were less

than half as likely to have asthma as those who didn't test positive

for the bacteria, according to the study in the Journal of Infectious

Diseases. They were also less likely to have signs of allergies, hay

fever and wheezing.

The findings support the ''hygiene hypothesis,'' which argues that a

sterile environment is shielding children from microbes needed for

the immune system to mature, the researchers said. Antibiotics have

been used to wipe out H. pylori since the 1990s, when it was shown to

cause ulcers and gastric cancer.

''We're beginning to understand the role of normal organisms in human

health,'' said Blaser, chair of medicine at New York

University Langone Medical Center, in a telephone interview

yesterday ''H. pylori was virtually universal, and now it's

disappearing. As rates go down, asthma is rising. We showed very

clearly that the absence of H. pylori was associated with asthma, hay

fever and allergy.''

People who are infected with the microbe have an immune response to

it, producing more regulatory immune system cells in the gut that

help control allergies, Blaser said. Those same cells may help

children withstand exposure to other antigens that could provoke a

strong immune reaction, he said. The relationship didn't persist in

adults, who were just as likely to develop asthma regardless of H.

pylori infection status.

'Immune System Helper'

''Our hypothesis is the presence of H. pylori helps our immune system

develop normally,'' Blaser said. ''It might be beneficial early in

life and deleterious later in life.''

Asthma is a chronic disease that causes the airways in the lungs to

swell and become inflamed. The sensitive linings on the airway walls

react to irritants, squeezing shut and making it difficult to

breathe. In severe cases, asthma attacks can be deadly. Medication

can help control the disease and relieve pressure in the airways

during an attack. There is no cure.

About 20 million Americans have asthma, including 9 million children,

according to the Centers for Disease Control and Prevention in

Atlanta. The number of affected children has more than doubled since

the 1980s, government figures show.

Blaser and Yu Chen, an assistant professor of epidemiology at New

York University, scoured data from the National Health and Nutrition

Survey, a comprehensive health analysis involving 7,412 volunteers

across the country. They found H. pylori rates were inversely related

to the development of asthma only in children. The association ebbed

as they studied older groups.

J. Pylori Percentage

They also found only 5.4 percent of children born in the 1990s tested

positive for H. pylori, down from 70 percent two decades ago.

The bacterium is typically acquired in the first years of life and

has been present in humans since the initial migration of man out of

Africa almost 60,000 years ago, Blaser said. The decline

is ''astonishing,'' the researchers said, and may have future health

implications.

''The disappearance of an organism that's been in the stomach forever

and is dominant is likely to have consequences,'' he said. ''Maybe

there is some way to package H. pylori to get the good stuff without

the harm. We need to do a lot of research on this question.''

To contact the reporter on this story: Fay Cortez in

Minneapolis at mcortez@...