BEIJING, July 16 (Xinhuanet) -- A bacteria that is a major cause of stomach cancer and ulcers may help shield children from asthma, U.S. researchers reported Tuesday.

    Children infected with the bacteria, called Helicobacter pylori, were much less likely to have asthma than uninfected children, they reported.

    "Our findings suggest that absence of H. pylori may be one explanation for the increased risk of childhood asthma," said Yu Chen, assistant professor of epidemiology at New York University School of Medicine, who worked on the study. "Among teens and children ages 3 to 19 years, carriers of H. pylori were 25 percent less likely to have asthma."

    Children aged 3 to 13 were 59 percent less likely to have asthma if they also had H. pylori, they reported in the journal Clinical Infectious Diseases.

    The researchers used data on more than 7,000 U.S. children from the National Health and Nutrition Survey conducted from 1999 to 2000 by the National Center for Health Statistics.

    The study showed that 5.4 percent of children born in the 1990s tested positive for H. pylori.

    "If you look at the people born in 1919, 60 percent are positive. That's a huge change," Blaser said in a telephone interview. "I have referred to this as global warming of the stomach."

    During the same time, asthma rates have soared. Among the children aged 3 to 19 in the study, 23 percent had asthma, Blaser said.

    (Agencies)