ピロリ菌 Helicobacter pylori が子どもの喘息の発症率を50%以上減らす。|
Stomach Germ May Protect Against Asthma
Disappearance of H. pylori could leave kids more susceptible to the disease, study says
By Steven Reinberg, HealthDay Reporter
Disappearance of H. pylori could leave kids more susceptible to the disease, study says.
TUESDAY, July 15 (HealthDay News) -- A stomach bacterium called Helicobacter pylori may reduce a child's risk of developing asthma by as much as 50 percent, a new study suggests.
H. pylori has been present in the human stomach probably since humans were humans. However, the germ began disappearing over the course of the 20th century with the introduction of antibiotics and cleaner water and homes, perhaps making children more susceptible to asthma, the study authors suggested.
"In our study we asked the question, is there any relationship between having H. pylori in the stomach and having asthma and other allergic disorders," said lead researcher Dr. Martin J. Blaser, the Frederick H. King Professor of Internal Medicine and chairman of the department of medicine at the New York University Langone Medical Center in New York City.
"We found a strong inverse association between H. pylori and childhood asthma, childhood hay fever and childhood allergies," added Blaser, who's also a professor of microbiology and has studied H. pylori for more than two decades.
Blaser thinks that H. pylori may protect the body against asthma. "When children have H. pylori in their stomach, their immune system is different than if they don't have H. pylori," he said.
H. pylori has been disappearing especially since World War II, which is when the incidence of asthma began increasing, Blaser said.
For the study, Blaser and his colleague Yu Chen, an assistant professor of epidemiology, collected data on 7,412 children who participated in the 1999 to 2000 National Health and Nutrition Examination Survey IV, conducted by the National Center for Health Statistics.
Among children in the survey, just 5.4 percent born in the 1990s tested positive for H. pylori. In addition, 11.3 percent of the children under 10 had taken antibiotics in the month before the survey.
Blaser and Chen found that among children 3 to 13 years of age, those who carried the stomach bug were 59 percent less likely to develop asthma than children without H. pylori. These children were also 40 percent less likely to suffer from hay fever and other allergies, such as eczema or rash.
Among children aged 3 to 19, the researchers found that those who harbored H. pylori reduced their risk of asthma by 25 percent.
"This is a new way of saying who's at risk for asthma and who's not," Blaser said. "You can't mess with Mother Nature. This bacterium that has been present forever in the human stomach has been disappearing, and that has consequences."
Some of the consequences are good, however, Blaser noted. These include the decline of ulcers and decreases in stomach cancer among adults, he said. "But these are diseases of old age," he said. "It is possible that H. pylori may be protective of children, but bad for old people."
The study findings were published online July 15 in The Journal of Infectious Diseases.
Dr. Clifford Bassett, medical director of Allergy and Asthma Care of New York in New York City, thinks the findings open a new window on doctors' understanding of asthma and allergies.
"It appears this will add to our knowledge and research looking at incidence and prevalence of asthma and allergic diseases in children and adults in an increasingly sanitized world," he said. "The relevance of H. pylori as a potential risk in asthma is quite thought-provoking by any means."
For more on asthma, visit the U.S. National Institutes of Health.
SOURCES: Martin J. Blaser, M.D., the Frederick H. King Professor of Internal Medicine, chair, department of medicine, and professor, microbiology, New York University Langone Medical Center, New York City; Clifford Bassett, M.D., fellow, American Academy of Allergy, Asthma and Immunology, and medical director, Allergy and Asthma Care of New York, New York City; July 15, 2008, The Journal of Infectious Diseases, online
Copyright (c) 2008 ScoutNews, LLC. All rights reserved.
The Journal of Infectious Diseases 2008;198:000--000
(c) 2008 by the Infectious Diseases Society of America. All rights reserved.
Helicobacter pylori Colonization Is Inversely Associated with Childhood Asthma
Yu Chen1,2,3 and
Martin J. Blaser3,4,5
Departments of 1Environmental Medicine, 3Medicine, and 4Microbiology, School of Medicine, and 2Cancer Institute, New York University, and 5Department of Veterans Affairs Medical Center, New York, New York
Background. Asthma, a serious health problem worldwide, is becoming more common. Colonization with Helicobacter pylori, a major human indigenous (commensal) microbe, during early life may be relevant to the risk of childhood asthma.
Methods. We conducted cross-sectional analyses, using data from 7412 participants in the National Health and Nutrition Examination Survey (NHANES) 1999--2000, to assess the association between H. pylori and childhood asthma.
Results. H. pylori seropositivity was inversely associated with onset of asthma before 5 years of age and current asthma in children aged 3--13 years. Among participants 3--19 years of age, the presence of H. pylori was inversely related to ever having had asthma (odds ratio [OR], 0.69; 95% confidence interval [CI], 0.45--1.06), and the inverse association with onset of asthma before 5 years of age was stronger (OR, 0.58; 95% CI, 0.38--0.88). Among participants 3--13 years of age, H. pylori positivity was significantly inversely associated with current asthma (OR, 0.41; 95% CI, 0.24--0.69). H. pylori seropositivity also was inversely related to recent wheezing, allergic rhinitis, and dermatitis, eczema, or rash.
Conclusions. This study is the first to report an inverse association between H. pylori seropositivity and asthma in children. The findings indicate new directions for research and asthma prevention.
Received 8 January 2008; accepted 5 March 2008; electronically published 3 July 2008.
Potential conflicts of interest: none reported.
Presented in part: 45th Annual Meeting of the Infectious Diseases Society of America, San Diego, CA, October 2007 (abstract LB-1).
Financial support: National Institute of Environmental Health Sciences (grant ES000260); National Cancer Institute (grant CA016087); National Institutes of Health (grant RO1GM63270); The Diane Belfer Program in Human Microbial Ecology; Ellison Medical Foundation (Senior Scholar Award).
Reprints or correspondence: Dr. Martin J. Blaser, Dept. of Medicine, New York University School of Medicine, 550 First Ave., OBV A-606, New York, NY 10016 (Martin.Blaser@med.nyu.edu).
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