Monday, May 4, 2009, 12:00 p.m. EDT
A new study indicates there may be yet another reason to reduce childhood obesity — it may help prevent allergies. The study published in the May issue of the Journal of Allergy and Clinical Immunology showed that obese children and adolescents are at increased risk of having some kind of allergy, especially to a food. The study was funded by the National Institute of Environmental Health Sciences (NIEHS) and the National Institute of Allergy and Infectious Diseases (NIAID), both parts of the National Institutes of Health.
"We found a positive association between obesity and allergies," said Darryl Zeldin, M.D., acting clinical director at NIEHS and senior author on the paper. The researchers analyzed data on children and young adults ages 2 to 19 from a new national dataset designed to obtain information about allergies and asthma. "While the results from this study are interesting, they do not prove that obesity causes allergies. More research is needed to further investigate this potential link," Zeldin said.
The study is the first to be published using new data from the National Health and Nutrition Examination Survey (NHANES). NHANES is a large nationally representative survey conducted by the National Center for Health Statistics, a part of the Centers for Disease Control and Prevention. NHANES is designed to assess the health and nutritional status of adults and children in the United States. An allergy/asthma component was supported by NIEHS and added to the 2005-2006 NHANES study, making it the largest nationally representative dataset of allergy and asthma information ever assembled in the United States.
"We have all the pieces of the puzzle in this dataset," said Zeldin. "The allergy and asthma component of NHANES provides allergen exposure information, allergic sensitization information, as well as disease outcome information. There is a wealth of knowledge we will be able to gain by analyzing these data that will be useful to allergy and asthma sufferers."
In this study, the researchers analyzed data from 4,111 children and young adults aged 2-19 years of age. They looked at total and allergen-specific immunoglobulin E (IgE) or antibody levels to a large panel of indoor, outdoor and food allergens, body weight, and responses to a questionnaire about diagnoses of hay fever, eczema, and allergies. Obesity was defined as being in the 95th percentile of the body mass index for the child's age. The researchers found the IgE levels were higher among children who were obese or overweight. Obese children were about 26 percent more likely to have allergies than children of normal weight.
"The signal for allergies seemed to be coming mostly from food allergies. The rate of having a food allergy was 59 percent higher for obese children," said NIEHS researcher Stephanie London, M.D., a co-author on the study.
"As childhood obesity rates rise, NIEHS will continue to work to determine how environmental factors affect this epidemic," said Linda Birnbaum, Ph.D., NIEHS director. "Seeing a possible link between obesity and allergies provides additional motivation for undertaking the challenge of reducing childhood obesity."
"Given that the prevalence of both obesity and allergic disease has increased among children over the last several decades, it is important to understand and, if possible, prevent these epidemics," said Cynthia M. Visness, Ph.D., lead author on the paper and a scientist at Rho Federal Systems Division, Inc. in Chapel Hill, N.C.
NIAID conducts and supports research — at NIH, throughout the United States, and worldwide — to study the causes of infectious and immune-mediated diseases, and to develop better means of preventing, diagnosing and treating these illnesses. News releases, fact sheets and other NIAID-related materials are available on the NIAID Web site at http://www.niaid.nih.gov/.
Reference: Visness CM, London SJ, Daniels JL, Kaufman JS, Yeatts KB, Siega-Riz AM, Liu AH, Calatroni A, Zeldin DC. Association of obesity with IgE levels and allergy symptoms in children and adolescents: Results from the National Health and Nutrition Examination Survey 2005-2006. Journal of Allergy and Clinical Immunology. May, 2009. Doi:10.1016/j.jaci.2008.12.1126.
About the National Institute of Environmental Health Sciences (NIEHS): NIEHS supports research to understand the effects of the environment on human health and is part of the National Institutes of Health. For more information on NIEHS or environmental health topics, visit www.niehs.nih.gov or subscribe to a news list.
About the National Institutes of Health (NIH): NIH, the nation's medical research agency, includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. NIH is the primary federal agency conducting and supporting basic, clinical, and translational medical research, and is investigating the causes, treatments, and cures for both common and rare diseases. For more information about NIH and its programs, visit www.nih.gov.
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