Obese children and teens are 26 per cent more likely than kids of a normal weight to have some kind of allergy, especially a food allergy, U.S. researchers report.
But it is not yet clear if obesity actually causes allergies; only an "association" between obesity and allergies was found, said Dr. Darryl Zeldin, the senior author on the paper.
"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.
Nevertheless, the authors suggest that controlling obesity in young people may be important for lowering rates of allergies.
The researchers, from the National Institute of Environmental Health Sciences, a part of the U.S. National Institutes for Health, analyzed data on 4,111 children aged 2 to 19 that included information about allergies and asthma.
They looked at a number of factors including body weight and BMI (body mass index), antibody levels to indoor, outdoor and food allergens, and responses to a questionnaire about diagnoses of hay fever, eczema, and allergies.
They found that antibodies for specific allergens were higher among children who were obese or overweight.
"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 Dr. Stephanie London, a researcher at NIEHS.
The study appears in the Journal of Allergy and Clinical Immunology.
The study is the first to be published using new data from the National Health and Nutrition Examination Survey (NHANES). NHANES is a large survey designed to assess the health and nutritional status of American adults and children.
An allergy/asthma component was added to the 2005-2006 NHANES study, making it the largest nationally representative dataset of allergy and asthma information ever assembled in the U.S.
"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," said Zeldin.
