Respiratory infections may explain antibiotic link to allergic disease
MedWire News: The link between antibiotic use in early life and the development of allergic disease may be partly explained by respiratory infections, say researchers.
"Early antibiotic use has been postulated to increase the development of allergic disease due to its disturbance of intestinal microflora and the subsequent influence on the developing immune system towards T-helper 2 immune responses," explain Xiao-Mei Mai (Norwegian University of Science and Technology, Trondheim) and colleagues.
However, they add that early respiratory infections, which are often treated with antibiotics, have been shown to increase the risk for asthma and allergies, and may therefore play a significant confounding role in the proposed link between antibiotics and allergic disease.
To investigate, the researchers studied a Swedish birth cohort of 3306 children who were followed-up at the ages of 1, 4, and 8 years.
Data on antibiotic use and respiratory infections in the first year of life were compared with information on allergic diseases at 4 and 8 years of age.
In total, 1420 (43%) children received antibiotics and 1046 (32%) suffered at least one type of respiratory infection, such as pneumonia or bronchitis, during the first year of life.
At the age of 4 years, 15% of children had wheeze, 7% had asthma, 11% had allergic rhinitis, 20% had eczema, and 12% had food hypersensitivity, while the proportions of children who had these conditions at the age of 8 years were 10%, 6%, 14%, 16%, and 13%, respectively.
After adjustment for gender, young maternal age, number of older siblings, maternal smoking, parental allergy, and exclusive breastfeeding, initial analysis indicated that antibiotic use during the first year of life was significantly associated with wheeze, asthma, eczema, and food hypersensitivity at 4 years of age.
However, after further adjustment for respiratory infections during the first year of life, only the associations with wheeze and asthma at the age of 4 years remained significant, at odds ratios (ORs) of 1.2 and 1.4, respectively.
In a subgroup analysis of children without early allergic signs, these associations became nonsignificant.
There were no significant associations between early antibiotic use and allergic conditions at the age of 8 years, after adjustment for early respiratory infections and other factors.
Mai and team conclude in the journal Clinical and Experimental Allergy: "Our study indicated that the association between antibiotic use during the first year of life and development of allergic disease could at least partially be explained by respiratory infection during the first year of life."
They add: "Although they may not be the cause for the development of allergic disease, antibiotics should still be prescribed to children in a sensible way to reduce the increased problem of antibiotic resistance."
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By Mark Cowen