Early results from the largest cross-sectional national allergy study ever conducted, to be released later this month, demonstrate that food allergies commonly occur in infants and toddlers, while environmental allergies, such as to dust, ragweed, and mold, are more common in older children and adults. The study, based on laboratory testing from more than 2 million patient visits in the US, is the largest to reveal a pattern of allergen sensitivity consistent with the "allergy march," a medical condition by which allergies to foods in early childhood heighten the risk for the development of additional and more severe allergy-related conditions, including asthma, later in life.
The Quest Diagnostics Health Trends Report, Allergies Across America™, from Quest Diagnostics, also found that patients with asthma who were tested for allergies were 20% more likely to have an allergy, particularly to indoor allergens like mold and house dust mites, compared to patients tested without asthma, based on an analysis of test results showing immunoglobulin E (IgE) sensitivity to certain allergens. The findings support medical guidelines recommending that clinicians and patients with asthma identify and minimize potential allergens in the home and workplace that could aggravate the disease.
"Allergy and asthma often go hand in hand, and the development of asthma is often linked to allergies in childhood via the allergy march," said study investigator Harvey W. Kaufman, MD, senior medical director, Quest Diagnostics. "Given the growing incidence of asthma in the US, our study underscores the need for clinicians to evaluate and treat patients, particularly young children, suspected of having food allergies in order to minimize the prospect that more severe allergic conditions and asthma will develop with age. It also demonstrates that patients with asthma should minimize their exposure to allergens that could trigger a severe asthma response."
Allergies are one of the most common health conditions, affecting one in five Americans. A report out this month from the US Centers for Disease Control and Prevention shows the prevalence of asthma is increasing, and now affects one in 12 adults and nearly one in 10 children. Allergy-induced asthma is the most common type of asthma in the U.S.
The Quest Diagnostics study found that children through the age of eight who were tested were most likely to experience high food allergy rates. Specifically, the study’s childhood food allergy analysis found 37% of infants and toddlers tested were sensitive to egg white and 36% of three year olds were sensitive to milk; peanuts were the most common source of food allergy in children six to 18 years of age, affecting approximately one in four (26 %) school-aged children tested; and nearly one in four (23%) children tested through the age of 10 exhibited wheat allergen sensitization, although the rate declined after that age.
After the age of eight, rates of food allergies overall declined, while sensitivity to non-food allergens increased, consistent with the allergy march. Sensitivity to environmental allergens, including house dust mites, cats, dogs, and common ragweed, remained at high levels through the age of 40.