For the first time, researchers have studied rates of food allergies in the United States by giving allergy tests, rather than asking people about their allergies. The study, published in The Journal of Allergy and Clinical Immunology involved researchers taking blood samples from over 8,000 people and testing them for four allergies: peanut, cow's milk, egg white, and shrimp. The results have implications for health policy and the need for education about food allergies and asthma.
From this sample of tests, they estimate that 2.5%, or about 7.8 million people in the U.S. have food allergies. They estimate that 4.2% of children age 1 through 5 have food allergies. This estimate is very close to that of a study published in the journal Pediatrics, which asked parents to report on their children's allergies, and found that 3.9% of children had reported food allergies.
Food allergies have a disproportionate impact on African-Americans and people living in poverty. Non-Hispanic African-Americans (5.9%) had the highest rate of allergies of any ethnic group. Low-income people (2.9%) were more likely to have food allergies than the wealthy (2.1%). African-American boys were 4.4 times more likely to have food allergies than the rest of the population.
The study also found that people with asthma were more likely to have food allergies. And those people who had both asthma and food allergies were more likely to have had an emergency room visit for an asthma attack in the past year. If you have asthma and food allergies, you may be at a higher risk for having a severe asthma attack. Talk to your doctor about managing your asthma and your food allergies.
This study raises as many questions as it answers. Some of mine are:
- The study only tested for the presence of four allergies, while people can be allergic to basically anything. Is the real rate of food allergies in the U.S. much higher than 2.5%? Could the actual rate of allergies higher than the self-reported rate, indicating that there are a lot of undiagnosed people out there?
- 44 million people lived below the poverty line in 2009. A quick calculation shows that an estimated 1.3 million people living in poverty have food allergies - many of whom are living without health insurance. How can we assure they get adequate preventive care?
- We need to understand why the rates of food allergies in the under-5 set are so much higher than for adults. Are children aging out of their allergies, or are there more children with food allergies than there used to be?
- Why do African-American boys have a so much higher rate of food allergies than the rest of the population? How can we close the gap?
Branum AM, Lukacs SL. Food allergy among children in the United States. Pediatrics. 2009;124:1549-55.
Liu,A, et al. National prevalence and risk factors for food allergy and relationship to asthma: Results from the National Health and Nutrition Examination Survey 2005-2006 The Journal of Allergy and Clinical Immunology. Volume 126, Issue 4, October 2010
Morello, Carol. About 44 million in U.S. lived below poverty line in 2009, census data show. Washington Post. Accessed 10/20/2010.
U.S. Census Bureau. http://www.census.gov/ Accessed 10/20/2010