Food Allergy among Children in the United States – Article Review
Food Allergy among Children in the United States
Authors: Amy Branum and Susan Lukacs
Reference: Pediatrics Volume 124 (6) December 2009
This title caught my eye. The impression in clinical practice is that more and more children have food allergy. This article looks at the prevalence of food allergy in children. I wanted to get this review posted this week. I am off to Santa Fe to moderate an AAP Practical Pediatrics Course. This AAP meeting is similar to the one I reported on earlier on this home page (Rhode Island). This meeting has an excellent cast of presenters. I plan to take notes and post a few updates upon my return.
Purpose of the article: To describe trends in the prevalence of food allergy and food allergy-related health care utilization in children in the United States.
Methods (how was this study conducted?): Data from a number of national health surveys were reviewed.
- Food allergy prevalence was evaluated in children 0-17 years of age from surveys conducted over the years 1997-2007. The question asked about food allergy was “During the past 12 months has the child had any kind of food or digestive allergy?”
- Blood tests for IgE antibodies to foods were taken from the National Health and Nutrition Examination Survey (NHANES) 2005-2006. Specific IgE antibodies to peanut, egg, and milk were measured using the Pharmacia ImmunoCap 1000 System. Specific IgE to shrimp was measured only in children over the age of 6 years. The range of specific IgE values was 0.35 to 1000 kU/L.
- Information regarding food allergy-related visits to physician offices and hospital facilities was taken from two additional surveys.
- The results were analyzed using rather sophisticated statistical tools that included weighing the data for the analysis of trends.
Results (what the study found):
- The prevalence of reports of food allergy in children has increased from 3.3% in 1997 to 3.9% in 2007.
- Peanut IgE antibodies were found in 9.3%, egg IgE antibodies were found in 6.7%, milk IgE antibodies in 12.2%, and shrimp specific IgE was found in 5.2% of children.
- Ambulatory care visits for food allergies tripled between 1993 and 2006. Between the years 2003 and 2006 there were 317,000 visits/years to emergency departments and outpatient offices. Hospitalizations with a recorded diagnosis related to food allergy increased from 2600 to 9500 discharges/year.
Conclusions:
These national surveys show that food allergy prevalence and/or food allergy awareness has increased in recent years.
Commentary:
The authors point out a number of limitations in the study, however the major contribution here is reporting on what these surveys reveal about the parent’s report regarding food allergy. Food allergy may be rising however it is possible that the results may be due to increased food allergy awareness which is also a very good thing. This is a report of prevalence and does not go into the possible reasons for the increases.
It is important to note that this was a survey. A simple question was asked. These were not absolutely proven cases of food allergy. The question included digestive allergy which has the potential to include a number of clinical conditions that are more common and may or may not be allergy; lactose intolerance, eosinophilic esophagitis, and celiac disease for example. This was a report on what a parent thought about food allergy in their child.
The report has a few ‘between the lines’ issues as well. The conclusion is that food allergy and digestive tract allergy has a prevalence of 3.9%. The study also included a survey in which a blood test for allergy was performed. Using the blood test the prevalence of peanut, egg, milk, and shrimp ‘allergy’ exceeds the overall food allergy prevalence. The authors do point out this difference and are very careful about what is allergy and what sensitization to food is. “Although serum IgE measurements cannot be used alone to determine the prevalence of food-specific allergies or to predict reactions to certain foods, they give an indication of increased atopy and risk for allergic reactions to food.” I define allergy and atopy on my allergy testing page.
We also need to be a bit careful on the hospital data. The information on health care utilization included children who had a diagnosis of a food allergy. This did not necessarily mean that they were in the health care facility for a food allergy issue. There is a tendency in coding encounters to include as many codes as possible and to include codes that will help with health care utilization reimbursements.
The statistical analyses on papers like this always fascinate me. During my MPH training I had a number of biostatistics courses. The weighing of the data is frequently done and when it is done, differences can be found. Sometimes it is interesting to see what the results were before any weighing. I have also wondered what went into the ‘weighing’ of the data. What elements of the data were assigned a ‘weight’ to make them work into the analysis?
This was a nicely done paper and does answer some questions however as many quality studies also do it has us asking many more questions about food allergy in children.
Fred Leickly
December 1, 2009
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fleickly · 
4 Comments
Tags: Article Review, Food Allergies, Food Allergy Epidemiology · Posted in: Allergies, Allergy Testing, Food Allergies
4 Responses
i also have lactose intolerance that is why i always avoid dairy products.,..
Your lactose intolerance would be an adverse reaction to a food, however a ‘metabolic’ reaction and not an allergic, type I- IgE mediated response. In lactose deficiency the enzymes that metabolize the milk sugar, lactose, are gone or severely compromised. The complex milk surgar is not broken down into two simple sugars and the bacteria in the gut do nasty things when they see lactose.
Thank for your comment
FEL
well we do have some lactose intolerance in our family and we just cut out on dairy products. -,’
Now lactose intolerance is an example of an “adverse reaction” to a food, however it is not an allergic reaction. The milk protein (lactose) needs an enzyme (lactase) to cleave the sugar. When this enzyme is out, lactose is not digested properly. The treatment for this is to avoid lactose (cut it out as you mention) or some will add enzyme to the food.
Thanks for your comment,
FEL
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