(RxWiki News) If you move from the city to the country, your child may have fewer classmates with peanut allergies. But if you do the reverse, chances are more classmates will have food allergies.
Where kids live seems to matter when it comes to their food allergies, according to a recent study that mapped out frequency of allergies by geographical location.
"Take a child to a doctor immediately with any allergic reaction."
Lead author Ruchi Gupta, MD, an assistant professor of pediatrics at Northwestern University Feinberg School of Medicine and a doctor at Chicago's Ann & Robert H. Lurie Children's Hospital, mapped out the food allergy prevalence of 38,465 children by ZIP code.
The children were all under age 18 and together represented the demographics of the US. Their geographical location was coded as an urban center, metropolitan city, urban outskirts, suburban areas, small towns or rural areas.
Dr. Gupta's team found that 9.8 percent of children in the urban center group have food allergies compared to 6.2 percent of children in rural areas.
The states with the highest rates of food allergies among children included Nevada, Florida, Georgia, Alaska, New Jersey, Delaware, Maryland and Washington, DC.
Peanut and shellfish allergies, in particular, are more than twice as high in urban centers than in rural areas. While 2.8 percent of city kids have peanut allergies, only 1.3 percent of country kids did.
The gap was even more dramatic for shellfish: 2.4 percent of urban children compared to 0.8 percent of rural kids.
"This shows that environment has an impact on developing food allergies," Dr. Gupta said. "Similar trends have been seen for related conditions like asthma. The big question is – what in the environment is triggering them? A better understanding of environmental factors will help us with prevention efforts."
In making their calculations, the researchers controlled for gender, age, race/ethnicity and household income.
The severity of the allergies didn't seem to matter according to where the child lived, and almost 40 percent of the children in the study who had food allergies had experienced a life-threatening reaction already.
Dr. Gupta's background research mentioned that about 5.9 million children - 1 in every 13 - have a food allergy, and untreated reactions can be fatal. A reaction might include a severe drop in blood pressure, difficulty breathing and a swollen throat.
The study was published in the July issue of Clinical Pediatrics. The research was funded by the Food Allergy Initiative.