Food allergies affect children regardless of geography but it may occur more often in one location versus another. In a new study, city kids were more likely to have food allergies than their rural counterparts.

Food allergies were more common in American children who lived in the city compared to children who lived in a rural environment. This discovery could help shed light on why children develop food allergies and the role a child's environment could play in its development.

The study was led by Dr. Ruchi Gupta, assistant professor of pediatrics at Northwestern University Feinberg School of Medicine. Researchers observed a nationally-representative group of 38,465 children under the age of 18. Food allergies were mapped by using ZIP codes. While city kids were more likely to have food allergies, kids in big cities were twice as likely to have food allergies as kids living in a rural environment.

The states with highest number of children affected by food allergies were Nevada, Florida, Georgia, Alaska, New Jersey, Delaware, Maryland and the District of Columbia.

Food allergies affected 9.8 percent of city kids while 6.2 percent of kids from rural communities had food allergies. Peanut allergies were twice as common in city kids as kids from rural communities, 2.8 percent versus 1.3 percent respectively.

The disparity was greatest for children with Shellfish allergies. For city kids, shellfish allergies affected 2.4 percent of the population while only affecting 0.8 percent of children from rural communities.

Food allergies were serious concern, regardless of location. Of the children who participated, approximately 40 percent had a life-threatening reaction due to food allergies.

The study is more than just comparing two groups of individuals based on geography as nearly 5.9 million children are affected by food allergies, according to researchers. According to the American College of Allergy, Asthma and Immunology, food allergy symptoms could include itchiness of the mouth, hives, swelling of the lips, vomiting, headaches, asthma, difficulty breathing and even anaphylactic shock.

Researchers believe the environment may play a role in the development of food allergies. Asthma, eczema, allergic rhinitis, or hay fever when caused by grass pollens and pink eye are also more common in city kids. The reason for this disparity could be exposure to bacteria in rural communities which could boost allergy immunity or the exposure to a vast array of pollutants for city kids. Future studies could focus on studying the environment's effect on allergies.

The study will be published in the July edition of Clinical Pediatrics.