It looks like we are predisposed to allergies, no matter where we live.
In the largest, most comprehensive study to examine the prevalence of allergies in people from early childhood to old age, scientists have reported that allergy prevalence is the same across different regions of the United States. The exception is for children 5 years old and younger.
“Before this study, if you would have asked 10 allergy specialists if allergy prevalence varied depending on where people live, all 10 of them would have said yes, because allergen exposures tend to be more common in certain regions of the U.S.,” explained Darryl Zeldin, M.D., scientific director of the National Institute of Environmental Health Sciences, part of the NIH. “This study suggests that people prone to developing allergies are going to develop an allergy to whatever is in their environment. It’s what people become allergic to that differs.” The research is based on blood serum data from 10,000 Americans from all over the U.S.
Among children aged one to five, those in the southern U.S. showed a higher rate of allergies than their peers living elsewhere. Those states include Texas, Oklahoma, Louisiana, Arkansas, Tennessee, Kentucky, Mississippi, Alabama, Georgia, West Virginia, Virginia, North Carolina, South Carolina and Florida.
Reasons for Difference
“The higher allergy prevalence among the youngest children in southern states seemed to be attributable to dust mites and cockroaches,” noted Paivi Salo, PhD, an epidemiologist in Zeldin’s research group and lead author on the paper. “As children get older, both indoor and outdoor allergies become more common, and the difference in the overall prevalence of allergies fades away.”
Sensitivities to indoor allergens were more pronounced in the South, while sensitivity to outdoor allergens was more common in the western areas of the ccountry. Food allergies for children 6 years and older were highest in the South.