LAWRENCEVILLE -- Doctors call it the "hygiene hypothesis," and a new government study suggests the number of American children who suffer from food and skin allergies has increased dramatically in recent years.
The Centers for Disease Control and Prevention study said the prevalence of food and respiratory allergies rises with income, and children of families who made more than 200 percent of the poverty level had the highest rates of those allergies.
A Lawrenceville doctor said she hasn't personally seen an uptick, but pointed to the hygiene hypothesis.
"In higher income families, they're more likely to be the ones to sterilize the pacifier, and not do the five-second rule," said Dr. Kathleen Sheerin of the Atlanta Allergy & Asthma Clinic, who practices in Lawrenceville. "Germs are good for you. If you lead too clean a life, you may end up more allergic."
Of families who make less than 100 percent of the poverty level, 4.4 percent of those children had food allergies and 14.9 percent had respiratory allergies. But those who make more than 200 percent of poverty level, 5.4 percent of those children had food allergies and 18.3 percent had respiratory allergies.
A co-author of the CDC study, LaJeana Howie, from the U.S. National Center for Health Statistics, said the prevalence of food and skin allergies have both increasd over the last 14 years.
"This has been a consistent trend," Howie said.
Sheerin said the "big seven" food allergies haven't changed in more than 20 years. They are milk, egg, wheat, peanut, tree nut, soy and seafood.
The CDC data suggested differences in race and age with respect to prevalence of allergies. Hispanic children had the lowest prevalence of food, skin and respiratory allergies, while black children were more likely to have skin allergies than white children, but less likely to have respiratory allergies (15.6 percent versus 19.1 percent, respectively).
The older children were the less likely they were to have skin allergies, the study found. Fourteen percent of children 4-years-old and younger had them, while just 10.9 percent of children ages 10 to 17 had skin allergies.