Just 17% of children who had lived in the United States for up to 2 years had asthma or allergies, compared with 27% of those who had lived in the country for 10 years or longer.
Children who live in the United States but were born abroad are less likely to develop asthma and allergies than those born in the United States, according to the results of a study published online on April 29, 2013, in JAMA Pediatrics
The researchers surveyed parents of more than 80,000 children up to age 17 and looked for connections between birthplace, place of residence, and likelihood of developing asthma and allergies.
Children born outside the United States had significantly lower odds of having asthma, eczema, hay fever, and food allergies than those born in the country. Slightly more than 20% of foreign-born children had any type of allergic disease compared with 34% of American-born children.
The researchers also found that the longer children born abroad had lived in the United States, the more likely they were to develop allergies.
Only 17% of children who had lived in the country for up to 2 years had an allergic disease compared with 27% of children who had lived in the United States for 10 years or longer.
“The results of the study suggest that there are environmental factors in the US that trigger allergic disease,” lead researcher Jonathan Silverberg, MD, PhD, MPH, of Beth Israel Medical Center and St. Luke’s-Roosevelt Hospital Center in New York told Reuters. “Children born outside the US are likely not exposed to these factors early in life and are therefore less likely to develop allergic diseases.”