( TIME.com ) -- With pollen and other spring allergens in the air , researchers investigated whether place of birth affected the risk of developing allergies , and the answer turns out to be — yes . Having an allergic reaction — with its sneezing , wheezing , itchy eyes and runny nose — is an all too familiar experience for many Americans , particularly children . About 11 % of youngsters suffer from asthma , and up to 20 % may experience some immune-based reaction to allergens such as pollen , dust , animal hair and even foods . But this relatively high prevalence seems to be unique to the United States , so researchers delved into whether different environmental exposures , dictated by where children were born , could affect risk of allergic disease . Reporting in JAMA Pediatrics , the scientists studied 91,642 kids between the ages 0 to 17 , all currently living in the United States , who participated in the 2007- 2008 National Survey of Children 's Health . The children or their parents answered questions about where they were born , and if they were born outside of the country , they were asked to note how long they had lived in the United States . The researchers also collected medical information about the children 's allergic diseases , including asthma , eczema , hay fever and food allergies . TIME.com : Bullying over food allergies . When they compared place of birth with allergic-disease prevalence , the scientists found that children born outside of the United States were less likely to develop asthma or allergies compared with those born in the United States : 20 % of foreign-born kids developed allergic diseases compared with 34 % of the American-born children . The prevalence of asthma was even lower , with those born outside of the country 47 % less likely to develop the condition than those born in the United States . Even after the researchers accounted for factors that could affect rates of allergies , such as race or ethnicity and socioeconomic status , the strong association between being born in the United States and the higher risk of allergic diseases remained . TIME.com : Why we 're going nuts over nut allergies . In fact , it was clear that the U.S. environment played some role in the trend , since foreign-born children who had lived in America for more than 10 years were three times as likely to develop allergic diseases as those who spent less than two years Stateside . And foreign-born children whose parents were also born outside of the United States seemed to benefit from additional protection from these conditions : 18 % of these children developed allergic disease compared with 33 % of foreign-born children whose parents were born in the United States . The results confirm those of previous studies that found higher rates of asthma among American children compared with kids from other countries , and investigators have also reported similar differences in allergic diseases between immigrants and native-born citizens in Italy , Israel and Australia . What does birthplace have to do with how the immune-system functions ? The most likely explanation could involve the `` hygiene hypothesis , '' which suggests that improved sanitation methods and efforts to keep germs at bay may deprive young , still-developing immune systems from being trained to recognize and react appropriately to the right types of irritants . `` The hygiene hypothesis suggests that early-life exposures to infection or an unclean environment may protect against allergies . Children born and raised outside the U.S. likely have more and/or different infectious exposures than those born in the U.S. , '' says study author Dr. Jonathan Silverberg of St. Luke's-Roosevelt Hospital Center in New York . `` That American cities are 'too clean ' may be overstated . However , previous studies suggest that rolling in the dirt from time to time may be a good thing for kids . '' TIME.com : Why kids with known food allergies are still at risk . Parental behaviors and cultural practices may also play a role . `` Parents born and raised outside the United States may , for example , follow a healthier diet or have foods with a different antigenic profile than typically encountered in the Western diet , '' the authors write . `` Some cultures more commonly use spices , such as curcumin , and green tea that have antiallergy and inflammatory properties . '' Such factors could explain why having foreign-born parents seemed to lower risk of allergic disease in their children even further ; the finding held even after the researchers accounted for differences in race , ethnicity , socioeconomic status , and whether or not the child lived in a metropolitan area . Sneezing and wheezing solutions : Surprising ways to relieve spring allergies . In terms of what features of the American lifestyle or culture could be contributing to an increased risk of these diseases , previous studies from the same team of scientists suggested that factors such as climate , obesity , the Western diet and various types of infections could play a role . The current study was n't designed to identify which specific environmental factors might be the most influential , but Silverberg says , `` one of our goals is to determine which factor [ or factors ] have the greatest impact on allergic disease , and to help develop public-health interventions to decrease rates of allergic disease in the U.S. '' — because those influences would likely be far easier to change than where you 're born . This story originally published on TIME.com : . Location , location : Being born in the U.S. puts kids at higher risk of allergies . & copy 2012 TIME , Inc. TIME is a registered trademark of Time Inc. Used with permission .
The U.S. economy seems to play some role in the health problem . ' Hygiene hypothesis ' may have something to do with it . Parental health and cultural practices may also play a role .