US-born Mexican Americans are at least twice as likely to develop asthma, compared with individuals born in Mexico, according to findings reported in the American Journal of Respiratory and Critical Care Medicine (January 15, 2005). For the study, researchers from the Centers for Disease Control and Prevention examined data from >17,000 Mexican Americans who participated in the Third National Health and Nutrition Examination Survey (NHANES III) or the National Health Interview Survey (NHIS).
The findings from both surveys indicated that the rate of asthma among Mexican Americans born in the United States was about 7.5%, compared with 2.7% of Mexican-born peers. Further investigation showed that US origin doubled the risk of asthma in NHANES III and tripled the risk in NHIS, compared with Mexican origin. The researchers also discovered that the rate of asthma among Mexican-born participants increased in step with the length of time they resided in the United States.