Higher Altitude Linked With Lower Rates of ADHD
Low-lying states have rates up to 16 percent, compared to 6 percent in mountain regions
FRIDAY, April 17, 2015 (HealthDay News) -- The effects of higher altitude may reduce the risk of attention-deficit/hyperactivity disorder (ADHD), a new study suggests. The research was published online March 25 in the Journal of Attention Disorders.
The research team relied on elevation data gathered during a NASA space shuttle mission. This mission created a highly detailed topographical map of the 48 contiguous United States. The investigators then paired that with data on ADHD collected during two surveys conducted by the U.S. Centers for Disease Control and Prevention.
The researchers found that for every one-foot increase in elevation, the likelihood of being diagnosed with ADHD by a health care provider decreased by 0.001 percent. North Carolina, with an average elevation of 869 feet above sea level, had the highest percentage of children diagnosed with ADHD -- nearly 16 percent. Nevada has an average elevation of more than 5,500 feet above sea level, and the lowest percentage of children diagnosed with ADHD (less than 6 percent). Utah also had one of the lowest rates of ADHD, at less than 7 percent, the findings showed. All of the western mountain states rated well below average for the percentage of children diagnosed with ADHD. That was true even after the researchers adjusted the data to control for other factors that could affect ADHD risk, such as birth weight, ethnic background, and gender.
The researchers suspect that brain chemistry may be affected by the lower oxygen levels at higher elevations. In particular, levels of dopamine increase as someone adapts to oxygen-depleted air, study author Douglas Kondo, M.D., a child psychiatrist and brain imaging researcher at the University of Utah's Brain Institute and University Neuropsychiatric Institute in in Salt Lake City, told HealthDay. Kondo and his colleagues have theorized that as dopamine levels increase with elevation, the risk for developing ADHD diminishes.