Altitude and ADHD

A study indicates that the rates of ADHD are lower at higher altitudes.

Recent research has linked the thin air of higher elevations to increased rates of depression and suicide. But a new study shows there's also good news from up in the aspens and pines: The prevalence of attention deficit hyperactivity disorder (ADHD) decreases substantially as altitude increases.

In Utah, for example, an analysis of information from two national health surveys correlated with the average state elevation of 6,100 feet showed that the rate of diagnosed ADHD cases is about 50 percent of states at sea level. In Salt Lake City, whose elevation is about 4,300 feet, diagnosed ADHD prevalence is approximately 38 percent less than at sea level.

One potential reason for the decreased rate of ADHD, University of Utah researchers believe, is higher levels of dopamine produced as a reaction to hypobaric hypoxia -- a condition caused when people breathe air with less oxygen at higher elevations. Decreased dopamine levels are associated with ADHD so when levels of the hormone increase with elevation, the risk for getting the disorder diminishes. There are other potential reasons for the disparities in the rates of the disorder, such as regional inconsistencies in diagnosing ADHD.

The study findings, published in the Journal of Attention Disorders online, have important implications for potentially treating ADHD, according to Douglas G. Kondo, M.D., assistant professor of psychiatry and senior author on the study. "Our previous studies of mood disorders and suicide consistently suggest that hypobaric hypoxia associated with altitude may serve as a kind of environmental stressor," Kondo says. "But these results raise the question of whether, in the case of ADHD, altitude may be a protective factor."

Rebekah Huber, a doctoral candidate in educational psychology at the University of Utah, is the first author. Huber works in the research group of Perry F. Renshaw, M.D., Ph.D., M.B.A., a University of Utah professor of psychiatry, USTAR investigator and a co-author on the study.

Huber, Kondo, Renshaw and their colleagues conducted the study with data from two national health surveys and information on average state elevations taken from NASA's Shuttle Radar Topography Mission and the National Geospatial-Intelligence Agency.

The National Survey on Children's Health contacted 91,642 households in 2007 and found that 73,123 children ages 4-17 had been diagnosed with mild, moderate or severe ADHD by a physician or other health care provider. The 2010 National Survey of Children with Special Healthcare Needs contacted 372,689 households and found that 40,242 children in that age range had been diagnosed with full ADHD.

The researchers correlated the number of cases of diagnosed ADHD with average elevations in the lower 48 states and the District of Columbia as reported by the federal agencies to determine rates of ADHD. From this, they derived data on ADHD rates at sea level and above and found that for every 1-foot increase in elevation, the likelihood of being diagnosed with ADHD by a healthcare provider decreases by .001 percent.

The data showed that North Carolina, whose average elevation is 869 feet above sea level, had the highest percentage of children diagnosed with ADHD -- 15.6 percent. Delaware, Louisiana and Alabama -- all states with an average elevation of less than 1,000 feet -- followed closely behind North Carolina with high percentages of ADHD.

Nevada -- with an average elevation of 5,517 feet above sea level -- had the lowest percentage at 5.6. Utah had one of the lowest rates of ADHD, 6.7 percent. All of the Mountain West states rated well below average for the percentage of children diagnosed with ADHD. The study also took into account other factors -- such as birth weight, ethnicity, and sex (males are more likely to have ADHD) -- that could affect ADHD diagnoses and influence the rate of the disorder in each state.

This study follows research in which Renshaw and colleagues at the University of Utah and in South Korea showed correlations between increased rates of suicide and depression with higher altitudes.

The decrease in ADHD at elevation doesn't mean people need to start moving to the mountains, according to Renshaw. But the research results do have potential implications for treating the disorder.

"To treat ADHD we very often give someone medication that increases dopamine," he says. "Does this mean we should be increasing medications that target dopamine? Parents or patients might want to take this information to their health care providers to discuss it with them."

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Study shows higher altitudes reduce risk of concussion

According to a recent study, playing football at higher altitudes reduces a player's risk of concussion.

A new study on concussions for NFL players during the 2012 and 2013 season reveals that players are 30 percent less likely to sustain concussions when playing at higher altitudes. The data also suggests that helmet designs and rule changes, such as penal

A new study on concussions for NFL players during the 2012 and 2013 season reveals that players are 30 percent less likely to sustain concussions when playing at higher altitudes. The data also suggests that helmet designs and rule changes, such as penalizing helmet-to-helmet contact, have not shown a measurable reduction of concussions

The study identified “brain slosh” as the suspected common cause of concussions, not direct impact to the head. Because the brain doesn’t fit tightly inside the skull, rapid acceleration and deceleration of the head puts the brain at risk for a slosh-induced injury. This is why higher altitudes may help protect a player. Cerebral blood flow rises at higher altitudes, causing the brain to fit tighter inside the skull, thus reducing the risk of concussion.  It’s like bubble wrapping the brain.

The study concludes that the risk of sustaining a concussion is significantly less at games played in the nine NFL cities with the highest altitudes, cities that range from 644 to 5,192 feet above sea level. These cities include:

The combined odds of concussion during a game in one of these cities was 30 percent less than in the 23 other cities with NFL teams.

“If we’re going to solve this problem, we have to figure out a way to protect the brain from the inside out.  That’s why we think we might be on the front edge of something that could influence a paradigm shift in concussion prevention-strategies,” said Greg Myer, PhD, director of sports medicine research at Cincinnati Children’s Hospital Medical Center. Myer was the lead author of the study.

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Less concussions occur at higher altitudes in high school sports

An interesting study claims that the likelihood of a concussion in high school sports is lower at higher altitudes.

According to a recent study done by doctors at Cincinnati Children's Hospital Medical Center, high school athletes who play collision sports at higher altitudes are less likely to suffer from concussions than those who play at lower altitudes.

The doctors who were involved in the study recognized that prior research indicated that the volume and/or pressure of intracranial fluid, which acts as a cushion to protect the brain inside of the skull, is affected by one's altitude and that it may be associated with the likelihood and/or severity of a concussion. They hypothesized that when adjusting to higher altitudes, physiological responses increase intracranial fluid volume and these responses would provide a "tightened fit" which should help protect the brain from concussions like bubble wrap.

Data on concussions and more than 20 million athlete exposures were gathered between 2005 -2012 from nearly 500 high schools across the US. The data focused on concussion occurrence in a variety of sports including but not limited to boys' and girls' soccer, volleyball, basketball, cheerleading and boys' football and ice hockey. The altitude of the participating schools ranged from 7 to 6903 ft.

When concussion rates were examined relative to altitude, sequential elevations in altitude above sea level were associated with a reduction in concussion rates overall. Specifically, high school sports played at higher altitudes demonstrated a 31 percent reduction in the incidence of total reported concussions. Further analysis showed that concussion rates at increased altitude for football players were reduced by 30 percent for overall exposures, 27 percent for competition exposures and 28 percent for practice exposures.

Dr. Greg Myer, Director of Research, Sports Medicine, Cincinnati Children's Hospital Medical Center, says that "this research shows us that the physiological responses to altitude may be associated with a reduction in sports-related concussion rates, especially in collision sports."

He goes on to say that future research that focuses on other techniques that can optimize intracranial fluid volume (via jugular compression) will play an important role in the determination of the most effective approaches to prevent sport related concussion in athletes.

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