Even after adjusting for traditional risk factors such as age, race, household income, population density, and gender, the authors found that suicide rates (whether involving a firearm or not) were significantly higher than average in those counties with higher altitudes.
Even after adjusting for greater isolation, lower income and greater access to firearms, the findings remained statistically significant, the authors said.
In contrast, those same locales defined by relatively high topography were not home to the highest rates of death due to any and all causes. In fact, higher altitude counties actually registered lower than average death rates due to all causes.
This latter finding actually highlighted the strength of the apparent connection between suicide risk and high altitudes, the research team said.
For the time being, Brenner and his colleagues cautioned that attempts to explain the association are "speculative."
"It may be related to obesity levels and sleep apnea that may be more common in higher altitudes," Brenner suggested. He and his colleagues also noted that hypoxia -- inadequate oxygen supply to the body's cells and tissues -- is more common at high altitudes, and is thought to increase mood disturbances, especially among emotionally unstable patients.
"It could be that hypoxic environments may lead to higher levels of depression or higher tendencies among the depressed to take suicidal action," he said. "It's an area that is rife for further investigation."
Meanwhile, the research team suggested that their findings might help draw attention to residents of higher elevations who could benefit from relocation to lower altitudes and/or suicide monitoring and prevention services.
Last fall, Dr. Perry F. Renshaw, a professor of psychiatry at the Utah School of Medicine and
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