The curious relationship between altitude and suicide

November 6, 2017 by Hoehun Ha, The Conversation
Does living at a higher altitude affect your mental health? Credit: VAndreas/shutterstock.com

Suicide is one of the top 10 causes of death in the U.S. In the next 20 years, it's expected to cause more than 2 million deaths per year worldwide, ranking 14th in the world as a cause of death.

There are many factors known to affect an individual's risk for . For example, people who are older, male, white, divorced, low-income, isolated or who abuse substances are all at higher risk. Psychiatric illness, mood disorders and lack of are also recognized risk factors.

Several studies have demonstrated geographic variations in suicide patterns in the U.S., with higher suicide rates in western states. Our ongoing research expands on those findings, showing that Americans who live in higher-altitude counties are at a higher risk for suicide.

Altitude and health

Increased elevation has been known to have a protective relationship with certain medical illnesses. For example, people who live at higher altitudes are somewhat less likely to die from coronary artery disease or stroke. But increased elevation may also enhance psychological problems, such as panic attacks.

Previous studies have reported a significant association between suicide and altitude. One study showed a strong positive relationship between average state altitude and suicide rate. For example, in Utah, the average geographic altitude is about 6,000 feet, and the rate of suicide is 70 percent higher than average.

Another, similar study showed that higher-altitude states had significantly higher suicide rates than lower-altitude . Similar findings were observed for both firearm-related and nonfirearm-related suicides.

These studies suggest altitude is a significant risk factor for depressive symptoms and suicide. However, average state altitude doesn't provide a very close look at the relationship between suicide and altitude. Altitude could vary widely across the state, so the average may not properly represent the elevation for each place.

Risk across the US

As part of an ongoing project, our lab has examined all 3,064 contiguous U.S. counties with average county elevation to access whether there is a significant association between suicide and altitude.

Looking at average altitude for county, rather than center of county or state, would better represent the elevation for each place. We calculated the average elevation based on the total number of 30-meter by 30-meter grids in each county.

We looked at suicide data from the National Center for Health Statistics for every U.S. county between 2008 and 2014. Calculations for average county latitude came from the U.S. Geologic Survey. Alaska and Hawaii were not included in our analysis, because digital altitude information was not fully available.

We found that, for every increase of 100 meters in altitude, suicide rates increase by 0.4 per 100,000.

Counties with higher-than-average suicide rates also tended to have a lower percent of African-American residents, a higher percent of people 65 years or older, a higher percent of smokers and lower scores for family and social support.

Linking altitude and suicide

Our findings suggest a need for further investigation into the extent by which altitude may serve as a triggering factor for suicide. This could have major implications in how medical professionals understand the causes of suicide.

We controlled for multiple socioeconomic, demographic and clinical factors, such as unemployment rate and the ratio of population to primary care physicians. This did not change our findings. In other words, this novel finding is not explained by county differences in socioeconomic and demographic factors.

Why might counties at higher altitudes – primarily observed in the western region of the country – be more likely to have higher suicide rates? One reasonable explanation could be the effects of hypoxia, or a deficiency in the amount of oxygen reaching the tissues. This can influence the body's metabolism of serotonin, one of the neurotransmitters related to aggressive behavior and suicide. Several studies suggest that chronic hypoxia increases mood disturbances, especially in patients with emotional instability.

However, without further clinical study, it is difficult to pin down exactly what biological mechanism is affected by .

Explore further: Suicide attempts on the rise in US, finds study

Related Stories

Suicide attempts on the rise in US, finds study

September 13, 2017
New data confirm that suicide attempts among U.S. adults are on the rise, with a disproportional effect on younger, socioeconomically disadvantaged adults with a history of mental disorders. The study, by researchers at Columbia ...

Older adults may need better follow-up after ER screenings for suicide

August 9, 2017
According to the World Health Organization, suicide rates for men over the age of 70 are higher than in any other group of people. In 2015, almost 8,000 older adults committed suicide in the U.S., and the proportion of suicides ...

Thin air, high altitudes cause depression in female rats

March 26, 2015
In a novel study, University of Utah (U of U) researchers have shown that hypobaric hypoxia (the reduced oxygen experienced at high altitude) can lead to depression.

Among active duty military, Army personnel most at risk for violent suicide

June 6, 2016
A study of rates and predictors of suicide among active duty enlisted service members found that Army personnel were most at risk for violent suicide. Firearms were determined to be the primary cause of suicide death across ...

Recommended for you

Young children use physics, not previous rewards, to learn about tools

February 23, 2018
Children as young as seven apply basic laws of physics to problem-solving, rather than learning from what has previously been rewarded, suggests new research from the University of Cambridge.

Study: Tinder loving cheaters—dating app facilitates infidelity

February 23, 2018
The popular dating app Tinder is all about helping people form new relationships. But for many college-aged people, it's also helping those in relationships cheat on their romantic partners.

Looking for the origins of schizophrenia

February 23, 2018
Schizophrenia may be related to neurodevelopmental changes, including brain's inability to generate an appropriate vascular system, according to new study resulted from a partnership between the D"Or Institute for Research ...

Color of judo uniform has no effect on winning

February 22, 2018
New research on competitive judo data finds a winning bias for the athlete who is first called, regardless of the colour of their uniform. This unique study, published in Frontiers in Psychology, puts to rest the debate on ...

Antidepressants are more effective than placebo at treating acute depression in adults, concludes study

February 22, 2018
Meta-analysis of 522 trials includes the largest amount of unpublished data to date, and finds that antidepressants are more effective than placebo for short-term treatment of acute depression in adults.

Infants are able to learn abstract rules visually

February 22, 2018
Three-month-old babies cannot sit up or roll over, yet they are already capable of learning patterns from simply looking at the world around them, according to a recent Northwestern University study published in PLOS One.

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

BubbaNicholson
3 / 5 (1) Nov 08, 2017
Check the phenomenon with other countries.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.