(CNN) - The suicide rate rose 41% in the United States from 1999 to 2016, and the people at the highest risk have a few factors in common, according to a study published in the journal JAMA Network Open on Friday.
Men had higher suicide rates. Areas with the highest risk were in Western states, and in rural areas. Or, in a city, if there was a gun shop in the neighborhood.
"With the gun shop, this is a new variable that hasn't really been looked at, so that definitely needs more research, but we think it is about accessibility," said co-author Danielle Steelesmith, a researcher with the Ohio State University Wexner Medical Center.
The majority of the nearly 40,000 gun deaths in the United States in 2017 were due to suicide, according to US Centers for Disease Control and Prevention data.
People who were uninsured were also more at risk for suicide.
"We found several health-related variables, but we found being uninsured did increase suicide rates," said Steelesmith. "We think it's related to accessibility. People who don't have insurance likely can't afford to seek out the kind of help they need or they may not even know where to look for help, especially in rural areas."
The study authors looked at 453,577 adult suicides in 1996 to 2016, ranging from 25 to 64 years old. Researchers determined the suicide rate jumped from a median of 15 per 100,000 county residents in 1999 to 2001 to 21.2 per 100,000 in 2014 to 2016.
In 2014 through 2016, suicide rates were 17.6 per 100,000 in large cities compared with 22 per 100,000 in rural areas.
Counties with the highest suicide rates were in Utah, Colorado, New Mexico and Wyoming, in Appalachian states including Kentucky, West Virginia and Virginia, and in Missouri and Arkansas.
Earlier research has found that suicide is a leading cause of death in the United States and the rates have increased in nearly every state, according to the CDC. In 2017, 23,854 people died from suicide by guns, the highest number in 18 years. That's a difference of more than 7,000 deaths compared with 16,599 suicide deaths by guns in 1999.
Drug addiction, financial trouble, housing problems, loneliness, job and legal stress also put people at risk, as does a family history of suicide, family violence, and being exposed to someone who had suicidal behavior, including a celebrity suicide.
"We did find that social connections are protective," said Steelesmith. "Connecting with other people matters and there are opportunities to do that and it doesn't cost anything. That could certainly be something someone could do in any region to help. Find ways to connect with others."
How to get help: In the US, call the National Suicide Prevention Lifeline at 1-800-273-8255. The International Association for Suicide Prevention and Befrienders Worldwide also can provide contact information for crisis centers around the world.
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