Though the dementia rate has declined in the United States, the growing number of older Americans means more people will develop it. At the same time, gun sales have risen dramatically.

Perhaps not coincidentally, suicide rates have also climbed, up 28 percent from 1999 to 2016. More than 8,200 older adults committed suicide in 2016, according to the Centers for Disease Control and Prevention. Among men, those over age 65 are the likeliest to take their lives, and three-quarters of them use a gun.

“Suicide risk is elevated in people with dementia, but it’s more of a factor early in the illness,” said Dr. Yeates Conwell, a psychiatrist and director of the Office for Aging at the University of Rochester School of Medicine.

Later on, “people are less able to organize a suicide attempt and more apt to be under supervision.”

While older adults make many fewer suicide attempts than younger cohorts, they die more often, in part because they use such lethal methods. Yet health care providers who ask older patients about driving and wandering may not ask about guns.

“Safety planning for adults with dementia is something every clinician thinks about, but I don’t think firearms are often on the radar,” said Dr. Donovan Maust, a psychiatrist at the University of Michigan Medical School and co-author of a recent article on guns and dementia in the Annals of Internal Medicine.

They should be. At various stages of dementia, people may grow unable to distinguish loved ones from intruders. Their decision-making ability deteriorates. They can become paranoid, depressed, impulsive, agitated or aggressive.