Legalized euthanasia and physician-assisted suicide are mainly used by patients with cancer, but remain rare, according to a new analysis of such programs.

In the last year alone, California has legalized physician-assisted suicide, Canada legalized both physician-assisted suicide and euthanasia, and Colombia performed its first legal euthanasia, said John Urwin, a study author from the Perelman School of Medicine at the University of Pennsylvania in Philadelphia. "In order to inform current debates, it's imperative to understand current laws and practices."

Definitions of euthanasia and physician-assisted suicide vary between countries, Urwin and his colleagues write in JAMA.

Generally, they explain, euthanasia is when a doctor takes action to end a patient's life. When patients take physician-prescribed pills to end their lives, it's known as physician-assisted suicide.

The researchers assessed the legal status of euthanasia and physician-assisted suicide by reviewing polling data and published surveys of the public and physicians, official state and country databases, interview studies with physicians and death certificate studies for the period 1947 to 2016.

They found no evidence for widespread abuse of these practices, according to their report.

In addition to Canada and Colombia, the practices are at least partially legal in the Netherlands, Belgium and Luxembourg. Physician-assisted suicide is also legal in the U.S. states of Oregon, Washington, Montana and Vermont.

Overall, support for physician-assisted suicide and euthanasia varies around the world.

Support for physician-assisted suicide in the U.S. increased from 37 percent in 1947 to 53 percent in the early 1970s and leveled off around 1990, with two-thirds of people in the U.S. supporting the practice.

In Western Europe, they write, support for physician-assisted suicide and euthanasia is strong and increasing. Meanwhile, support is decreasing in Central and Eastern Europe.

Researchers need better data on practices in countries with and without legalized physician-assisted suicide and euthanasia, Urwin told Reuters Health by email.

His team found that in countries where the practices are legal, 0.3 to 4.6 percent of deaths are attributed to physician-assisted suicide and euthanasia.

Over two-thirds of cases involved patients with cancer, they write.

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Urwin said people mainly request physician-assisted suicide or euthanasia due to "loss of autonomy and inability to enjoy life rather than pain."

Most people requesting those types of deaths are older, white, and well-educated, he added.

Data from California will be important, Urwin said.

"As the largest and most diverse U.S. state to have legalized (physician-assisted suicide), it will be interesting to see if the characteristics of those seeking (physician-assisted suicide) are similar to those of the other states that have done so," he said. "Depending on how (physician-assisted suicide) is received in California, other states may be more or less likely to pass similar legislation."