Boston, MA -- An analysis of 69 assisted suicides supervised by Jack Kevorkian has concluded that 75 percent of his patients were not terminally ill when he helped them to die, and that autopsies could not confirm any physical disease in five of the cases.

The study's findings were reported in a letter to the New England Journal of Medicine and were made available on Wednesday.

The journal, which will be published on Thursday, said a team led by Lori A. Roscoe of the University of South Florida at Tampa looked at the characteristics of people who died with Kevorkian's assistance in Oakland County, Michigan between 1990 and 1998.

Kevorkian, who helped more than 100 people commit suicide, is serving a prison sentence of 10 to 25 years in Michigan. He was convicted of second degree murder in April 1999 in a trial that followed an appearance on national television in which he administered a lethal injection to Thomas Youk, a 52-year-old man suffering from Lou Gehrig's disease, and dared the criminal justice system to stop him.

The study's findings seemed to suggest divorcees or people who had never married were more likely to turn to assisted suicide in the absence of safeguards.

Roscoe and her colleagues said "persons who were divorced or had never married were overrepresented among those who died with Kevorkian's help, suggesting the need for a better understanding of the familial and psychosocial context of decision making at the end of life."

They said only 17 of the 69 patients were found after autopsy to be terminally ill and likely to live less than six months.

The wish of the other 52 people to get help from Kevorkian might be explained by the fact that "72 percent of the patients had had a recent decline in health status that may have precipitated the desire to die," the researchers said.

Of the 69 patients, 71 percent were women, which "is noteworthy because suicide rates are usually lower among women than among men," they concluded.

The Roscoe team only looked at the Michigan cases because the procedures of medical examiners in other states may have varied.

Kevorkian's attorney, Mayer Morganroth, dismissed the study. "All they're doing is repeating allegations made by the pro-life people," he told Reuters. "They're not really of any real substance, and they're not really accurate or true."

He also attacked the authors, pointing out that Roscoe and another person involved were not medical doctors, and that a third person involved, Oakland County medical examiner L.J. Dragovic, had testified numerous times against Kevorkian and the two men were "bitter enemies."