By Julie Steenhuysen
CHICAGO, Feb 11 (Reuters) - Autopsies of adults who died young of unnatural causes show many already had clogged arteries, U.S. and Canadian researchers said on Monday in a study that suggests heart disease may be on the upswing.
The researchers said their findings suggest a four-decade-long trend of declines in heart disease may be about to come to a screeching halt.
They studied autopsy reports from younger people in one Minnesota county who died from accidents, suicide and murder and found most had clogged arteries and more than 8 percent had significant disease.
"What they observed was a bit shocking," said S. Jay Olshansky of the University of Illinois at Chicago, who wrote an editorial on the research, published in the Archives of Internal Medicine.
"It is the most definitive evidence I've seen suggesting that today's younger and middle-aged generations may be heading for an increase in their risks of heart disease," he said.
The researchers from the Mayo Clinic in Minnesota and the University of British Columbia in Vancouver looked at autopsy data from residents of Olmsted County, Minnesota, who died between 1981 and 2004 from unnatural causes.
During that time, 8.2 percent of 425 people aged 16 to 64 had high-grade disease and 83 percent had the beginnings of coronary artery disease.
Mayo's Cynthia Leibson and colleagues found declines in the grade of coronary artery disease ended after 1995 and began to climb after 2000.
"Declines in coronary artery disease appear to have ended and there is some suggestion that they might be increasing," Leibson said in a telephone interview.
She said it is not yet clear to what extent obesity and diabetes contributed to this, but the researchers plan to study this in the same group of patients.
Olshansky, in a telephone interview, said rates of heart disease in the United States climbed steadily in the 20th century until the 1960s, and then began falling, helped by changes in lifestyle and declines in smoking. But then, a confluence of changes occurred.
"It was more or less a perfect storm," he said, citing the introduction of computers and a more sedentary lifestyle, the growth of fast-food chains and larger portion sizes, reduced physical education in schools and increased consumption of high-fructose corn syrup.
"It led to this explosion of obesity," Olshansky said.
A second study in the same journal confirms the trends.
Dr. Philip Mellen of the Hattiesburg Clinic in Mississippi analyzed national diet and nutrition data from a large federal study to see if patients with high blood pressure were adhering to a diet known to help control high blood pressure, a known cause of heart attacks and strokes.
They looked at data collected from 1988-1994, a period before a study in 1997 showed a diet high in fruits, vegetables and low-fat dairy products could significantly lower blood pressure. They compared this to data from 1999 to 2004.
What they found was people with hypertension were eating worse, not better. "The dietary quality has deteriorated over the last 15 years," Mellen said in a telephone interview.
"In our study, the youngest age group was the age group with the worse disease," he said. "This age group will have major problems as they continue to age." (Editing by Maggie Fox and Todd Eastham)