In the U.S., a decades-long trend toward less heart disease has ended -- and may now be going the other way.
The finding comes from an unexpected source -- autopsies of the heart arteries of 425 people aged 16 to 64 who died in accidents, homicides, or from other "non-natural causes" from 1981 to 2004.
Year after year, Mayo Clinic researcher Cynthia L. Leibson, PhD, and colleagues found less heart disease in these non-elderly adults -- until 1995. At that point, the downward trend ended.
"The prevalence of coronary artery disease is not continuing to decline," Leibson tells WebMD.
After 2000, the study findings suggest, heart disease may actually have begun to increase, although this disturbing finding did not reach statistical significance.
"These trends are not unexpected in light of trends in obesity and diabetes . But we have no evidence here that one caused the other," Leibson says.
Other studies have indeed linked childhood obesity to adult heart disease . This makes the relatively young people in the Leibson study "canaries in the coal mine" of heart disease, says S. Jay Olshansky, PhD, in an editorial accompanying the Leibson team's report in the Feb. 11 issue of Archives of Internal Medicine.
"In my view, this is an absolutely shocking study. It is an indication of where things are headed," Olshansky tells WebMD. "It is a sign we may be on the verge of an increase in cardiovascular disease and in the death rate from cardiovascular disease."
In an often-cited 2005 article in The New England Journal of Medicine, Olshansky and colleagues have warned that the childhood obesity epidemic threatens to shorten the average American life span .
This would happen in three phases. The first, an increase in obesity, already has happened. The second phase would be an increase in coronary artery diseases as these children age.
"The Leibson study is only the latest to suggest that phase two is already here," Olshansky says. "Phase three would be complications, some of them lethal, as these people reach their later 20s, 30s, and 40s. They will have higher mortality risks as they pass through the same age windows as previous generations. This is further corroboration of our conclusion back in 2005."
It's not too late, say Leibson and Olshansky agree.
"We need to begin monitoring these young generations sooner to identify problems and treat them earlier," Olshansky says.
"Medical science is moving forward. Medications are being developed and cures are found every day," Leibson says. "So just because we see the prevalence and grade of coronary artery disease has stopped declining -- and we can say that pretty comfortably -- this doesn't mean we won't continue to make improvements in survival following heart disease."
Even so, Olshansky finds the study findings scary.
"They show that when you look inside the bodies of younger people today, you see something unexpected. You see evidence they are facing higher risks for heart diseases than previous generations at the same age. That is what is frightening," he says.
By Daniel DeNoon
Reviewed by Louise Chang
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