MONDAY, Dec. 12, 2005 (HealthDay News) -- Younger adults don't seem to be getting the message about the importance of low blood cholesterol, according to the latest report from a decades-long study.
Total cholesterol levels have decreased in middle-aged to older adults over the past twenty years, but they have risen in the 25-to-34 age group, said a new report on the Minnesota Heart Survey.
The survey has followed more than 2,500 adults in the Minneapolis-St. Paul area for two decades. The first report, covering 1980 to 1982, found cholesterol readings of 212 milligrams per deciliter of blood for men and 208 milligrams for women. By 2000-2002, the levels were 199 for men and 197 for women.
"However, the decline is not uniform across age groups," said study author Donna K. Arnett, chairwoman of epidemiology at the University of Alabama at Birmingham. "Young men and women ages 25 to 34 have not shown any significant change in total cholesterol across the study, and in the past decade they have posted at least one significant increase on some part of the survey."
Cholesterol readings for women in that age group increased by 1 percent between 1990-1992 and 1995-1997, and again between 1995-1997 and 2000-2002 -- a seemingly small rise that nevertheless was statistically significant, the researchers said.
The story for men of the same age was more complicated, with a 4 percent increase between 1990-1992 and 1995-1997, followed by a 3 percent drop between 1995-1997 and 2000- 2002. Over the total period, there was a slight rise in cholesterol levels for men, but one that did not reach statistical significance.
The study findings appear in the Dec. 13 issue of Circulation.
One reason for the overall decrease is that more older people are taking cholesterol-lowering drugs, the researchers said. Their use doubled in the over-35 group, but it is "almost nonexistent for the 25- to 34-year-olds, who do not perceive the risk of elevated cholesterol concentrations," Arnett said.
And the overall picture was not altogether cheerful. More than half of all adults have readings over 200, classified as borderline "high risk" by the National Cholesterol Education Program. And more than half of those in the survey with those high cholesterol levels were unaware of their condition, the researchers said.
Meanwhile, a report in the Dec. 13 issue of Hypertension adds one more motivation for keeping cholesterol levels low. Data from the Physicians' Health Study showed that men with high cholesterol levels are much more likely to develop high blood pressure, a significant risk factor for heart disease and stroke.
Of the more than 3,000 men in the study, those in the highest 20 percent of cholesterol readings were 39 percent more likely to develop high blood pressure than those in the lowest 20 percent, the report said.
"The idea is that cholesterol reflects the underlying state of the arteries," said study author Howard D. Sesso, an associate epidemiologist at Brigham and Women's Hospital in Boston. High cholesterol levels reduce the elasticity of the arteries, making them less able to expand in response to blood flow, he said.
And the finding applies to women as well as men, Sesso said.
"About a month ago we reported a similar study in women which also found the same conclusion," he said. "When you have elevated levels of cholesterol, that is a general indication of the early manifestation of cardiovascular disease."
The American Heart Association has more on blood cholesterol levels.