Cholesterol levels down overall

Total cholesterol levels have decreased in middle-aged to older adults but are rising among younger adults, according to a survey reported in Circulation: Journal of the American Heart Association.

The Minnesota Heart Survey (MHS), an ongoing population-based surveillance of trends in heart disease among 2,500 to 5,000 adults in the Minneapolis/St. Paul area, mirrors national trends.   It has assessed 20-year trends in the incidence of high cholesterol, cholesterol-lowering drug use, and cholesterol awareness, treatment and control from l980-2002.Overall, the age-adjusted average total cholesterol levels in the 1980–82 survey were:

• 212 milligrams per deciliter (mg/dL) or 5.49 millimoles per liter (mmol/L) for men and
• 208 mg/dL (5.38 mmol/L) for women.

In 2000–02, the levels dropped to

• 199 mg/dL (5.16 mmol/L) for men and
• 197 mg/dL (5.09 mmol/L) for women.

“These findings extend the trend of generally declining total cholesterol concentrations that have been observed nationally since 1960; however, the decline is not uniform across age groups,” said Donna K. Arnett, Ph.D., professor and chair in the department of epidemiology at the University of Alabama at Birmingham and lead author of the study.“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,” she said.The total cholesterol of women 25 to 34 increased by about 1 percent between both the 1990-92 and 1995-97 surveys and the 1995-97 and 2000-02 surveys.  Although these increases may seem small, both jumps were statistically significant, researchers said. In the same age group in men, the picture is more complicated, and overall trends in the recent data are not as clear.  Total cholesterol in these men increased by about 4 percent between the 1990-92 and 1995-97 surveys but then decreased by about 3 percent between the 1995-97 and 2000-02 surveys.   Both of these changes were statistically significant.   Although this means young men experienced an overall rise during the past 10 years, this decade-long trend did not reach statistical significance.In men from 1980–82 to 1995–97, total cholesterol was highest in either the 45- to 54- or 55- to 64-year-olds.  In 2000–02, the 35- to 44-year-olds showed the highest cholesterol levels.Researchers also found that use of cholesterol-lowering drugs among people over age 35 roughly doubled between 1990-92 and 2000-02.   However, medication use is “almost non-existent for the 25- to 34-year-olds, who do not perceive the risk of elevated cholesterol concentrations,” Arnett said.“The older age groups use more lipid-lowering drugs.  This may be partially responsible for the continued reduction of their total cholesterol.”Although U.S. cholesterol concentrations have continued to drop, about 50 percent of adults have total cholesterol concentrations of more than 200 mg/dL (5.18 mmol/L).  According to the National Cholesterol Education Program (NCEP), this is “borderline-high risk” for heart disease.Despite increased awareness, treatment and control of high cholesterol, the survey found that more than half of those at or above borderline-high risk remain unaware of their condition.The percentage of adults who know they have high cholesterol but are not treating it with drugs has declined throughout the study, but remains high: 58.5 percent for men and 73.7 percent for women.Arnett called for improvements in behavioral, dietary and medication control of cholesterol in young adults.“We want to get the message out to young adults to decrease their cholesterol and fat intake,” she said.  “We want to encourage young adults to pay attention to the cholesterol and fat in their diets and to be screened for high cholesterol.  They should discuss with their doctors whether taking cholesterol-lowering medications might be appropriate for them.”The American Heart Association endorses the NCEP guidelines for detecting high cholesterol, which recommend that everyone age 20 and older have a fasting “lipoprotein profile” every five years.    This test gives information about total cholesterol, low-density lipoprotein (“bad” cholesterol), high-density lipoprotein (“good” cholesterol) and triglycerides (blood fats).High cholesterol is a major contributor to coronary heart disease.  CHD is the single major cause of death in the United States, leading to more than one in every five deaths.Co-authors of the study are David R. Jacobs Jr., Ph.D.; Russell V. Luepker, M.D.; Christopher Armstrong, Ph.D.; and Steven A. Claas, M.S.

The study was funded by the National Heart, Lung, and Blood Institute and the National Institutes of Health.