TUESDAY, Oct. 11, 2005 (HealthDay News) -- Cholesterol levels are dropping in older Americans, most likely the result of increased use of lipid-lowering drugs called statins.
But experts warn that these drugs are no replacement for lifestyle changes to reduce cardiovascular risk, especially given that triglyceride levels -- fats in the blood -- went up during the same time period.
"Statins are sometimes perceived by their recipients as a credit card to eat indiscriminately," said Dr. Howard Weintraub, co-clinical director of the Lipid Treatment & Research Center at New York University Medical Center. "Low-density lipoprotein cholesterol is not the only risk factor for heart disease. We all know that triglycerides increase atherosclerotic risk. This is not good news. This is a Trojan horse."
Weintraub was not involved with the study, which appears in the Oct. 12 issue of the Journal of the American Medical Association.
High total and low-density lipoprotein (LDL, or "bad") cholesterol levels are established risk factors for atherosclerosis ('hardening of the arteries') and other cardiovascular problems.
Clinical trials have suggested that a 1 percent decrease in LDL cholesterol reduces the relative risk for coronary heart disease by an equivalent 1 percent.
Previous data had shown declines in total cholesterol levels in U.S. adults between 1960-62 and 1988-94 and in LDL cholesterol levels between 1976-80 and 1988-94.
This study brings trend information up to date by examining data from five separate national surveys of the U.S. population during 1960-62, 1971-74, 1976-80, 1988-94 and 1999-2002.
The total cholesterol levels of adults 20 years or older decreased from 206 mg/dL (milligrams per deciliter of blood) in 1988-94 to 203 mg/dL in 1999-2002, while the average LDL cholesterol level decreased from 129 mg/dL to 123 mg/dL during the same time period.
According to the American Heart Association, total cholesterol levels should be less than 200 mg/dL. Those with cholesterol levels of 240 mg/dL and over are considered high risk. Optimally, LDL levels should be less than 100 mg/dL.
The percentage of adults with total cholesterol levels of at least 240 mg/dL decreased from 20 percent in 1988-94 to 17 percent in 1999-2002, achieving one of the Healthy People 2010 objectives set by the U.S. government.
The declines in total and LDL levels were primarily confined to men 60 years or older and to women 50 years or older, not younger adults. This coincides with increased use of statins in this segment of the population. Between 1995-96 and 2001-02, there was an increase in the number of physician office visits and hospital visits of men and women over 45 in which statins were prescribed, the study found.
Average high-density lipoprotein (HDL, or "good") cholesterol levels did not change while triglyceride levels in adults 20 years and older increased from 118 mg/dL in 1988-94 to 123 mg/dL in 1999-2002. This last number was not statistically significant although it may be significant nonetheless, health experts said.
"Triglycerides are reflective of metabolic problems that are up in everybody," Weintraub said.
And all of this is occurring in a climate when obesity and overweight are expanding exponentially. According to the U.S. Centers for Disease Control and Prevention, between 1988-94 and 1999-2002 the proportion of overweight and obese adults in America increased from 55.9 percent to 65.1 percent. The prevalence of obesity alone increased from 22.9 to 30.4 percent, trends which likely contributed to triglyceride increases.
"People are going to read this and say, 'We're not in trouble,' and yet obesity is increasing significantly," Weintraub said. Obesity contributes to diabetes, which, in turn, contributes heavily to the burden of heart disease in this country.
"I'm happy to see that cholesterol is coming down," Weintraub added. "Statin medicines work very well and lower cholesterol levels and may minimize some of the impact of poor diet. But as people have lowered their fat intake, they've gotten heavier, which means they're eating carbohydrates and their triglycerides are going up."
The National Cholesterol Education Program has more on controlling cholesterol levels and maintaining a healthy lifestyle.