Despite the sharp rise in obesity in the United States, cholesterol levels in older Americans have fallen markedly over the past 40 years, mainly because of the introduction of statin drugs in the late 1980s, a government study found.
Statins — which include such widely used medicines as Lipitor, Zocor and Pravachol — can dramatically reduce levels of LDL cholesterol, the bad kind that can clog arteries and lead to heart attacks. The drop in Americans’ overall cholesterol levels resulted from a decline in LDL.
Between 1960 and 2002, average total cholesterol levels for men and women ages 20 to 74 dropped from 222 milligrams per deciliter of blood to 203, mostly because of declines in people 50 and up. Among Americans ages 60 to 74, average levels fell from 232 to 204 in men (a 12 percent decline) and from 263 to 223 in women (down 15 percent). Below 200 is considered desirable for people at average risk for heart disease.
Also, in the study’s final decade, the percentage of adults with high cholesterol — a reading of at least 240 — fell from 20 percent to 17 percent, about eight years sooner than the government’s goal of reaching the 17 percent mark by 2010.
Use of statins increasing
At the same time, the portion of adults using cholesterol-lowering drugs, mostly statins, increased from 3.4 percent to 9.3 percent, with higher rates in the oldest Americans.
Senior author Clifford Johnson, a researcher with the Centers for Disease Control and Prevention, called the figures a glimmer of good news, although cholesterol levels were mostly unchanged in adults under 50.
Other government studies have shown that between 1988 and 2002, the percentage of overweight American adults climbed from 56 percent to 65 percent, while obesity rates increased from 23 percent to 30 percent. Obesity is often accompanied by high cholesterol levels, and both factors raise the risk of a heart attack or a stroke.
The study appears in Wednesday’s Journal of the American Medical Association. It is based on a comparison of data from periodic government health surveys.
Co-author Dr. James Cleeman, coordinator of the government’s National Cholesterol Education Program, said a slight reduction in Americans’ consumption of saturated fat probably contributed to the cholesterol declines.
Annual deaths from heart disease in the United States dropped from nearly 800,000 in the late 1980s to about 650,000 in 2002. Cleeman said falling cholesterol levels may have contributed to that decline. Still, cardiovascular disease remains the nation’s No. 1 killer.
“Statins are great but if you put statins in the water supply, cardiovascular disease would still be the leading cause of death in America,” said Dr. Steven Nissen, a Cleveland Clinic cardiologist who was not involved in the study.
Triglycerides on the rise
Cleeman also noted an ominous sign: The study found a slight increase in levels of triglycerides, another blood fat linked to heart disease. The researchers said the increase — if it is real and not a statistical fluke — probably reflects rising obesity rates.
Average levels of HDL cholesterol, the good kind that helps remove fats from blood, remained mostly stable during the study. Researchers increasingly believe that boosting HDL levels is a key to preventing cardiovascular disease, and pharmaceutical companies are racing to create drugs that achieve this.
Notable declines in LDL cholesterol levels were observed between 1976 and 2002, when average levels dropped from 138 to 123 in all adults. Again, the largest declines were in men over 60 and women over 50. Government guidelines set the upper limit at 130 for people at average risk for heart disease.
More recent declines were noted in a separate report this week from Quest Diagnostics, a leading provider of diagnostic testing. Between 2001 and the end of 2004, average LDL levels fell from 123.7 to 111.7 in U.S. adults 20 and older under a doctor’s care. The largest decline were in adults 70 and older.
The report is based on nearly 80 million test results reported by Quest labs nationwide.