Stop for a moment, especially if you’re about to take a big bite of chocolate cake, and think about what happens to your kitchen drain pipes when you pour meat grease or chicken fat down the sink. Over time, this sludge builds up in the pipes, causing them to drain slower or blocking them completely. The same thing can happen to our blood vessels when they are exposed to high levels of cholesterol. LDL slowly builds up in artery walls, causing a thick plaque that can narrow arteries, restrict blood flow, and lead to blood clots. A blocked blood vessel in the brain can trigger a stroke. If the coronary arteries of the heart become blocked, a heart attack occurs. Heart attack is a major risk factor for heart failure, a condition in which damaged or weakened heart muscle is unable to pump enough blood to meet the body’s needs for blood and oxygen. But a new study shows that high levels of cholesterol may significantly raise the risk of heart failure, even for people who never have a heart attack.
Heart failure is a very common condition, affecting about 5 million Americans. Each year in the United States, it results in about 300,000 deaths and is responsible for more hospitalizations than all forms of cancer combined. The most common causes of heart failure are coronary artery disease (CAD), high blood pressure, and diabetes. Treating these underlying problems can prevent or improve heart failure. For instance, drugs called ACE inhibitors lower blood pressure and reduce strain on the heart and beta blockers slow the heart rate and lower blood pressure to decrease the heart’s workload. In trials, cholesterol-lowering drugs called statins were also shown to reduce the incidence of heart failure, but it has been unclear whether the reduction was due to abnormal lipids or a benefit of the reduction in heart attacks.
To investigate the relationship between lipid levels and heart failure, researchers at the National Heart, Lung and Blood Institute analyzed data on 6,860 participants in the Framingham Heart Study, none of whom had heart disease when they were enrolled. The group had an average age of 44 at the beginning of the study, and 54 percent were women. After an average 26 years of follow-up, 680 had developed heart failure. The incidence of heart failure was:
- 12.8 percent in those with low levels of high-density lipoprotein (HDL), the “good” cholesterol, but only 6.1 percent in those with desirable HDL levels.
- 13.8 percent in those with high levels of low-density lipoprotein (LDL), the “bad” cholesterol, compared to 7.9 percent in those with desirable levels of LDL.
After adjusting for age, sex, body mass index, blood pressure, diabetes, smoking and other factors, the risk of heart failure was 29 percent greater in those with high LDL cholesterol compared with those who had desirable lower levels, but 40 percent less in those with high levels of desirable HDL compared with those who had lower levels. The risk of heart attack was 13 percent higher in participants with high LDL cholesterol and 25 percent lower in those with high HDL cholesterol.
“This study goes a step further in implicating cholesterol levels in heart failure and suggests that cholesterol-altering therapy may have long-term benefits in preventing heart failure above and beyond its effects on preventing (heart attack),” said Dr. Daniel Levy, senior author of the study and director of the Framingham Heart Study. “For example, if lipids infiltrate the heart, like they do the liver, this might be one reason that people with diabetes are predisposed to heart failure.”
Levy said that because the study was not a randomized clinical trial, it should not be used to alter how physicians prescribe cholesterol-lowering drugs. He added, however, that it might be possible to reanalyze data from previous clinical trials of statins, eliminate people who had heart attacks and determine whether heart failure was lower in other people taking the drugs.
Over 100 million Americans have cholesterol levels that exceed the recommended total and 20 percent of Americans have levels that are considered high. Besides medications, the best ways to improve cholesterol levels include physical activity, smoking cessation, modest alcohol consumption, and eating a diet high in monounsaturated fats such as olive oil.
The study is published in the November 23 online edition of the journal Circulation.
by – Madeline Ellis/healthnews.com
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