And, risks of heart attack and stroke increase when 'good' cholesterol levels go down
Oct. 7, 2011 - Increasing levels of high-density lipoproteins, better known as HDL or "good" cholesterol, reduced the
risk for heart attack and stroke among patients with diabetes. That's according to a new study appearing online today in The American
Journal of Cardiology.
The observational study, one of the largest of its kind, examined the medical records of more than 30,000 patients with
diabetes and also found that patients whose HDL levels decreased had more heart attacks and strokes.
Researchers studied patients with diabetes because they are more prone to heart disease with a lifetime risk as high as
87 percent, according to a paper from the landmark Framingham heart study published 2008.
While there is considerable evidence that reducing the amount of low-density lipoprotein, also known as LDL or "bad"
cholesterol, can reduce the risk of heart disease, the relationship between HDL cholesterol and heart disease is less clear.
"Our study adds to the growing body of evidence that raising HDL levels may be an important strategy for reducing heart
attack risk," said study lead author Gregory Nichols, PhD, senior investigator with the Kaiser Permanente Center for Health Research in
"This is promising news for patients with diabetes, who already have an increased risk for heart problems. Raising their
good cholesterol may be one more way for these patients to reduce their risk," said Suma Vupputuri, PhD, co-author and investigator with the
Kaiser Permanente Center for Health Research in Atlanta.
Senior citizens - Heart disease, stroke and diabetes
● In 2004, heart disease was noted on 68% of diabetes-related death certificates among
people aged 65 years or older.
● In 2004, stroke was noted on 16% of diabetes-related death certificates among people
aged 65 years or older.
● Adults with diabetes have heart disease death rates about 2 to 4 times higher than
adults without diabetes.
● The risk for stroke is 2 to 4 times higher among people with diabetes.
The study included 30,067 patients who entered Kaiser Permanente diabetes registries in Oregon, Washington and Georgia
between 2001 and 2006.
These patients had at least two HDL cholesterol measurements between 6 and 24 months apart.
Most patients (61 percent) had no significant change in HDL levels; in 22 percent of patients, HDL levels increased by at
least 6.5 mg/dl (milligrams per deciliter of blood); in 17 percent of patients, HDL levels decreased by at least that same amount.
After obtaining the cholesterol measurement, researchers followed the patients for up to 8 years to see if they were
hospitalized for a heart attack or stroke.
Patients whose HDL levels increased had 8 percent fewer heart attacks and strokes than patients
whose HDL levels remained the same, while patients whose HDL levels decreased had 11 percent more heart attacks and strokes.
This study was observational so there was no intervention to change HDL levels, and although many patients were on
statins to reduce their "bad" cholesterol, very few were on medications to improve HDL.
Past Studies Inconclusive
Past studies on this topic have reached contradictory conclusions. A study published in 2009 in the Archives of
Internal Medicine found that for every 5 mg/dl improvement in HDL cholesterol level patients saw a 21 percent decrease in heart attack
risk. But a systematic review of more than 100 clinical trials published in the British Medical Journal in 2009 found that increasing
HDL cholesterol did not reduce the risk of heart disease or death.
Earlier this year the National Institutes of Health stopped a clinical trial using large doses of the B Vitamin niacin to
boost HDL levels because the patients, who were already taking statins to reduce their "bad" cholesterol, saw no added reduction in heart
attacks when they added niacin. Niacin is one of very few medications to increase HDL, but it can also have side effects such as flushing,
vomiting, dizziness and itching.
People can raise their HDL levels without medication by keeping their weight down, changing their diet, avoiding tobacco
smoke, and increasing exercise. Medical experts believe that HDL or "good" cholesterol carries the "bad" cholesterol away from the arteries
and back to the liver where it is processed and passed from the body.
According to the American Diabetes Association, a good target for women should be at least 50 mg/dl of HDL and for men at
least 40 mg/dl. Levels of 60 mg/dl or higher are thought to protect against heart disease.
The study was funded by Takeda Pharmaceuticals America, which makes a diabetes medication called Actos (pioglitazone)
that other studies have shown modestly raises HDL. Authors include Gregory A. Nichols, PhD, and A. Gabriela Rosales, MS, from the Kaiser
Permanente Center for Health Research in Portland, Ore., and Suma Vupputuri, PhD, at the Kaiser Permanente Center for Health Research in
About the Kaiser Permanente Center for Health Research
The Kaiser Permanente Center for Health Research, founded in 1964, is a nonprofit research institution dedicated to
advancing knowledge to improve health. It has research sites in Portland, Honolulu, and Atlanta. (http://www.kpchr.org)
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