Diabetes and Heart Disease are
Closely Linked

By: Judy Foreman
10/05/2004

More than 30 years ago, when Dr. David Heber was an intern at Beth Israel Deaconess Medical Center, he asked the senior doctors the same question over and over.

"How come all my patients have high blood pressure, high cholesterol and diabetes? Are these things linked?" His mentors would shrug and say, "Dave, common things occur commonly. Go back to work," he said.

Today, doctors know Heber’s intuition was right. Type 2 diabetes and heart disease are physiologically linked. What’s more, according to new government figures, a whopping 64 million Americans now have what's called Metabolic Syndrome [cq caps], also known as  insulin resistance, which doubles the risk of heart disease and raises diabetes risk by 30 percent.

"It’s a chain from obesity to diabetes to heart disease," said Heber, now director of UCLA’s Center for Human Nutrition. "In the next 10 years, 80 percent of all heart disease will be due to Type 2 diabetes."

Granted, you may never have heard of Metabolic Syndrome. But you probably have it if you have any three of the following five factors:

§        Abdominal obesity, as gauged by a waist circumference of 40 inches or more for men, 35 for women.

§        Elevated triglycerides (150 milligrams per deciliter or more)

§        Low HDL or "good" cholesterol (less than 40 mg/dl in men, 50 in women)

§        High blood pressure (130 millimeters of mercury or higher, over 85 mm or more)

§        Moderately elevated fasting blood sugar (110 mg/dl to 125 mg/dl).

The pace at which Americans, especially women, are falling prey to this nasty cluster of symptoms is increasing shockingly fast.  In this month’s [October]  issue of Diabetes Care, researchers from the federal Centers for Disease Control and Prevention said that between one study done from  1988 through 1994 and another done in 1999-2000, there was "a significant increase" in the prevalence of the metabolic syndrome in adults aged 20 and older.

But while the rise in metabolic syndrome among men was relatively small, 2.2 percent, among women it was  23.5 percent, driven in large part by rising obesity. In recent years, tens of millions of female Baby Boomers have been going through menopause, which typically leads to an upper body weight gain of 12 to 20 pounds. 

While heart disease does not cause diabetes, diabetes -- or  insulin resistance -- can lead to heart disease. Having   diabetes,  "is the equivalent of already having had a heart attack in terms of the risk of having a new heart attack," said Dr. Edward S. Horton, vice president and director of clinical research at the Joslin Diabetes Center.

Metabolic Syndrome "is not a disease per se,"   said Dr. Paul Ridker, director of the center for cardiovascular disease prevention at Brigham and Women’s Hospital, .  but "it is  an important warning sign that something has to be done." The term hammers home the point that heart disease and diabetes, "while seemingly different, share a common soil."

But metabolic syndrome is still treated piecemeal, as a bunch of symptoms, rather than one, linked problem.   Doctors use separate drugs to control blood pressure, cholesterol and triglycerides. Drugs approved to treat diabetes are not yet approved for metabolic syndrome -- though trials to gauge their usefulness for this are underway.

The far better approach to treating the overall problem, Ridker and others said, is the hard, low-tech way: by losing weight through diet and exercise.

The good news is "you don’t have to lose a ton of weight to partially reverse Metabolic Syndrome," said Dr. Richard Nesto, Chairman of the Department of Cardiovascular Medicine at the Lahey Clinic and one of the country’s foremost experts on the overlap between heart disease and diabetes.

"You only have to lose 12 to 16 pounds to see marked improvement in cholesterol, blood pressure and CRP,"  or C-reactive protein, a marker of inflammation that some doctors believe should be part of the definition of Metabolic Syndrome. The reason losing weight is so crucial, as opposed to fighting symptoms one by one, is that stored fat in the abdomen -- not the subcutaneous blubber you can grab with your hands, but the deep fat that wraps itself around internal organs -- pumps out chemicals that drive both Type 2 diabetes and heart disease. So-called visceral fat is a biologically active organ. "It’s a little factory in the belly that makes bad hormones," as Nesto put it.

Here’s what scientists think is going on. Stored fat makes inflammatory chemicals called cytokines, which trigger inflammation all over the body, including in blood vessel walls. Cytokines also raise CRP, which in turn raises the risk of heart disease, even in people with normal cholesterol. Cytokines also increase the tendency for blood to clot, triggering potentially fatal heart attacks. They also raise blood pressure and worsen cholesterol profiles. And they cause  narrowing of arteries, including those that feed the heart and other vital organs.

Just as important, cytokines from fat also mess up the delicate system by which insulin, the hormone that escorts sugar into cells, sends its chemical signals inside cells. Faulty insulin signaling in turn triggers insulin resistance, which  forces the pancreas (which makes insulin) to work harder and harder until it finally gives out, creating full-blown diabetes.

Meanwhile, fat cells also release free fatty acids, which flock to the liver, where they are linked together into little bundles (triglycerides) and pumped back into the blood. In high enough amounts, these triglycerides disrupt cholesterol balance, making levels of "good" (HDL) cholesterol fall.

"Fatty acids are also toxic in themselves," said Dr. George L. Blackburn, associate director of nutrition in the Division of Nutrition at Harvard Medical School.

All in all, not a pretty picture. You can take statin drugs like Lipitor or Zocor to lower "bad" or LDL cholesterol and reduce C-reactive protein levels. You can take diuretics, ACE-inhibitors or other drugs, to lower blood pressure.  You can take Lopid or Tricor to lower triglycerides and Niaspan to boost "good" cholesterol.

You can also take some drugs that are approved for diabetes but not yet for insulin resistance, among them Glucophage, Avandia and Actos.

But the best solution, is to take an ordinary tape measure and measure your waistline. If your girth is too great, get serious about losing weight.

Judy Foreman’s column appears every other week. Past columns are available on www.myhealthsense.com.

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