Body Fat Location Helps Predict Heart Risk

Study Revisits Body Shape Risk Factor

 < April 21, 2004 > -- The amount of body fat you carry around does not predict heart disease as well as its location does, according to a study reported at the Experimental Biology 2004 meeting in Washington D.C.

The findings should call into question the practice of recommending bariatric surgery solely on obesity rather than other heart disease risk factors, says Dr. Edward Harry Livingston, chairman of gastrointestinal and endocrine surgery at UT Southwestern Medical Center.

The finding applies especially to women, says Dr. Livingston, who performs the surgery. There are several types of bariatric surgery to treat severe obesity, the most common of which involves making the stomach smaller.

In his analysis, he found death from heart disease did not increase in a totally linear fashion the fatter people became.

And he found distribution of body fat, rather than overall weight, is a better predictor of heart disease risk, with fat on the abdomen more unhealthy than that on the thighs and hips.

"One of the reasons we do these operations is there is a concern for early mortality attributed to obesity," Dr. Livingston explains. Traditional thinking has it that the heavier a person is, the more heart disease risk factors he or she has.

Body Mass Index and Body Shape Reviewed

But Dr. Livingston had noticed among his patients that the degree of obesity did not always correlate with the amount of heart disease.

To begin his research, Dr. Livingston looked at two large national databases - the National Health Interview Surveys, from 1986 to 1994, as well as the National Death Index. He classified patients by body mass index (BMI) and looked at the prevalence of other heart disease risk factors such as blood pressure and cholesterol.

Death rates from heart disease increased for women when they passed a body mass index of 25 (about 160 pounds for a woman 5 feet 6 inches tall) and kept increasing until they reached a BMI of 30 (about 185 pounds for a woman of the same height) and then leveled off.

People are considered obese when their BMI reaches 30, and are overweight when their BMI is between 25 and 30.

If obesity alone was considered, a woman of that height was found no more likely to die of heart disease at a BMI of 50 (about 310 pounds) than at a BMI of 35 (215 pounds).

For men, the death rate from heart disease continued to increase as BMI climbed, with a steep increase at a BMI of 40 (279 pounds for a man 5 feet 10 inches tall). As the BMI increased in men, at least up to 50, the highest they evaluated, so did heart disease death risk, Dr. Livingston says.

Body Fat Distribution Revisited

Fat distribution was key to heart disease death risk, he also found. There was a negative correlation with the buttock or thigh fat and a positive correlation with waist diameter.

It is the apple-pear story that has been told before: those who collect fat around their middles and are apple-shaped are less heart-healthy than the pears, who collect fat around the buttocks and thighs.

Some who store fat in their lower bodies do not experience an increase in cholesterol, as do some who store it around their middle and become very obese with a rise in heart disease risk.

"What this means," says Dr. Livingston, "is that some people have the potential for becoming very obese by collecting fat in their lower body - but that does not necessarily correlate to cardiovascular disease risk factors."

Currently, Dr. Livingston says, the criteria for bariatric surgery is based on size alone, with those at a BMI of 40 and above considered candidates.

"This [study] adds another piece to the puzzle about cardiovascular disease risk factors," he says.

The findings do not indicate that being obese is without risk, Dr. Livingston explains. But they do suggest that not everyone who is obese is always at increased risk of dying from heart disease.

But a cardiologist familiar with the study would like to see more evidence to further support Dr. Livingston's findings.

"It's an interesting observation, but there is not enough information to convince me," said Zi-Jian Xu, a cardiologist at Santa Monica/UCLA Medical Center in California.

"When obesity increases, your risk of heart disease increases," he said. "We have no reason to think risk will level off."

Always consult your physician for more information.

Online Resources

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American Academy of Family Physicians

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Centers for Disease Control and Prevention (CDC)

HealthierUS.Gov

National Heart, Lung, and Blood Institute

National Institute of Diabetes & Digestive & Kidney Diseases

National Institutes of Health (NIH)

National Library of Medicine

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NIH Recommendations for a Healthy Lifestyle

According to the National Institutes of Health (NIH), the basis of a healthy diet is eating a wide variety of foods. Every day, a person should try to eat:

• six to 11 servings of bread, cereal, rice, or pasta. One serving equals one slice of bread, about 1 cup of ready-to-eat cereal, or 1/2 cup cooked cereal, rice, or pasta.

• three to five servings of vegetables. One serving equals 1 cup of raw leafy vegetables, or 1/2 cup of other vegetables, cooked or raw.

• two to four servings of fruit. One serving equals one medium apple, banana, or orange; 1/2 cup of chopped, cooked, or canned fruit; or 3/4 cup of fruit juice.

• two to three servings of milk, yogurt, or cheese. One serving equals 1 cup of milk or yogurt, 1 1/2 ounces of natural cheese (such as Cheddar), or 2 ounces of processed cheese (such as American). Choose low-fat or fat-free products most often.

• two to three servings of meat, poultry, fish, dry beans, eggs, or nuts. One serving equals 2 to 3 ounces of cooked lean meat, poultry without skin, or fish. Eat no more than 5 to 7 ounces per day. One half cup of cooked dry beans, one egg, or 1/2 cup of tofu counts as 1 ounce of meat. Two tablespoons of peanut butter or 1/3 cup of nuts counts as 1 ounce of lean meat.

The larger number of servings is for active men. A smaller number of servings are needed for women, inactive persons, or those trying to lose weight.

The NIH states that even modest amounts of physical activity can improve a person's health. Starting with small, specific goals such as walking 10 minutes a day, three days each week and slowly building up from there is recommended. An activity log may be kept to track progress.

The NIH suggests these activities to add more movement to daily life:

• Take the stairs instead of the elevator. Make sure the stairs are well lit.

• Get off the bus one stop early if you are in an area safe for walking.

• Park the car farther away from entrances to stores, movie theaters, or your home.

• Take a short walk around the block with family, friends, or coworkers.

• In bad weather, walk around a mall.

• Rake the leaves.

• Visit museums, the zoo, or an aquarium. You and your family will walk for hours and not realize it.

• Wash the car.

• Take a walk after dinner instead of watching TV.

Always consult your physician for a diagnosis.