Expanding Waistlines and Link to Metabolic Syndrome

Gisele Galoustian wrote . . . . .

For decades, American waistlines have been expanding and there is increasing cause for alarm. Researchers from the Charles E. Schmidt College of Medicine at Florida Atlantic University make the case that metabolic syndrome — a cluster of three of more risk factors that include abdominal obesity, high triglycerides, high blood pressure, abnormal lipids, and insulin resistance, a precursor of type 2 diabetes — is the new “silent killer,” analogous to hypertension in the 1970s. As it turns out, the “love handle” can be fatal.

In a commentary published in the Journal of Cardiovascular Pharmacology and Therapeutics , the authors describe how being overweight and obesity contribute to metabolic syndrome, which affects 1 in 3 adults and about 40 percent of adults aged 40 and older. Clinicians have traditionally evaluated each of the major risk factors contributing to metabolic syndrome on an individual basis. There is evidence, however, that the risk factors are more than just the sum of their parts.

“The major factor accelerating the pathway to metabolic syndrome is overweight and obesity,” said Charles H. Hennekens, M.D., Dr.P.H., the first Sir Richard Doll Professor and senior academic advisor to the dean who senior authored the paper with Dawn H. Sherling, M.D., first author and an assistant professor of integrated medical science, and Parvathi Perumareddi, D.O., an assistant professor of integrated medical science, all faculty members in FAU’s Charles E. Schmidt College of Medicine. “Obesity is overtaking smoking as the leading avoidable cause of premature death in the U.S. and worldwide.”

For optimal health, the waist should measure less than 40 inches for men and 35 inches for women. The authors explain that the visceral fat component of abdominal obesity leads not only to insulin resistance but also to the release of non-esterified free fatty acids from adipose tissue or body fat. Lipids then accumulate in other sites such as the liver and muscle, further predisposing individuals to insulin resistance and dyslipidemia — abnormal amounts of lipids. In addition, adipose tissue may produce various adipokines that may separately impact insulin resistance and cardiovascular disease risk factors.

The authors further caution that individuals with metabolic syndrome are largely asymptomatic but have a 10-year risk of a first coronary event, based on the Framingham Risk Score of 16 to 18 percent, which is nearly as high as a patient who already has experienced a prior coronary event. Moreover, they are concerned that metabolic syndrome is both underdiagnosed and undertreated.

“Visceral fat and its clinically more easily measured correlate of waist circumference are gaining increasing attention as strong predictors of metabolic syndrome even if you remove body mass index from the equation,” said Sherling. “There are patients who have a normal body mass index yet are at high risk. These patients represent an important population for clinicians to screen for metabolic syndrome.”

In the commentary, the authors emphasize the importance of therapeutic lifestyle changes beginning in childhood. They note that as the current generation of American children and adolescents reach middle age, morbidity and mortality from cardiovascular disease will increase.

“The pandemic of obesity, which begins in childhood, is deeply concerning,” said Perumareddi. “Adolescents today are more obese and less physically active than their parents and already have higher rates of type 2 diabetes. It is likely that the current generation of children and adolescents in the U.S. will be the first since 1960 to have higher mortality rates than their parents due mainly to cardiovascular disease, including coronary heart disease and stroke.”

The authors stress that obesity is a major risk factor for several cancers, especially colorectal, but also breast and prostate and that clinicians should not let the perfect be the enemy of the possible. For American adults, this implies the need for evidence-based doses of drugs of lifesaving benefit for those at high risk.

“In the U.S., cardiovascular disease will remain the leading killer due largely to obesity and physical inactivity,” said Hennekens. “Unfortunately, most people prefer prescription of pills to proscription of harmful lifestyles. The totality of evidence indicates that weight loss of 5 percent or more of body weight combined with a brisk walk for 20 or more minutes daily will significantly reduce cardiovascular events and deaths.”

According to the U.S. National Institutes of Health, approximately two-thirds of adults age 20 or older are overweight or obese with body mass indexes (BMI) greater than 25, and nearly one-third have BMIs greater than 30. Less than one-third of them are at a healthy weight with a BMI of 18.5 to 24.9. Estimated medical costs of obesity are as high as $147 billion a year for 2008, or almost 10 percent of all medical spending.

The authors also conclude that the export of American diet and lifestyle, which increases rates of obesity and physical inactivity, together with the alarming rates of export of tobacco to developing countries are resulting in cardiovascular disease emerging as the leading killer worldwide.

Source: Florida Atlantic University


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Waistline May Predict Heart Disease Better Than Weight

When it comes to heart health, new research adds to the argument that a pear-shaped body, which is heavy in the hips, may be better than an apple-shaped body, which carries more weight around the belly.

A study of diabetes patients found that increasing waist size appears to be a stronger predictor of serious heart disease than body weight or body mass index (BMI, the weight-to-height ratio).

“We have known that abdominal obesity is more linked to coronary atherosclerosis [plaque buildup in the arteries] than other forms of obesity,” said Dr. Brent Muhlestein, a study author and co-director of research at the Intermountain Medical Center Heart Institute in Salt Lake City.

“We found that left ventricle heart function got worse with progressive waist circumference. The relation between left ventricle function and waist circumference remained highly significant, even after adjusting for body weight,” Muhlestein said.

The left ventricle is the heart’s primary pumping chamber, and abnormal ventricular function is a common cause of heart disease, including congestive heart failure, the study authors noted.

Muhlestein added that reducing your waist size may reduce your risks.

For this investigation, scientists measured waist circumference, total body weight and BMI in 200 men and women with type 1 or type 2 diabetes. Diabetes can raise heart risks, but patients did not start the study with any symptoms of heart disease.

The researchers evaluated the heart function of study participants by using echocardiography — a type of ultrasound. They noted that left ventricular function got progressively worse as waist sizes got bigger, with heart decline eventually leveling off at 45 inches of waistline.

The study authors noted that the link between waist circumference and reduced heart function was independent of total body weight and BMI.

Dr. Sarah Samaan, a cardiologist and physician partner at the Heart Hospital at Baylor in Plano, Texas, said these results support previous research indicating that fat in the abdominal area is much more risky than fat elsewhere in the body.

“Abdominal fat produces a wide range of inflammatory substances, and is more highly correlated with heart disease, high blood pressure and diabetes than other types of fat,” said Samaan, who was not involved with the study. “We know that heavier people are more likely to have stiffer hearts, which in turn can predispose to heart failure. This study shows us that fat in the abdominal area is especially harmful to heart function.”

When compared to men, women in the study in general had better heart function at each increasing level of abdominal obesity. “In general, abdominal obesity had a greater adverse effect on men than women,” Muhlestein said.

He said women are advised to maintain a waist size of about 34 inches or less, while men should try to keep their waist circumference at 40 inches or less.

Previous research from the same team of scientists at Intermountain Medical Center Heart Institute and Johns Hopkins Hospital in Baltimore showed that the greater your BMI, the greater your risk of heart disease.

Exercise and diet remain the mainstays of treatment for all obese persons, including those with an apple shape, said Muhlestein. “This study emphasizes, however, that those of us who have an apple shape should perhaps be even more motivated to reduce all of our cardiovascular risk factors, including our waist circumference,” he said.

Samaan added that aerobic exercise is the best type of exercise to burn belly fat.

“While crunches may strengthen the abs, they won’t necessarily burn abdominal fat,” she said. “Also, smokers tend to hold more belly fat, even if their total body weight is normal, so quitting smoking may help.”

The report was to be presented at the annual meeting of the American College of Cardiology, in Chicago. Until published in a peer-reviewed medical journal, data and conclusions presented at meetings are usually considered preliminary.

Source: U.S. Department of Health and Human Services


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