Body Fat More Reliable Measure of Heart Disease Risk
Than Obesity, BMI
Normal Weight Not Safe Zone for Heart, Metabolic
Problems
March
28, 2008 – So you finally did it – you reduced your weight to the
“normal” level. Now the Mayo Clinic has some bad news for you. More than
half of American adults considered to have normal body weight in America
have high body fat percentages - greater than 20 percent for men and 30
percent for women - as well as heart and metabolic disturbances.
The finding conflicts with the widely held belief
that maintaining a normal weight automatically guards against disorders
such as high levels of circulating blood fats and a tendency to develop
metabolic syndrome, which often leads to type 2 diabetes.
The researchers defined “normal weight” by body
mass index (BMI). They found that people with normal BMI who had the
highest percentage of body fat were also those who had metabolic
disturbances linked to heart disease.
The researchers use the phrase “normal weight
obesity” to describe this new type of patient at risk for metabolism
problems and risk factors for heart disease, but who rates as “normal”
on standard weight charts.
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They defined normal weight obesity as a condition
of having a normal BMI with high body fat percentage. The Mayo team will
present its study results at the American College of Cardiology’s Annual
Scientific Session next week in Chicago.
“Using the term ‘normal weight obesity’ is really a
way of being more precise about the changing conceptualization of
obesity, because the real definition of obesity is excess body fat,”
says Francisco Lopez-Jimenez, M.D., a cardiologist on the Mayo research
team.
Study finds Body Mass Index not the best indicator
of mortality
August 8, 2006
“Our study demonstrates that even people with
normal weight may have excessive body fat, and that these people are at
risk for metabolic abnormalities that lead to diabetes and, eventually,
to heart disease.”
Significance of the Mayo Clinic Study
Heart disease remains the major cause of death and
disability in westernized countries. Researchers around the world are
striving to refine the relationship of body composition to heart health
as a means of:
● Designing more effective risk assessment tools
● Improving public health programs for reducing risk
● Designing new and better clinical rehabilitation programs for heart
patients
While a focus on maintaining “a healthy weight” has
long been a centerpiece of these efforts, Mayo’s new study suggests the
focus may need to shift.
Instead of tracking weight and BMI only, public
health measures to prevent heart disease might benefit more from
measuring the belly or by assessing percentage of body fat as more
reliable risk factors of heart disease.
Mayo studies in 2006 and 2007 suggested this
criterion by demonstrating the inability of BMI to discriminate between
body fat and lean muscle.
“Combined, the data from our earlier work and the
current study suggest it’s time for a new measure of body fat as a risk
factor of heart disease,” says Dr. Lopez-Jimenez.
About the Study
The researchers studied 2,127 adults, equally
divided between men and women, who had normal weight (BMI between 18.5
and 24.9 units). The participants’ body composition was assessed, and
their risk factors for metabolic and heart disease were collected by the
U.S. government in its
Third National Health and Nutrition Examination Survey.
From this data, researchers found that normal
weight obesity appears to be highly prevalent, affecting more than half
of patients with a normal weight as defined by the BMI. After
controlling for age, sex and race, normal weight obesity subjects had
significantly higher rates of several alterations in blood chemistry
that can negatively affect heart and metabolism health. These markers of
disregulation include:
● Altered blood lipid profile, such as cholesterol
● High leptin, a hormone found in fat and other tissues and is
involved in appetite regulation
● Higher rates of metabolic syndrome
● Collaboration and Support
Other Mayo Clinic team members include Abel
Romero-Corral, M.D.; Simona Boarin, M.D.; Justo S. Johnson; Virend K.
Somers, M.D., Ph.D., all from Mayo’s campus in Rochester, Minn. Their
work was supported by Mayo Foundation for Medical Education and Research
and the American Heart Association.
To obtain the latest news releases from Mayo
Clinic, go to www.mayoclinic.org/news. MayoClinic.com (www.mayoclinic.com)
is available as a resource for your health stories. For more on Mayo
Clinic research, go to
www.mayo.edu.
Keep up with the latest news for senior citizens, baby
bommers
March
28, 2008 – So you finally did it – you reduced your weight to the
“normal” level. Now the Mayo Clinic has some bad news for you. More than
half of American adults considered to have normal body weight in America
have high body fat percentages - greater than 20 percent for men and 30
percent for women - as well as heart and metabolic disturbances.
Obesity,
But Not Overweight, Linked To Cancer and Cardiovascular Deaths –
