The results contradict recent research suggesting a subgroup of
obese individuals known as “metabolically healthy obese” may not
face an increased risk for obesity-related complications such as
heart or kidney disease, researchers write in the Journal of
Clinical Endocrinology and Metabolism.
“People have a general understanding now that it is not unhealthy to
be overweight or obese as long as your lifestyle is relatively
healthy,” said senior study author Kristine Faerch of the Steno
Diabetes Center in Copenhagen.
“But overweight and obesity is associated with a high risk of
developing type 2 diabetes and cardiovascular disease,” she told
Reuters Health by email. “Maintaining a healthy weight through life
is important to lower risk.”
Faerch and colleagues analyzed data for more than 6,200 men and
women who participated in a large Danish study and were followed for
at least 10 years.
They looked at participants’ starting body mass index (BMI), a
measure of weight relative to height. BMI of less than 24.9
kilograms per square meter was considered normal weight, BMI of 25
to 29.9 was considered overweight and BMI of 30 or above was
considered obese. Someone 5 feet 9 inches tall and weighing 210
pounds, for example, would have a BMI of 31.
The researchers also looked at four heart disease risk factors at
the beginning of the study and at periodic follow-ups: low HDL ("good")cholesterol,
and elevated blood pressure, triglycerides and blood sugar.
Metabolically healthy individuals were defined as having none of
these risk factors, and metabolically unhealthy individuals had at
During the follow-up period, 323 participants developed heart
disease. Men who started out metabolically healthy and obese had
three times the risk compared to metabolically healthy normal-weight
men. Metabolically healthy obese women had double the risk of their
Men who were metabolically healthy and overweight, but not obese, at
the outset had the same risk as healthy normal-weight men, and risk
was only slightly increased for metabolically healthy overweight
Researchers also factored into their calculations any changes in
metabolic health status over the course of the study. Just 58 men
and 114 women, or 3 percent of the study population, qualified as
“metabolically healthy obese” at the start. And 40 percent of these
became metabolically unhealthy during a five-year period.
“What this study shows, before even looking at outcomes, is how rare
a strictly healthy type of obesity is in the first place,” said
Joshua Bell of the University of Bristol in the UK, who wasn’t
involved with the Danish study. “(It's) about 1 in 10 obese adults,
and like we’ve found in previous studies, this status is often
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Bell and colleagues published research in the International Journal
of Obesity in February that suggests obesity also hastens
age-related functional decline and disability, even in metabolically
“As important as heart disease is, it’s not the only aspect that can
go wrong,” he said. “We also need to consider musculoskeletal
impairments and other outcomes that affect quality of life,” he told
Reuters Health by email.
Bell’s team found that during two decades of aging, physical
function declined two times more and body pain increased six times
more in so-called healthy obese adults compared to normal-weight
“This will become increasingly important as more people live with
obesity for longer as we get better at controlling heart disease,”
Future research may also focus on different definitions of
metabolically healthy obesity, said Matthias Schulze at the German
Institute of Human Nutrition in Potsdam-Rehbruecke who wasn’t
involved with either study. Instead of body mass index, measurements
could use waist circumference, waist-hip ratio or body fat
distribution, he noted.
“We know now that the healthy state can change to the unhealthy
state quickly over the course of a few years,” Schulze said by
email. “The question now is - what can we do to reduce risk in both
SOURCE: http://bit.ly/2nbYpIz Journal of Clinical Endocrinology and
Metabolism, online March 7, 2017; and http://go.nature.com/2nsge8F
International Journal of Obesity, online February 21, 2017.
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