Wednesday 18 December 2013

Healthy Obesity: Is It a Myth?

By Lisa Collier Cool


A new research review, published online in the Annals of Internal Medicine, seems to dispel the myth that it’s possible to be both obese and healthy if an individual has normal metabolic markers, like low cholesterol and low blood pressure.
The review, conducted at the Lunenfeld-Tanenbaum Research Institute at Toronto’s Mount Sinai Hospital, analyzed eight previous studies from the past decade. Researchers concluded that obesity consistently carries a higher risk of cardiovascular issues and premature death.

“The finding of increased risk of death or cardiovascular events for obese individuals suggests that gaining excess weight is associated with risk that may accumulate over time, even before metabolic and cardiovascular signs become apparent in lab tests,” study co-author Ravi Retnakaran, MD, MSc, FRCP(C), said in a news release.

Metabolic markers not the right measure

The eight studies analyzed by Mount Sinai researchers each spanned 10 years or more and included a combined 61,386 adults. Approximately nine percent of the participants studied were considered obese but metabolically healthy. In other words, those individuals had normal cholesterol levels, as well as blood pressure and blood sugar readings within the healthy range.
However, despite the normal metabolic readings, the review found that an obese person had a 24 percent higher risk of experiencing cardiovascular events (like a heart attack or stroke) or premature death compared to an individual with normal weight. A person who was overweight, but not obese, had a 21 percent greater risk.
“[W]e found that obesity stood out as the key risk factor for premature death from any cause, including cardiovascular events,” study co-author Bernard Zinman, MD, Senior Investigator at the Lunenfeld-Tanenbaum Research Institute, said in the release. “That’s true for obese people with so-called healthy metabolic status as well as obese people with poor metabolic status.”
That’s an important finding from a policy perspective, says the study’s lead author,  Caroline Kramer, MD, PhD, a post-doctoral fellow at the Institute. The notion that health care resources don’t need to be directed toward obese individuals whose lab tests are ‘normal’, she says, is simply mistaken.
“Our message to physicians is that for obese individuals, normal metabolic status regarding blood pressure, cholesterol and blood glucose is not protective,” Dr. Kramer notes in the release. “If they can start to lose weight, that’s a benefit.”

Obesity and health risks

Researchers have debated whether obese people who appear to be metabolically healthy would benefit from medical treatment.
However, this new research may be a step toward putting that debate to rest. One of the strengths of the latest research review was the length of the studies included. The risks for premature death became even more pronounced after 10 years of follow-up (the mean follow-up period of the eight studies was 11.4 years). Studies which suggested otherwise, Dr. Zinman told The Toronto Star, simply did not track people long enough.
Being overweight or obese carries numerous health risks, from back pain, sleep apnea, depression and asthma, to heart disease, stroke, cancer, and diabetes. According to recent statistics from the Centers for Disease Control and Prevention (CDC), more than two-thirds of American adults aged 20 and up are overweight, and roughly 36 percent are obese.
“We are telling people and doctors that it is not okay to be obese, even though you don't have metabolic abnormalities,” Dr. Kramer told CTV News. “This excess of weight still confers increased risk for cardiovascular events.”
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