New Canadian research shows that obesity doesn’t necessarily doom people to an early grave.
Two research teams using a new tool called the Edmonton Obesity Staging System, which ranks the overweight and obese on a five-point scale according to their underlying health, have found that not only can the scale predict who is at greater risk of dying, but that otherwise healthy obese people live as long as those of “normal” weight, and are less likely to die of cardiovascular causes.
The back-to-back studies come as evidence mounts that a significant proportion of overweight people are metabolically healthy and that the risks associated with obesity do not make for a one-size-fits-all formula.
The Edmonton staging system grades obesity on a scale of zero to four. It uses physical measures such as BMI, or body mass index, as well as waist-to-hip ratios. But it goes further by taking into account the presence — or absence — of a spectrum of disease.
Under Stage 0, the person is obese, but has no apparent obesity-related health risks, meaning their blood pressure, blood fats and other risks are all within the normal range. The more underlying heath problems, such as diabetes, sleep apnea and heart failure, the higher the stage. Stage 1 obesity describes people with “sub-clinical” signs of trouble, such as borderline high blood pressure, elevated liver enzymes and occasional aches and pains. Stage 4 is the most severe. At Stage 4, patients have serious, “potentially end-stage” disabilities from obesity-related diseases.
In one study published Monday in the Canadian Medical Association Journal, University of Alberta researchers tested the system using data from a survey of 8,143 people in two U.S. national health and nutrition surveys.
They found that although 77 per cent of overweight or obese people in one survey, and 90 per cent of those in another were classified as Stage 1 or 2, their risk of dying over 20 years of followup was substantially lower than people classified as Stage 3 obesity.
After adjusting for age, history of smoking and metabolic syndrome — a cluster of conditions such as high blood pressure and diabetes —about two per cent of people with scores of O or 1 died during followup, compared to about 40 per cent of Stage 3 patients.
“That’s a huge difference,” said Dr. Arya Sharma, who first proposed the Edmonton classification system.
“What this actually means is if I examine people today and I see that they’re Stage 0 or Stage 1, I can tell them to eat as healthy and be as physically active as possible rather than running out and trying to lose weight,” said Sharma, chair of obesity research and management at the University of Alberta in Edmonton.
In a second study, using a modified version of the Edmonton scale, researchers led by York University’s Dr. Jennifer Kuk categorized 6,000 obese Americans according to the Edmonton obesity staging system and compared their risk of dying to 23,000 lean individuals over a 16-year span.
They found that obese people with no or only mild health problems had the same risk of dying over the followup period as normal-weight people. In fact, patients in Stage 0 or 1 were at lower risk of dying from cardiovascular disease or coronary heart disease than normal-weight individuals.
People with more severe scores were slightly older, had modestly higher BMIs, were more likely to be former smokers, lost more weight over their lifetime and lost more weight frequently. People with lower scores tended to be more physically fit.
“Our findings challenge the idea that all obese individuals need to lose weight,” Kuk said in a statement released with the study.
The study was published online in Applied Physiology, Nutrition and Metabolism.
Body mass index “only measures how big the patient is, not how sick the patient is,” says Sharma, founder of the Canadian Obesity Network who co-authored both papers.
When a person’s body mass index is above 30, “you’re clinically considered to have obesity,” says Sharma.
“But when you look at people who meet those BMI criteria, not all of them actually have any health problems.”
Sharma says weight-management interventions, including publicly funded bariatric or weight-loss surgery, where waiting lists can stretch years, should be targeted at the people who have the most to gain.
“Obesity treatment is always expensive and its not always easy to do,” Sharma said.
Currently, patients with a BMI over 40 are eligible for surgery, “but there are people with BMIs over 40 who are actually pretty healthy,” he said. “The question becomes, what’s the health benefit of doing that?”
The system is modelled after other staging systems used to determine how sick people are from diseases such as cancer or kidney failure.
“If someone comes to my office and their BMI is 35, they have obesity, there’s no question,” Sharma said.
“But if I do the tests and I find that they have no other risk factors, then I can confidently tell them that they are at extremely low risk of dying. There shouldn’t be an urgent need to lose weight just because their BMI is high. The focus really should be on trying to maintain that weight and not get heavier.”
The opposite could hold for people with lower BMI’s who don’t meet criteria for surgery but who are at high risk and should be treated. “And we’re missing those patients,” Sharma said.
Sharma said people who have a history of weight cycling — losing large amounts of weight only to put the weight back on, or more — appear to be at higher risk of obesity-related complications.
“If you’re constantly dieting and trying to lose weight, and you put it back and you diet again, you might actually be causing problems.”
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Sharon Kirkey’s “Heavy But Healthy? New Formula Slims Down Dangerously Obese” appears in the VANCOUVER SUN via canada.com.