The findings call into question what's known as the
"obesity paradox," the belief that people with a normal weight are
more likely to die from type 2 diabetes than those who are
overweight or obese.
"There's been a pretty polarized debate over whether this is real or
not," lead author Deirdre Tobias, from the Harvard School of Public
Health in Boston, told Reuters Health. "I would like to believe that
this lays it to rest."
The results, she said, show that, "There is no benefit of being
overweight or obese. In fact, we see that, among nonsmokers at
least, being overweight and obese does increase your risk. It's not
Tobias and her colleagues analyzed data from two large, long-term
studies: the Nurses' Health Study, begun in 1976, and the Health
Professionals Follow-up Study, inaugurated in 1986. The new report
included more than 11,000 people in those studies who were diagnosed
with diabetes. None of them had cancer or heart disease at the time
Volunteers were followed for nearly 16 years, on average. During
that time, about 3,000 of them died.
The researchers found that people who were overweight or obese when
they were diagnosed with diabetes were between nine and 33 percent
more likely to die than those who were diagnosed while at the higher
end of normal weight. The risk was greatest among the heaviest
People diagnosed with diabetes before age 65 faced a higher risk as
their weight rose. In those 65 and over, the effect was less
pronounced, according to findings published Wednesday in the New
England Journal of Medicine.
Smoking was also linked to when people died. For instance, the
lowest-weight women with a history of smoking were more likely to
die during the study period than normal-weight women who smoked.
Risks then increased again at higher weights.
Among nonsmokers with diabetes, however, the trend was more direct:
The lower a person's weight, the lower the risk of early death.
[to top of second column]
"I thought it was interesting that being a thin smoker wasn't
healthy," Dr. Susan Spratt, a diabetes researcher from the Duke
University School of Medicine in Durham, North Carolina, told
"Smoking might keep your weight down, but you have more risk,"
Spratt, who was not involved in the new research, said. "Smoking
compounds all the obesity complications, whether it's diabetes or
One earlier study had concluded that people who had a normal
weight when they were diagnosed with diabetes were twice as likely
to die over a given period as overweight or obese people.
The researchers said one problem with past studies suggesting that
extra weight is protective in diabetes is that weight estimates were
often done decades after the diagnosis, which could skew the
"We were also able to control for smoking status better," Tobias
said. That's important because smokers tend to be leaner than
"Losing weight is beneficial, and you may not have to lose a lot,"
Spratt said. "But losing five percent or 10 percent of your body
weight if you are obese can help so many issues, from joint pain and
sleep apnea, to diabetes and diabetes complications."
Journal of Medicine, online Jan. 15, 2014.
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