Coronary Artery 311.
(photo credit: Creative Commons)
Seventeen-year-olds whose body mass index (BMI) is today considered at a
somewhat-elevated- but-normal level are at a substantial risk of obesity-related
disorders – including heart disease – in young adulthood, according to a new
Ben-Gurion University Faculty of Health Sciences- Sheba Medical Center study
that followed up 37,000 youngsters the year before being conscripted into the
The important research, which with more evidence could lead
nutritionists, endocrinologists, pediatricians and other specialists to rethink
their assessments of risk factors, was published on Thursday in the prestigious
New England Journal of Medicine.
BMI, calculated easily (free BMI
calculator sites are on the Internet) as weight in kilograms divided by the
square of height in meters, is a well-accepted indicator of normal weight,
overweight and obesity. A BMI between 18.5 and 25 is considered normal, while
between 25 and 30 is overweight and minor obesity; between 30 and 35 is
unhealthy obesity; and over that extremely unhealthy, morbid obesity.
study was conducted by a joint research team led by endocrinology researcher
Assaf Rudich and nutritionist and epidemiology Prof. Iris Shai of
BGU and Dr. Amir Tirosh, an endocrinologist at Sheba’s Talpiot program and
Brigham and Women’s Hospital-Harvard Medical School.
They found that
baseline BMI at adolescence can help predict the early occurrence not only of
heart disease in young adulthood but also of type 2 diabetes, which is usually
predicted mainly by recent BMI rises and weight gain in adulthood and not
examining the adolescent BMI.
For heart disease, both elevated BMI in
adolescence and recent BMI levels as a young adult are independent risk
Rudich told The Jerusalem Post they found elevated BMI has a
“distinctive relationship” with obesity-related coronary heart disease and
diabetes in adults between the age of 30 and 40.
The large cohort study
was made possible by following 37,000 male pre-IDF conscriptees through young
“I can’t say that BMI norms have to be reassessed now. It is
very complex, and one observational study can’t do it. More work, including
interventional studies [in which there are lifestyle and behavior changes] has
to be done, but these are important findings that raise many
He noted that the NEJM published a Norwegian study in 2007 on
BMI in childhood but it could not compare with the new Israeli research, which
followed up people through their 30s and 40s.
“It is well established,”
he said, “that an obese teenager is likely to become an obese adult, and an
obese adult has an elevated risk of developing type 2 diabetes and/or heart
disease from start of his 50s.”
What has been unknown is whether BMI at
adolescence is a risk factor for the two diseases even if the teenager is not in
the obese range and if this is associated with BMI at adolescence independent of
BMI at adulthood.
Coronary heart risk in young adulthood has rarely been
studied and certainly for not such long periods of follow-up, but the fact that
the IDF monitors the health of professional IDF officers made this
When professional soldiers were tested by the IDF every few
years, their BMI was found to rise at a rate 0.2 to 0.3 BMI units annually,
reaching an average weight gain of about 15 kilos between the ages of 17 and
The researchers were able to control for multiple risk factors for
both diseases, including age, fasting blood glucose, blood lipids, blood
pressure, smoking, exercise habits and family history.
They found that
every one-unit rise of BMI was associated with a 10 percent increased risk for
type 2 diabetes in early adulthood and a 12 percent increase in the risk for
heart disease. During the 17-year study period, 1,173 new cases of diabetes and
327 new cases of heart disease were diagnosed.
Women in the professional
army were not monitored for this study from age 17 because there are not enough
who remain so long as career army personnel, Rudich said. However, it is
worrisome also for women, as female conscriptees are known to gain more weight
than men during military service.
“Our results suggest that the obesity
problem in children and teens is likely just the tip of the iceberg for
increased risk for the occurrence of type 2 diabetes and heart disease in one’s
30s and 40s,” Tirosh said.
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