Parents, take note: A nationwide, long-term study of 2.3 million Israeli adolescents conducted from 1967 through 2010 has found a link between elevated body mass index (BMI) in late adolescence and life-threatening heart disease in midlife.
BMI is the value derived from the weight and height of an individual (weight divided by the square of the height – kg/m2). Normal BMI values are considered to be in the range of 18.5 to 25.
One-third of adolescents are either overweight or obese
Overweight and obesity in adolescents have increased substantially in recent decades, and currently affect a third of the adolescent population in some developed countries.
Some studies suggest that an elevated BMI is associated with an increased risk of death from cardiovascular causes. However, a determination of the BMI threshold that is associated with increased risk of fatality has remained uncertain.
In light of the worldwide increase in childhood obesity, Israeli researchers Prof. Jeremy Kark and Dr. Hagai Levine from the Hebrew University of Jerusalem, together with Dr. Gilad Twig of Sheba Medical Center and other colleagues in Israel, set out to determine the association between BMI in late adolescence and death from cardiovascular causes in adulthood.
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Their study, which was recently published in the prestigious medical journal The New England Journal of Medicine, was based on the body mass index values of 2.3 people, starting at 17 year olds.
The results showed that 9.1 percent died from cardiovascular causes, including coronary heart disease, stroke, and sudden death. But those with elevated BMI had the highest risk. The BMI threshold associated with fatal risk was shown to be 22.5.
“Our findings appear to provide a link between the trends in adolescent overweight during the past decades and coronary mortality in midlife,” Kark said in a statement. “The continuing increase in adolescent BMI, and the rising prevalence of overweight and obesity among adolescents, may account for a substantial and growing future burden of cardiovascular disease, particularly coronary heart disease.”
The timing of exposure to obesity during a person’s lifetime may play an important role
How might adolescent BMI influence cardiovascular outcomes in adulthood? The researchers considered two possible pathways. First, obesity may be harmful during adolescence, since it has been associated with unfavorable metabolic abnormalities, increased blood pressure, impaired glucose metabolism and insulin resistance. Furthermore, the timing of exposure to obesity during a person’s lifetime may play an important role.
Second, BMI tends to track along the life course, so that overweight adolescents tend to become overweight or obese adults, and overweight or obesity in adulthood affects the risk of cardiovascular disease.
Scientists involved in this research are affiliated with the Department of Medicine and the Dr. Pinchas Bornstein Talpiot Medical Leadership Program, Sheba Medical Center; Israel Defense Forces Medical Corps; Sackler School of Medicine, Tel Aviv University; Hebrew University-Hadassah Braun School of Public Health and Community Medicine; Israel Ministry of Health; Department of Medicine, Mount Auburn Hospital; and Harvard Medical School. The study was funded by a research grant from the Environment and Health Fund in Jerusalem.