According to a newly published study by the New England Journal of Medicine, a high body mass index as a teenager increases the risk of heart disease as an adult. The study followed 37,674 young men for an average of 17.4 years and determined that heart disease is related to an increased BMI as a young adult. This was true even if the individual took measures to increase their health by lowering their BMI as they grew older. An obese teenager was seven times more likely to develop heart disease in his 30’s than a teenager who was not obese.
For every one unit increase in BMI in the teen years, the study found a 12 percent increase in the risk of heart disease around 20 years later. And, for every one unit increase in BMI, the study found a nearly 10 percent increase in the risk of type 2 diabetes, though this risk may largely be related to a higher BMI in adulthood as well.
"For teens with a BMI of 25, the risk of diabetes is about threefold higher than for people with the lowest BMI," said the study’s lead author, Dr. Amir Tirosh, a clinical and research fellow in the endocrine division at Brigham and Women’s Hospital and the Harvard School of Public Health in Boston.
"For cardiovascular disease, the risk was threefold higher at a BMI of 20.9, and sevenfold higher at a BMI of 25 or above," said Tirosh.
A normal BMI is 24.9 or lower; 25.0 is the threshold for being considered overweight.
The risk of later heart disease begins when BMI is well within what’s considered the normal range, said Tirosh. "A BMI of 20.9 means a 5’10" male would weigh 146 pounds," he added.
This was the first study of it’s kind to demonstrate a link between being overweight as a teenager and increased heart disease as an adult. It’s not clear exactly how this is accomplished in the body, but the study showed a statistically significant correlation between increased BMI as a teenager and heart disease as an adult.
The risk associated with diabetes did not increase significantly based upon an increased BMI as a teenager. If an overweight teenager lost weight over the risk of developing diabetes almost completely disappeared. The risk of diabetes was mainly associated with an increased BMI near the time a diagnosis of diabetes was made and those risks could be averted by losing weight and decreasing BMI.