Seventeen-year-olds with above-average weight face a higher risk of cardiovascular disease in their 40s, but adolescent weight doesn't seem to affect the subsequent risk of diabetes, according to a new long-term study of Israeli army personnel.
Teens who were in the highest decile for body-mass index were nearly seven times more likely to develop coronary artery disease than those in the lowest decile - and the effect was even seen among youth who would not be considered overweight.
"We were surprised that it became significant well within the normal range with a BMI of 21 to 22," co-authorDr Iris Shai of Ben-Gurion University in Beer-Sheva said.
The study, in the New England Journal of Medicine, was an attempt to see if adolescent weight influenced health risks later in life, the way adult obesity does.
The data came from a database of 37,674 young men, all apparently healthy, who served in the military beyond their term of mandatory service and received primary care at military clinics.
During the follow-up period, which began at age 25 and averaged just over 17 years, 1,173 were diagnosed with diabetes and 327 were found to have coronary heart disease, defined as angiography-proven stenosis of more than 50% in at least one coronary artery.
Body mass index studied
When they stratified the men into deciles based on body mass index, they found that being in the highest BMI groups during adolescence posed the greatest risk for diabetes and heart disease.
But when they adjusted for the fact that men with higher BMI at baseline were more likely to be smokers, to exercise less, and to have a family history of heart disease and diabetes, as well as for other factors, only adult weight predicted diabetes risk.
Yet for coronary artery disease, an association could be seen with the man's weight when he was 17 years old.
The findings mean that doctors "should remember that history counts," Dr Shai said. "If you have a thin patient when he's 30, you would like to know his history because if he was heavier when he was 17, there is some (risk) for coronary heart disease."
On the other hand, she said, "If you were heavier when you were 17 and you lose weight when you are 30, you significantly decrease your risk for diabetes. That's the good news."
"The natural history of coronary heart disease (in contrast with that of diabetes) is probably the consequence of gradually increasing atherosclerosis during adolescence and early adulthood that leads to clinically important disease in midlife," concludes the research team.
The authors say their work may help redefine what constitutes a healthy BMI among adolescents and how it influences different diseases, at least among males. .(Reuters Health/ March 2011)