New European research has found that for men, having a higher body mass index (BMI) at age 18 is linked with a higher risk of suffering a heart attack before age 65.
Carried out by researchers at the University of Gothenburg, Sweden, the new study looked at Swedish men born between 1950 and 1987 who enlisted for mandatory military service at the age of 18.
At enrollment, all the men -- 1,668,921 in total -- had to complete physical and psychological examinations which included measurements of BMI, blood pressure, IQ, and cardiovascular and muscular fitness.
They were then followed for up to a maximum of 46 years.
The findings, presented on Tuesday at ESC Congress 2019 together with the World Congress of Cardiology, showed that a higher BMI at age 18 was associated with a higher risk of a heart attack before age 65, even after taking into account age, year of conscription, any other health conditions at the start of the study, parent's education, blood pressure, IQ, muscle strength and fitness.
Perhaps surprisingly, the increase in risk started at BMI 20 kg/m2, a level considered normal.
It then then rose gradually, with those who were defined as severely obese -- a BMI of 35 or higher -- showing a nearly 3.5-fold higher likelihood of heart attack.
Study author Dr. Maria Aberg commented on the findings saying, "We show that BMI in the young is a remarkably strong risk marker that persists during life. Our study supports close monitoring of BMI during puberty and preventing obesity with healthy eating and physical activity. Schools and parents can play their part by encouraging teenagers to spend less leisure time in front of a screen and providing healthy food."
As to why the risk started to increase even at healthy BMIs, Dr. Aberg explained, "This is an exploratory, population-based study meaning we report associations, but can only speculate on mechanisms. It is possible that altered lipid metabolism, inflammation, and oxidative stress contribute to atherosclerosis at BMIs over 20. In addition, reference values for normal BMI in late adolescence may need to be reconsidered."
Dr Aberg noted that since the study only included men, the results may not be applicable to women, although she concluded that, "Our finding of a link between adolescent BMI and heart attack in adulthood supports our previous results for heart failure. As the prevalence of overweight and obesity in young adults continues to escalate, we may start to see correspondingly higher rates of heart attacks and strokes in the future. Urgent action is needed by parents, schools, and policy makers to halt the obesity epidemic in children and young people."