Having a higher-than-normal body mass index (BMI) as a teenager could be an indicator that men will experience heart failure in middle age. That’s according to findings published in the European Heart Journal based on a study of more than 1.6 Swedish enlisted soldiers between 1968 and 2005.

Researchers analyzed the BMIs of the men when they were required to join the Swedish military at 18 and compared those numbers to their health outcomes in middle age. They followed the men for between five and 42 years, for an average of 23 years. Controlling for other factors, the study showed that the men who had BMIs over 20 had a 16 percent increased risk of heart failure by age 47 for every increasing BMI point. That means the increasing risk applied even to men who had a BMI considered within the normal range of 18.5 and 25.

Study author Annika Rosengren of Sweden’s University of Gothenburg said she was surprised to discover even BMIs that are considered normal can mean a higher risk for heart failure. She speculated it might be because younger people are naturally smaller, and so even a slightly elevated BMI could have a significant impact on health. The study did not measure the subjects’ weight beyond their initial enlistment at 18, so it’s possible that a higher BMI as a teenager, even within normal range, could be an indicator of more weight gain as an adult. That weight gain years later could help explain the heart failure. Rosengren also pointed out that men tend to live with a higher risk of heart failure in general.

Given the large sample size of this study, Rosengren said the findings could hold important insights for public health and to curb high obesity rates worldwide.

“Action needs to be taken by governments as well as by individuals, for instance by creating an environment that does not promote overweight and obesity, and that encourages people not to be sedentary and not to eat more than they need. This is more important than hassling people into dieting whatever shape they are. Once established, overweight and obesity is much harder to tackle,” she said in a statement.