WEDNESDAY, June 28, 2017 (HealthDay News) -- As more young adults are hospitalized for stroke each year in the United States, new research from Sweden hints at a reason why: Teens who become overweight during adolescence appear to face a higher stroke risk later.
"According to our results, avoiding excessive BMI increase between 8 and 20 years of age would lower the risk of stroke and cardiovascular diseases," said study author Dr. Jenny Kindblom, of the University of Gothenburg. BMI, or body mass index, is a measure of body fat.
The investigators noted that excessive weight gain during puberty may lead to elevated blood pressure, a strong risk factor for stroke.
"We see a strong association between BMI change during puberty and a diagnosis of hypertension [high blood pressure]," said study co-author Dr. Claes Ohlsson, from the same university.
Overall, stroke rates in the United States have declined significantly during the past five decades, according to the American Heart Association. But research published recently in the journal JAMA Neurology showed that hospitalizations for stroke among young adults have been climbing steadily since 1995.
Meanwhile, the problem with childhood obesity is widespread. The percentage of children who are considered obese in the United States has more than tripled since the 1970s, according to U.S. Centers for Disease Control and Prevention. Today, about 1 in 5 five school-aged children is obese.
For the Swedish study, scientists reviewed the health records of more than 37,600 males whose BMI was recorded at age 8 and again at age 20. They were tracked for an average of 38 years, starting at age 20. A total of 918 suffered strokes.
Compared to those who experienced average weight gain, those who became overweight or obese during puberty had an 80 percent greater chance of having a stroke. For males who started out overweight at age 8 and remained overweight at age 20, stroke risk was 70 percent higher.
Each 2-point hike in BMI was linked to a 20 percent rise in stroke risk. For example, a 5-foot-9-inch male at age 20 weighing 169 pounds has a BMI of 25, but a jump in weight to 183 pounds brings his BMI up to 27.
Kindblom said the study did not prove that weight gain caused the increased risk in stroke, it only showed an association.
And the researchers stressed that the kids who started out heavy but reached a normal weight by age 20 did not have any higher likelihood of stroke.
"This means that being overweight at age 8 does not in itself carry an extra risk of stroke," said Kindblom. "The increased risk of stroke is instead associated with being overweight at 20."
Dr. Sarah Samaan, a cardiologist at the Heart Hospital at Baylor in Plano, Texas, found it encouraging that taking steps to lose weight early in life might reduce the likelihood of having a stroke later.
"Kids are very resilient, and when problems are addressed at an early age, we can often avoid long-term consequences," she said. "In adulthood, that is less likely, as it is harder to reverse the consequences of an unhealthy lifestyle.
"This study gives strong credence to the argument that we need to fight for healthier meals and more physical activity for our kids, both at home and at school," said Samaan.
She advised young people who have weight problems to see a physician skilled in preventive care and to treat high or borderline-high blood pressure readings seriously.
The study was published online June 28 in Neurology.
SOURCES: Jenny Kindblom, M.D., and Claes Ohlsson, M.D., University of Gothenburg, Sweden; Sarah Samaan, M.D., cardiologist and physician partner, Heart Hospital at Baylor, Plano, Texas; June 28, 2017, Neurology, online