Having a higher body mass index (BMI) in adolescence is linked to greater risk of first ischaemic stroke in adults under age 50 — regardless of whether they had Type 2 diabetes.
The research was published in Stroke, a journal of the American Stroke Association, a division of the American Heart Association.
Although the prevalence of adolescent obesity and stroke among adults under the age of 50 years continue to rise around the world, the precise link between the two conditions is still not fully understood.
“Adults who survive stroke earlier in life face poor functional outcomes, which can lead to unemployment, depression and anxiety,” said study co-author Gilad Twig, MD, MPH, PhD, an associate professor in the Medical Corps of the Israel Defense Forces and the department of military medicine, Faculty of Medicine of The Hebrew University in Jerusalem, Israel. “The direct and indirect costs attributed to stroke prevention and care are high and expected to keep increasing since the rate of stroke continues to rise.”
This study examined adolescent BMI and first stroke before the age of 50 among 1.9 million participants (ages 16 to 20; 58% male) from two nationwide databases: the Israel Defence Forces and the Israeli National Stroke Registry. All the participants in the database had undergone one complete medical exam between 1985 and 2013.
Standard BMI groups are underweight (less than 5th percentile), low-normal BMI (5th to 49th percentile), high-normal BMI (50th to 84th percentile), overweight (85th to 94th percentile), and obese (greater than 95th percentile). Details on percentile BMI measures by gender are in the article.
Overall, 1088 strokes occurred (921 ischaemic strokes, 167 haemorrhagic strokes) during the follow-up period, a mean age of 41 when the stroke occurred. Adolescent BMI was directly related to the risk of first ischaemic stroke. Compared to participants in the low-normal BMI group, overweight adolescents had a 2-times higher risk of stroke before age 50, and obese adolescents had a 3.4-times higher risk.
Even adolescents with BMIs in the high-normal range were more likely to have a stroke before age 50 compared to those in the low-normal BMI group. Adolescents who were either overweight or obese still had a higher risk of stroke (1.6-times and 2.4-times, respectively) after accounting for Type 2 diabetes, compared to those with normal BMI.
Even though overweight and obesity during adolescence is a common problem, researchers were surprised to find that Type 2 diabetes did not explain the higher risk for ischaemic stroke, which in some cases occurred even before age 30.
Dr Twig noted that current literature shows that a stroke early in life may lead to recurrent stroke, heart attack, long-term care and premature death.
“Our findings underscore the importance of effective treatment and prevention of high normal and excessively high BMI during adolescence,” Dr Twig said. “Our study is also the first to show that the risk of stroke associated with higher BMI values is the same for both men and women.”
A major limitation of the study is that BMI data at follow-up were not available for all participants, meaning that researchers could not assess the contribution of obesity over time to stroke risk and to separate out the risk of BMI during adolescence.
Source: American Heart Association
Journal information: Bardugo A, Fishman B, Libruder C, et al. Body Mass Index in 1.9 Million Adolescents and Stroke in Young Adulthood. Stroke. 2021;STROKEAHA120033595. doi:10.1161/STROKEAHA.120.033595
