High Adolescent BMI Increases Stroke Risk in Young Adults With, Without Diabetes

Stroke. Colored angiogram of the brain of a 48 year old patient after a massive cerebrovascular accident (CVA), or stroke. There are fewer blood vessels visible compared to normal (see image M136/0347). This is due to a blocked middle cerebral artery causing areas of ischemia (lack of blood flow) to parts of the brain. The blockage may be due to a thrombus (blood clot) or embolism (air bubble or loose blood clot). Strokes can be instantly fatal, or may pass unnoticed. Symptoms can include muscle weakness, behavioral changes or paralysis. Angiograms use a contrast dye to highlight blood vessels.
The association between stroke and obesity in adolescence was examined in a population-based study.

A high body mass index (BMI) in adolescence is associated with ischemic risk in young adults with and without diabetes, according to findings published in Stroke.

Many Western countries have seen a rise in both the prevalence of adolescent obesity and stroke incidence among young adults, but the association between the two is uncertain. To assess this possible association, investigators analyzed data from a nationwide Israeli population-based study of 1,900,384 adolescents (58% boys; mean age, 17.3 ±0.5 years) who had been evaluated between 1985 and 2013, before mandatory military service.

BMI classification was determined by US Center for Disease Control and Prevention percentiles. Cox proportional hazard models were applied. The primary study outcome was first stroke event recorded by the Israeli National Stroke Registry between 2014 and 2018.

A total of 1088 first stroke events were found (167 hemorrhagic and 921 ischemic; mean age of diagnosis, 41.0 years). A significant association was seen between adolescent BMI and a graded increase in risk for any stroke and ischemic stroke, but less for hemorrhagic stroke.

After adjustments were made for age and sex, hazard ratios for first ischemic stroke event were 1.4 (95% CI, 1.2-1.6) for the 50th to 84th percentile group, 2.0 (95% CI, 1.6-2.4) for the overweight group, and 3.5 (95% CI, 2.8-4.5) for the obese group. The results remained almost the same when further adjusted for sociodemographic confounders.

When further adjustments for diabetes status were made, the hazard ratios were 1.3 (1.1-1.5) for the 50th to 84th percentile group, 1.6 (1.3-2.0) for the overweight group, and 2.4 (1.9-3.1) for the obese group. Results persisted when data were divided according to diabetes status, and ischemic stroke before age 30 was used as the outcome.

The study was limited by the investigators being unable to include data on lifestyle factors that may mediate the BMI-stroke association, such as physical activity, smoking, and adult-onset of obesity-related disturbances other than diabetes.

Nevertheless, study investigators concluded that “increased adolescent BMI was strongly associated with increased risk for ischemic but less so with hemorrhagic stroke in young adults, which was evident before age 30 in both sexes”.


Bardugo A, Fishman B, Libruder C, et al. Body mass index in 1.9 million adolescents and stroke in young adulthood [published online May 13, 2021]. Stroke. doi:10.1161/STROKEAHA.120.033595