Research Highlights:
Embargoed until 4 a.m. CT/5 a.m. ET, Thursday, June 6, 2024
DALLAS, June 6, 2024 — In an analysis of more than 50 years of health data, women who had overweight or obesity at age 14 or 31 were more likely to have an ischemic (clot-caused) stroke before age 55, according to research published today in Stroke , the peer-reviewed scientific journal of the American Stroke Association, a division of the American Heart Association.
According to the American Heart Association, an ischemic stroke occurs when a vessel supplying blood to the brain is obstructed. Ischemic stroke is the most common type of stroke and accounts for about 87% of all strokes.
The study conducted in Finland suggests that women with overweight at age 14 were associated with later clot caused stroke risk despite having lost weight by age 31. Also, women with overweight at age 31 were associated with later clot caused stroke risk despite having been normal weight at age 14. An increased risk of clot caused stroke was not found in men who were overweight at ages 14 or 31. However, men with obesity at age 31 had a higher risk of bleeding stroke compared to women with obesity at age 31.
“Our findings suggest that being overweight may have long-term health effects even if the excess weight is temporary,” said lead study author Ursula Mikkola, B.M., an investigator in the Research Unit of Population Health at the University of Oulu in Finland. “Health care professionals should pay attention to overweight and obesity in young people and work with them to develop healthier eating patterns and physical activity. However, conversations with teens and young adults about weight should be approached in a non-judgmental and non-stigmatizing manner.”
To analyze the association between weight at different ages and the risk of stroke before age 55, the researchers reviewed long-term data from participants in the Northern Finland Birth Cohort 1966. The Northern Finland study group was initiated to help understand factors related to preterm birth and infant deaths. In 1966, more than 12,000 pregnant women were enrolled from two northern provinces in Finland. More than 10,000 offspring, now in their 50s, have been followed ever since, with their health information used in multiple research studies.
For this analysis, researchers used the body mass index (BMI), a ratio of weight to height, to explore whether those who were overweight or obese at age 14 or age 31 had a different risk of early stroke compared to peers who were not overweight or obese at age 14 or 31. About 1 in 20 participants experienced a clot-caused stroke or transient ischemic attack (TIA, or mini-stroke) during the average follow-up period of almost 39 years after the age 14 evaluation and almost 23 years after the age 31 evaluation. The current study’s analysis ended in 2020.
Assessing the impact of periods of excess weight on stroke risk, the researchers found:
It is important to note that weight is not the only health factor that impacts stroke risk. Many other factors affect stroke risk and should be considered in addition to weight. “By living a healthy lifestyle (eating better, not smoking, healthy sleep, managing blood pressure, cholesterol and blood glucose levels, avoiding excess alcohol use and being physically active), you can lower your risk of stroke even if you were overweight when you were younger,” Mikkola added.
Researchers do not know why the association of increased risk for clot-caused stroke was not found in men. Researchers are currently investigating the potential causes as well as other risk factors in more detail.
In an accompanying editorial Larry Goldstein, M.D., FAHA, notes, “This study provides additional evidence of an association between overweight/obesity and stroke in young adults. However, while it is tempting to assume that reductions in overweight/obesity in younger populations would translate to lower stroke rates in young adults, this remains to be proven.” Goldstein is an American Heart Association Stroke Council member and chair of the department of neurology and co-director of the Kentucky Neuroscience Institute, University of Kentucky HealthCare in Lexington, Kentucky.
Study details, background and design:
Limitations of the study include that it is an analysis of health data (an observational study) and, therefore, it cannot prove a cause-and-effect relationship between weight and early stroke risk. Participants were all born in Finland, so the results may not be generalizable to people in other countries.
“Stroke at a young age is rare, so the difference of just a few strokes could have an outsized impact on the risk estimates,” Mikkola said. “Also, BMI relies solely on a person’s height and weight, therefore, a high BMI may be a misleading way to define obesity, especially in muscular people who may carry little fat even while weighing more.”
Co-authors, disclosures and funding sources are listed in the manuscript.
Studies published in the American Heart Association’s scientific journals are peer-reviewed. The statements and conclusions in each manuscript are solely those of the study authors and do not necessarily reflect the Association’s policy or position. The Association makes no representation or guarantee as to their accuracy or reliability. The Association receives funding primarily from individuals; foundations and corporations (including pharmaceutical, device manufacturers and other companies) also make donations and fund specific Association programs and events. The Association has strict policies to prevent these relationships from influencing the science content. Revenues from pharmaceutical and biotech companies, device manufacturers and health insurance providers and the Association’s overall financial information are available here .
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About the American Stroke Association
The American Stroke Association is devoted to saving people from stroke — the No. 2 cause of death in the world and a leading cause of serious disability. We team with millions of volunteers to fund innovative research, fight for stronger public health policies and provide lifesaving tools and information to prevent and treat stroke. The Dallas-based association officially launched in 1998 as a division of the American Heart Association. To learn more or to get involved, call 1-888-4STROKE or visit stroke.org . Follow us on Facebook , X .
Stroke
Overweight in Adolescence and Young Adulthood in Association With Adult Cerebrovascular Disease: The NFBC1966 Study