Overweight teens, young adults face greater stroke risk later, study says

NEW YORK, June 6 (UPI) -- Women who harbor excess weight as teens or young adults may face a higher risk of a clot-caused stroke by age 55, while men do not, a new study finds.

The analysis, which spanned more than 50 years, was published Thursday in Stroke, the peer-reviewed scientific journal of the American Stroke Association, a division of the American Heart Association.

These findings are based on a study conducted in Finland that tracked more than 10,000 people from birth into their 50s.

A key finding was that losing excess weight after adolescence may not eliminate the risk of an ischemic stroke, researchers said.

This type of stroke occurs from obstruction of a vessel supplying blood to the brain. It's the most common type and accounts for about 87% of all strokes, according to the heart association.

Researchers suggested that health care professionals pay attention to excess weight and obesity in young people and promote healthy eating and physical activity from an early age.

"Stroke is a leading cause of disability and death worldwide, and identifying modifiable risk factors is crucial for developing effective prevention strategies," the study's lead author, Ursula Mikkola, an investigator in the Research Unit of Population Health at the University of Oulu in Finland, told UPI via email.

"Early intervention and prevention efforts could significantly reduce the long-term burden of stroke and improve overall cardiovascular health," Mikkola said.

Being an overweight female at age 14 was associated with later ischemic stroke risk, despite having lost weight by age 31. Also, being an overweight female at age 31 was associated with later ischemic stroke risk despite a normal weight at age 14.

Researchers did not find an increased risk of ischemic stroke in men who were overweight at ages 14 or 31.

To analyze the association between weight at different ages and stroke risk before age 55, researchers reviewed long-term data from the Northern Finland Birth Cohort 1966. This study group was started 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. Since then, investigators have followed more than 10,000 offspring, now in their 50s, with their health information used in multiple research studies.

For this analysis, researchers utilized body mass index -- a ratio of weight to height -- to explore whether those who were overweight or obese at age 14 or 31 had a different early stroke risk compared to those who were not overweight or obese at those ages.

About 1 in 20 participants had a clot-caused stroke, also called a transient ischemic attack, or mini-stroke, during the average follow-up period of almost 39 years after the age 14 evaluation and nearly 23 years after the age 31 assessment. The current study's analysis ended in 2020.

Women with obesity at age 14 were 87% more likely to have an early clot-caused stroke or mini-stroke, while those with obesity at age 31 were 167% more likely to have a stroke compared to those at appropriate weight.

"The increased risk for women who are overweight or obese may be attributed to several factors, such as hormonal and cardiovascular differences," Mikkola said.

However, outcomes between women and men were different for hemorrhagic (bleeding) stroke. This type of stroke stems from bleeding into the brain by the rupture of a blood vessel.

Obese women at age 31 had almost 3 1/2 times increased risk of bleeding stroke, while obese men at the same age had more than 5 1/2 times heightened risk of bleeding stroke.

Researchers noted that weight is not the only health factor that affects stroke risk. Many others can decrease risk even among people who were overweight at a younger age, such as better eating, not smoking, getting healthy sleep, managing blood pressure, cholesterol and blood glucose levels, avoiding excess alcohol and being physically active.

It is unknown why the association of increased risk for clot-caused stroke did not apply to men. Researchers are studying potential causes and other risk factors in more depth.

"Studies in multiple populations find a relative increase in stroke in young adults in recent years," said Dr. Larry Goldstein, the author of an editorial accompanying the study and a member of the American Heart Association's Stroke Council. He was not involved in the study.

As the authors acknowledged, the study occurred in Finland, so the results may not apply to other populations.

It also was observational, so researchers can't conclude that excess weight or obesity in young adulthood directly caused later-life stroke, said Goldstein, chair of the department of neurology and co-director of the Kentucky Neuroscience Institute at the University of Kentucky in Lexington.

"We've seen incredible gains in the fight against stroke in recent years, but the risk of stroke in young individuals has been increasing," said Dr. Laurel Cherian, division chief of cerebrovascular diseases at Rush University System for Health in Chicago.

"This study may help focus attention on the importance of metabolic health in young women as an important area for further study," Cherian said.

The link between chronic inflammation and excess fatty tissue is another valid point that this study raises. Inflammation is associated with numerous diseases, said Dr. Alison Caruana, a stroke neurologist at Stony Brook Medicine in Stony Brook, N.Y.

However, it's important to address weight in young people with sensitivity. This would "avoid adopting excessive dieting or exercise habits, which can also have negative consequences on health in adulthood," Caruana said.

"As long as providers are trained to recognize these patterns and refer to specialists where necessary, we can establish lifelong healthy habits in both adolescent boys and girls," she said.

Dr. Muhammad "Mud" Alvi, medical director of stroke at the West Virginia University Rockefeller Neuroscience Institute in Morgantown, W. Va., added that "being healthy is a lifelong process." Decisions in young adulthood "have health consequences down the road."