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,

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 excessive weight at age 14 were associated with later clot-caused stroke risk despite having lost weight by age 31. Also, women with excessive weight 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, BM, 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 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:

• Women affected by 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. Similar associations were not found among men.
• Women with obesity at age 31 had almost 3.5 times increased risk of bleeding stroke, and men with obesity at age 31 had more than 5.5 times increased risk of bleeding stroke.
• BMI measurements earlier in childhood or later in adulthood did not appear to affect the results.