Being overweight in youth may increase stroke risk in women before the age of 55

Women who are overweight during their teenage years or as young adults appear to have an increased risk of stroke before the age of 55, according to a new study from the University of Oulu, published in the high-ranking scientific journal Stroke. No similar risk was observed in men.

The study is based on health data collected over more than 50 years and indicates that women who were overweight at the ages of 14 or 31 had a higher risk of stroke before the age of 55. A stroke occurs when a blood vessel carrying blood to the brain becomes blocked. This is the most common type of stroke, accounting for nearly 90 per cent of all strokes.

The research showed that being overweight at the age of 14 increased the risk later in life, even if the person had lost weight by the age of 31. Similarly, being overweight at the age of 31 increased the risk, even if the person had been of normal weight at the age of 14. No similar stroke risk was observed in men.

“Our findings suggest that being overweight can have long-term health effects, even if the extra weight is temporary,” says doctoral researcher Ursula Mikkola from the Research Unit of Population Health at the University of Oulu. “Healthcare professionals should pay attention to overweight in young people and promote healthy eating habits and physical activity. Discussions about weight with young people, however, should be conducted without judgment and stigmatisation.”

The study examined participants from the 1966 Northern Finland Birth Cohort, which includes over 10,000 individuals whose health has been monitored since pregnancy. Researchers looked at body mass index (BMI) to determine whether being overweight or obese at the ages of 14 or 31 was associated with the risk of stroke before the age of 55. About one in twenty participants experienced a stroke, transient ischaemic attack (TIA), or brain haemorrhage during the study follow-up period.

A limitation of the study is that it is observational and therefore cannot establish a direct causal relationship between overweight and stroke. “Strokes at a young age are rare, so even a small number of cases can significantly impact risk assessments,” Mikkola points out. “Additionally, BMI only measures the ratio of height to weight, so a high BMI can be a misleading way to define obesity, particularly in muscular individuals who may have little fat despite their weight.”

The study showed that in all age groups, the risk of stroke was lowest in individuals with a normal BMI. “It is important to remember, however, that overweight is just one of many risk factors for stroke, and many other factors influence the risk more than previous overweight,” Mikkola notes. “Living healthily, by avoiding smoking and excessive alcohol consumption, keeping blood pressure, cholesterol, and blood sugar levels in check, and exercising adequately, keeps the risk of stroke low, even if one has previously been overweight,” she adds.

Research article: Mikkola U, Rissanen I, Kivelä M, Rusanen H, Kajantie E, Miettunen J, Paananen M. Overweight in Adolescence and Young Adulthood in Association With Adult Cerebrovascular Disease: The NFBC1966 Study. Stroke. 2024 Jun 6. doi: 10.1161/STROKEAHA.123.045444. Epub ahead of print. PMID: 38841866.

Last updated: 25.6.2024