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Research led by the University of Gothenburg in Sweden suggests that low birthweight is a risk factor for having a stroke in younger adulthood.
In a study including just under 800,000 people, the investigators found that risk for early stroke events was 18-23% higher in men and women who had a birth weight under the median level than those with a higher birth weight.
Around 795,000 people in the U.S. have a stroke each year. Although it can affect people of any age, it is much more common in older individuals with estimates of prevalence suggesting that 0.9% of 18–44 year olds have strokes versus 3.8% of those in the 45–64 year age group and 7.7% of people aged 65 and over.
Low birth weight has been previously linked to an increased risk for stroke in several studies. Researchers think that low birth weight is an indicator of exposure to an adverse environment in the womb that may adversely affect the cardiovascular system of the fetus in a way that increases stroke risk—for example, by increasing the risk of high blood pressure.
Over the last 10-15 years, stroke prevalence has stayed the same in older adults but has gone up by 14-16% in 18-64 year-olds. Lina Lilja, a doctoral student at the University of Gothenburg, and colleagues aimed to investigate whether low birth weight increased the risk of stroke in younger adults.
They included 420,173 men and 348,758 women from Sweden who were born between 1973 and 1982 and followed up from birth until 2022. The researchers collected data on birth weight, gestational age, and body mass index in young adulthood, as well as information on first stroke and the type of stroke.
Overall, 2252 first stroke events were recorded at an average age of 36 years. Of these, 1624 were ischemic stroke (average age 37 years) and 588 were intracerebral hemorrhage (average age 33 years).
The results, which will be presented at the European Congress on Obesity in Istanbul later this year, showed that birth weight below the median (3.5kg) increased the risk for all stroke by 21%. The rates of stroke were slightly higher in men with a low birthweight at 23% versus women with a low birthweight at 18%.
Notably, gestational age at birth and young adult body mass index were not linked to stroke risk in this study.