In new research to be presented at this year’s European Conference on Obesity (ECO2026) in Istanbul, Turkey (May 12-15), researchers show an increased risk of stroke in young adulthood for children with low birth weight, regardless of body mass index (BMI) as young adults or gestational age at birth. The study of nearly 800,000 people in Sweden shows that low birth weight could be included in the assessment of stroke risk for adults, say the authors, who include Dr Lina Lilja and Dr Maria Bygdell from the University of Gothenburg, Gothenburg, Sweden, and colleagues.
While the incidence of stroke has overall declined in high-income countries in recent decades, this decline has been less pronounced in young and middle-aged adults compared to older adults. In some regions and in these younger age groups, the incidence of stroke is even increasing – including lower-income countries in south-east Asia and Oceania and high-income countries such as Sweden, the US and the UK (see examples in the notes to the editor).
So the authors decided to investigate whether certain factors such as birth weight, gestational age at birth and BMI as a young adult could be risk factors for stomach in younger adults. While of course for young adults today these life events have already passed, for children not yet conceived these are factors that could be targeted with interventions. The authors investigated both common forms of stroke – ischemic, caused by blockage of blood vessels in the brain (which account for more than three-quarters of strokes, depending on location). and intercerebral hemorrhage (ICH) or “bleeding brain” strokes (accounting for up to a quarter of all strokes).
This population-based study included 420,173 men and 348,758 women born between 1973 and 1982 in Sweden (and therefore aged 43 to 53 years if still alive today and representing all recorded live births from those years) with data on birth weight, gestational age and BMI at young age and the National Register of Writing. Study participants were followed until December 31, 2022.
Information on early adult stroke events was retrieved from the National Patient Registry and Cause of Death Registry in Sweden – 2252 first stroke events, mean age 36 years. 1624 ischemic stroke [IS] events, mean age 37 years. and 588 cerebral intracerebral hemorrhage [ICH] events, mean age 33 years (with 40 of these first unclassified strokes). Since the registration of diagnoses in these registries is mandatory, they provide nationally comprehensive data on people who have been hospitalized or died of stroke. The relatively low number of events reflects that these are younger adults in whom the absolute risk of stroke is lower. All analyzes were adjusted for sex, year of birth, gestational age, parents’ country of birth and age at adult BMI.
The authors found that there was a 21% increased risk of all stroke events combined, as well as ischemic stroke alone, and a 27% increased risk of cerebral intracerebral hemorrhage alone, for subjects (males and females combined) who had a birth weight below the median (3.5 kg) compared with subjects who had a birth weight above the median. Women with a birth weight below the median (3.5 kg) had an 18% increased risk for all strokes and men a 23% increased risk compared with those with a birth weight above the median.
The results were independent of gestational age (how long the child was in the womb before birth) and BMI as a young adult. Gestational age alone was not associated with stroke risk. Overall results in each case were similar for women and men.
The authors conclude: “We demonstrate that lower birth weight is associated with an increased risk of early adult stroke. There is a similar increased risk for both men and women for both major types of stroke, ischemic and hemorrhagic, and the results were independent of gestational age at birth and BMI as young adults. These findings suggest that low birth weight may be included in estimates of stroke risk in adults.”
