Low Birthweight Raises Stroke Risk in Young Adults, Swedish Study Finds

A large population-based study from Sweden has found that people born with low birthweight face a significantly higher risk of stroke in young adulthood — and that this risk holds regardless of their body mass index or gestational age at birth.

The findings were presented at the European Congress on Obesity (ECO2026) in Istanbul, Turkey, drawing attention to how early-life factors can shape cardiovascular health decades later.

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Researchers from the University of Gothenburg, including Dr Lina Lilja and Dr Maria Bygdell, analysed data from nearly 800,000 Swedish men and women born between 1973 and 1982.

The team cross-referenced records from four national registers — the Medical Birth Register, National Conscription Register, National Patient Register, and the Cause of Death Register — to track stroke incidence up to December 31, 2022.

The study recorded 2,252 first stroke events among participants, comprising 1,624 ischaemic strokes and 588 intracerebral haemorrhages.

Individuals born with birthweights below the median of 3.5 kg showed a 21 percent higher overall risk of stroke, with similarly elevated risks seen across both stroke types. Breaking it down by sex, men with low birthweight faced a 23 percent increased risk, while women faced an 18 percent increase.

Crucially, these associations remained consistent even after accounting for gestational age and BMI in young adulthood — neither of which emerged as significant predictors of stroke on their own.

While stroke rates have declined overall in high-income countries in recent decades, the trend has been less encouraging among younger and middle-aged populations.

In several regions — including parts of Southeast Asia, Oceania, and high-income nations such as Sweden, the United States, and the United Kingdom — stroke incidence is actually rising among younger adults, making the study's findings particularly timely.

The authors concluded that lower birthweight is associated with a higher risk of early adult stroke in both men and women, and across both major stroke types.

They suggested that low birthweight should be factored into stroke risk assessments for adults, potentially informing preventive strategies for future generations.