Low Birthweight Linked to Increased Stroke Risk in Young Adults

New research to be presented at the European Congress on Obesity (ECO2026) in Istanbul, Turkey, from May 12 to May 15, 2026, indicates that children born with low birthweight face an increased risk of stroke in young adulthood.

The findings demonstrate that this elevated risk exists independently of the individual’s gestational age at birth or their body mass index (BMI) as a young adult.

The study, which analyzed data from almost 800,000 people in Sweden, suggests that low birthweight should be integrated into stroke risk assessments for adults.

The research was led by Dr. Lina Lilja and Dr. Maria Bygdell of the University of Gothenburg in Gothenburg, Sweden, along with their colleagues.

Scientific Context and Previous Findings

The results presented at ECO2026 build upon existing research regarding the long-term health impacts of birth weight. A previous study published on June 27, 2021, also identified an inverse association between birth weight and the risk of adult stroke.

That earlier study focused on 35,659 men born between 1945 and 1961 from the BMI Epidemiology Study. Researchers tracked data on birth weight as well as BMI measured during childhood at age 8 and in young adulthood at age 20.

By retrieving data from national registers in Sweden, researchers identified 1,184 first stroke events. These included 905 ischemic stroke events and 234 intracerebral hemorrhage events.

The 2021 data showed that birth weight was inversely associated with the risk of ischemic stroke, intracerebral hemorrhage, and uncategorized strokes in a linear manner. This association remained consistent even when the analysis was restricted to individuals within the normal birth weight range.

The hazard ratio was calculated at 0.88 per standard deviation increase in birth weight, confirming that lower birth weights were linked to higher stroke risks, independent of BMI in young adulthood.

The Role of Subsequent Weight Gain

While the risk exists independently of BMI, certain weight trajectories appear to compound the danger. The earlier research highlighted a significant risk increase for those who experienced rapid weight gain after a low-birth-weight start.

Individuals who were in the lowest tertile for birth weight and subsequently became overweight by age 20 faced an 81% greater risk of stroke compared to a reference group. This reference group consisted of individuals in the middle birth weight tertile who maintained a normal weight at age 20.

This specific trajectory—low birth weight followed by young adult overweight—is considered a relevant risk marker globally. Experts note that this scenario may be particularly important for stroke risk in adults living in middle- and low-income countries.

Public Health Implications

The scale of the new Swedish study, involving nearly 800,000 participants, provides substantial evidence for the persistence of this risk across a large population.

Because the risk is independent of gestational age and young adult BMI, birthweight serves as a distinct early-life risk factor. This suggests that medical providers may need to consider birth history when evaluating a patient’s cardiovascular and cerebrovascular health.

By including low birthweight in adult stroke risk assessments, clinicians may be better equipped to identify high-risk individuals earlier in their lives, regardless of their current weight or BMI.