Baby boys who weighed 2-2.75kg at birth were found to be 60 per cent more likely to have a stroke than those weighing 3.25-3.75kg.
In girls, those in the lowest birth weight category had a 34 per cent increased risk of stroke.
The findings, presented at the European Stroke Conference inFrance last week, come from recent analysis of the Copenhagen School Health Records Centre.
This included 97,391 boys and 93,772 girls born between 1936 and 1976.
Birth weight was compared with data on stroke events recorded in the Danish Hospital and Cause of Death Registers.
Cox regression showed that the relative risk was highest in those with the lowest birth weight.
Previous analysis by the same team has shown that among boys, BMI at 13 years of age is an independent predictor of stroke.
Those with a BMI z-score of 0.75 or more had a 35 per cent increased risk of ischaemic stroke in adulthood.
These findings mean that although some risk for ischaemic stroke appear to be present from birth, prevention possibilities are also available, said the researchers from the Centre for Health and Society in Copenhagen.
However, they also admitted that the dataset used to come to this conclusion does not allow for premature or full-term birth to be accounted for.
Further analysis focusing on stroke only confirmed by CT or MRI scans could be helpful, the researchers said.
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