To evaluate the association between birth weight and the risk of adult stroke in men, independent of body mass index (BMI) at young adult age.
We included 35,659 men born 1945-61 from the BMI Epidemiology Study with data on birth weight together with BMI in childhood (8 years) and young adulthood (20 years). Information on stroke events (1,184 first stroke events; 905 ischemic stroke [IS] and 234 intracerebral hemorrhage [ICH]) were retrieved from national registers in Sweden.
Birth weight was inversely associated with the risk of stroke (IS and ICH together; hazard ratio [HR] 0.88 per SD increase, 95% confidence interval [CI] 0.84;0.93), IS and ICH in a linear manner, independently of young adult BMI. This association was maintained when the analysis was restricted to individuals within the normal birth weight range only. Moreover, individuals with a birth weight in the lowest tertile followed by overweight at 20 years had an 81% increased risk of stroke (HR 1.81, 95%CI 1.29;2.54), compared with a reference group of individuals with birth weight in the middle tertile who were normal weight at 20 years.
We demonstrate an inverse association between birth weight and risk of adult stroke, IS, and ICH, independent of young adult BMI. These findings suggest that low birth weight should be included in assessments of stroke risk in adult age.

Copyright © 2021 The Author(s). Published by Elsevier Inc. All rights reserved.