A forthcoming presentation at the European Congress on Obesity (ECO2026) in Istanbul, Turkey, scheduled for May 12-15, will highlight novel research indicating a heightened predisposition to stroke in early adulthood among individuals with a lower birth weight. This elevated risk factor persists irrespective of their body mass index (BMI) during young adulthood or their gestational age at birth. The comprehensive Swedish study, encompassing nearly 800,000 participants, posits that birth weight could be integrated into the stratigification of stroke risk for adults, as suggested by the study’s principal investigators, Dr Lina Lilja and Dr Maria Bygdell from the University of Gothenburg, alongside their collaborators.
While the overall prevalence of stroke has diminished in affluent nations over recent decades, this downward trend has been less pronounced in younger and middle-aged demographics compared to their elder counterparts. In certain geographical locales and within these younger age cohorts, stroke incidence is in fact escalating. This includes less prosperous regions of Southeast Asia and Oceania, as well as developed countries such as Sweden, the United States, and the United Kingdom (refer to editorial notes for illustrative examples).
Consequently, the research team embarked on an examination to ascertain whether factors such as birth weight, gestational age at birth, and an individual’s BMI as a young adult could serve as predictive markers for cerebrovascular events in younger populations. Although these developmental milestones are irrevocably established for contemporary young adults, they represent potential intervention points for future generations not yet conceived. The researchers scrutinized both prevalent stroke subtypes: ischemic strokes, stemming from a vascular obstruction within the brain (constituting over 75% of strokes, contingent on geographical distribution), and intracerebral hemorrhage (ICH), commonly referred to as a ‘brain bleed’ (accounting for up to 25% of all strokes).
This epidemiological investigation drew upon a cohort of 420,173 males and 348,758 females born in Sweden between 1973 and 1982. These individuals, aged 43 to 53 years presently if still living, represent all recorded live births from those years. Data pertaining to birth weight, gestational age, and young adult BMI were meticulously extracted from the Swedish Medical Birth Register and the National Conscription Register, respectively. The study participants were monitored until December 31, 2022.
Information regarding stroke events occurring in early adulthood was procured from Sweden’s National Patient Register and Cause of Death Register. This data encompassed 2,252 initial stroke events, with an average age of onset at 36 years; 1,624 ischemic stroke (IS) events, with an average age of 37 years; and 588 intracerebral hemorrhage stroke (ICH) events, with an average age of 33 years. Forty of these initial stroke events were not explicitly categorized. Given the mandatory nature of diagnosis registration within these national repositories, they furnish comprehensive nationwide data on individuals hospitalized or deceased due to stroke. The comparatively modest number of recorded events underscores the lower absolute stroke risk within these younger adult demographics. All analytical procedures incorporated adjustments for gender, year of birth, gestational age, parental country of origin, and age at the time of adult BMI assessment.
The investigative team identified a 21% amplified risk of all stroke events collectively, as well as for ischemic stroke in isolation, and a 27% augmented risk of intracerebral hemorrhage strokes individually, among participants (both male and female) who exhibited a birth weight below the median (3.5 kg) when contrasted with those whose birth weight surpassed the median. Specifically, women with a birth weight below the median (3.5 kg) faced an 18% increased risk for all stroke types combined, while men encountered a 23% elevated risk, relative to individuals with birth weights above the median.
These observed correlations remained demonstrably independent of gestational age (the duration of fetal development in utero) and their BMI during young adulthood. Furthermore, gestational age itself showed no discernible association with stroke risk. The overall findings consistently mirrored each other across both genders.
The authors’ concluding remarks state: “Our research substantiates a link between diminished birth weight and an elevated probability of experiencing a stroke in early adulthood. This heightened risk is evident in both men and women, and applies to the primary stroke classifications, namely ischemic and hemorrhagic. Crucially, these associations were unaffected by gestational age at birth or BMI in young adulthood. These revelations suggest that birth weight could potentially be incorporated into the risk assessment protocols for adults susceptible to stroke.”
