The relationship between low birth weight and neurological disorders: a prospective cohort study in the UK Biobank

Birth weight as a marker of fetal growth has been linked to later health outcomes, but its relationship with adult neurological disorders is less well characterised, and few large studies have evaluated multiple neurological disorders within a unified analytical framework. We analyzed 279,842 UK Biobank participants with self-reported birth weight. Birth weight was modeled continuously (per 1-kg increment) and categorically (low < 2.5 kg, reference 2.5–4.0 kg, high ≥ 4.0 kg). Incident multiple sclerosis (MS), Alzheimer’s disease (AD), Parkinson’s disease (PD), epilepsy, migraine and cerebrovascular disease (CVD) were ascertained from hospital and registry records (ICD-10). Logistic regression estimated OR and 95% CI, adjusting for age, sex, education, race, and socioeconomic status, with stratification by sex and age. Low birth weight was associated with higher risk of AD (OR = 1.31, 95% CI 1.14–1.51), epilepsy (OR = 1.37, 95% CI 1.24–1.51), and CVD (OR = 1.32, 95% CI 1.25–1.40). AD showed a U-shaped pattern, with high birth weight increasing risk (OR = 1.19, 95% CI 1.04–1.36). Each 1-kg increase in birth weight corresponded to 12% lower odds of epilepsy (OR = 0.88, 95% CI 0.84–0.93) and 11% lower odds of CVD (OR = 0.89, 95% CI 0.85–0.94). Findings were consistent across sex and age strata, and no associations were observed for MS, PD, or migraine after full adjustment. Low birth weight was independently associated with increased risk of AD, epilepsy, and CVD in adulthood, but not with MS, PD, or migraine, after adjustment for measured confounders. These observational findings, which remain susceptible to residual confounding and measurement error, support the Developmental Origins of Health and Disease framework and underscore the enduring influence of early-life growth on neurological health. Future research should incorporate objective birth records, encompass more diverse populations, and explore how birth weight can be integrated into life-course risk prediction models and prenatal preventive strategies.