When stroke arrives silently — without any prior diagnosis of the conditions that typically precede it — the consequences for prevention and early intervention are profound. Nearly one in eight strokes among Black African adults in South London occurred in people with no previously identified vascular risk factor, compared to roughly one in sixteen among White adults. That gap points not to biological inevitability but to a systemic failure in risk detection that three decades of data have failed to close.
Drawing on 8,515 participants in the South London Stroke Register between 1995 and 2024, this population-based cohort study stratified stroke risk factor prevalence and treatment rates by ethnicity, occupational class, and educational attainment. Black African adults experienced stroke at a median age of 59.0 years versus 74.1 years among White adults — a 15-year differential. Adjusted Poisson regression models revealed that Black Caribbean participants carried 2.23 times the prevalence of diabetes and 1.29 times the prevalence of hypertension compared to White counterparts; Black African participants showed 1.92 times the diabetes burden and 1.47 times the hypertension burden. Lower occupational and educational groups compounded these disparities additively. Strikingly, atrial fibrillation prevalence was lower in Black groups — a finding that likely reflects under-detection rather than true biological protection.
This 29-year longitudinal span makes the dataset unusually authoritative, lending weight to conclusions that shorter studies cannot sustain. The persistent gap in undiagnosed risk — despite decades of awareness campaigns — suggests structural barriers to screening access rather than patient behavior explaining the divergence. The atrial fibrillation finding deserves particular attention: AF is highly treatable when detected, and its apparent underrepresentation in minority and lower-SES groups likely signals diagnostic blind spots that leave high-risk individuals without anticoagulation. While the register captures a specific urban South London population, limiting geographic generalizability, the mechanistic implications resonate broadly: socioeconomic disadvantage and ethnicity operate as independent, additive stroke risk amplifiers, and neither explains away the other. The study represents a confirmatory and sobering benchmark rather than a paradigm shift — the inequalities are documented, durable, and demand targeted primary prevention infrastructure.