Black and Asian people living with major cardiometabolic risk factors do not generally face a higher hazard of stroke than White patients with the same conditions, according to a population-based longitudinal study drawing on electronic health records from South London. The finding, published in BMC Public Health, indicates that a history of hypertension, diabetes and socioeconomic status partially explains ethnic inequality in stroke risk, rather than ethnicity amplifying the danger once those conditions are present. Researchers Marc Delord and Abdel Douiri analysed records from 41 general practices covering an urban, multiethnic, relatively young and socioeconomically deprived population.
Their cohort included 651,888 of the 849,968 registered patients, or 76.7 percent, of whom 8.6 percent were Asian, 18.2 percent Black and 73.2 percent White, with 54.1 percent female. The study period spanned registrations between 2005 and 2021. The burden of stroke was unevenly distributed across ethnic groups.
Among Black patients, 2.1 percent had a recorded stroke during the observation window, compared with 1.2 percent of Asian patients and 1.0 percent of White patients. The team set out to estimate the impact of ethnicity on the hazard of stroke among people already carrying hypertension, diabetes or hypercholesterolaemia. Methodologically, the study went beyond standard survival analysis.
The researchers built multistate models that treated disease progression as a sequence of transitions: transition 1 captured the move into hypertension, diabetes or hypercholesterolaemia, while transition 2 captured the move from one of those cardiometabolic risk factors to stroke. The models incorporated the date of stroke onset, recorded risk factors and the Index of Multiple Deprivation, allowing ethnicity effects to be estimated separately for each stage of the pathway. The results split cleanly along that two-stage structure.
Asian and Black patients generally showed a higher risk of transitioning into hypertension, diabetes or hypercholesterolaemia than White patients, indicating that the earlier stage of the pathway is where ethnic disadvantage concentrates. This pattern is consistent with the idea that a history of hypertension, diabetes and socioeconomic status partially explains ethnic inequality in stroke risk. At the second transition, the picture changed.
Ethnicity did not affect the move from cardiometabolic risk factors to stroke, with one exception: among patients with hypercholesterolaemia, Black patients had a higher risk of stroke than White patients. The authors conclude that Black ethnicity does not confer excess hazard of stroke in patients with hypertension or diabetes, an observation they extend to Asian patients as well. The excess hazard associated with Black ethnicity appeared only within the hypercholesterolaemia subgroup, a narrower and more specific signal than a blanket elevation of stroke risk across all cardiometabolic conditions.
Because the cohort was drawn from a youthful, deprived, urban population in a single London region, the findings are most directly relevant to similar settings, and the analysis relied on routinely recorded electronic health data rather than adjudicated clinical assessments. As an observational study using general practice records, the work establishes associations along a disease pathway rather than proving causal mechanisms.
Even so, the two-stage modelling offers a template for disentangling where in the progression from health to cardiometabolic disease to stroke ethnic differences actually arise, and the answer, on this large South London dataset, is chiefly at the first step.
Subject of Research: Ethnic differences in the transition from cardiometabolic risk factors to stroke in a South London population cohort
Article Title: Does ethnicity alter the hazard of stroke in patients with major modifiable cardiometabolic risk factors? A population-based longitudinal study using electronic health records in South London
Article References: Delord, M., & Douiri, A. (2026). Does ethnicity alter the hazard of stroke in patients with major modifiable cardiometabolic risk factors? A population-based longitudinal study using electronic health records in South London. BMC Public Health. https://doi.org/10.1186/s12889-026-29557-6
Image Credits: AI Generated
DOI: 10.1186/s12889-026-29557-6
Keywords: stroke, ethnicity, hypertension, diabetes, hypercholesterolaemia, multistate models, electronic health records, South London, health inequalities, cardiometabolic risk factors, primary care, BMC Public Health
News Source: Cassandra Pierce. (October 28, 2026). Ethnicity Does Not Raise Stroke Risk Once Hypertension or Diabetes Sets In, South London Records Show. Scienmag.
