Objectives: Stroke is elevated in people of black African descent, but evidence for excess subclinical cerebrovascular disease is conflicting, and the role of risk factors in determining any ethnic differences observed unexplored.
Methods: We compared prevalence of brain infarcts, and severe white matter hyperintensities (WMHs) on cerebral MRI, in a community-based sample of men and women aged 58–86 of African Caribbean (214) and European (605) descent, in London, UK. Resting, central and ambulatory blood pressure (BP) were measured; diabetes was assessed by blood testing and questionnaire.
Results: Mean age was 70. Multiple (≥4) brain infarcts and severe WMH occurred more frequently in African Caribbeans (18/43%), than Europeans (7/33%, P = 0.05/0.008). Separately, clinic and night-time ambulatory BP were significantly associated with severe WMH in both ethnic groups; when both were entered into the model, the association for clinic SBP was attenuated and lost statistical significance [1.00 (0.98–1.02) P = 0.9 in Europeans, 1.00 (0.97–1.04) P = 0.9 in African Caribbeans], whereas the association for night-time SBP was retained [1.04 (1.02–1.07) P <0.001 in Europeans, 1.08 (1.03–1.12), P = 0.001 in African Caribbeans]. The greater age-adjusted and sex-adjusted risk of severe WMH in African Caribbeans compared with Europeans [2.08 (1.15–3.76) P = 0.02], was attenuated to 1.45 [(0.74–2.83) P = 0.3] on adjustment for clinic and night-time systolic pressure, antihypertensive medication use and glycated haemoglobin.
Conclusion: African Caribbeans have a greater burden of subclinical cerebrovascular disease than Europeans. This excess is related to elevated clinic and ambulatory BP, and to hyperglycaemia.
aDepartment of Radiology, University of Washington Medical Centre, Seattle, Washington, USA
bNational Heart & Lung Institute, Imperial College London
cDepartment of Radiology, St Mary's Hospital, Imperial College NHS Healthcare Trust, London, UK
Correspondence to Nish Chaturvedi, National Heart & Lung Institute, Imperial College London, 59-61 North Wharf Road, London W2 1PG, UK. Tel: +44 207 594 3381; fax: +44 207 594 3392; e-mail: firstname.lastname@example.org
Abbreviations: ABPM, ambulatory blood pressure monitoring; ACR, albumin/creatinine ratio; ARIC, Atherosclerosis Risk in Communities; BPb, lood pressure; CHS, Cardiovascular Health Study; CHD, coronary heart disease; CVD, cardiovascular disease; HOMA-IR, Homeostasis model assessment of insulin resistance; NOMAS, North Manhattan Study; PWV, pulse wave velocity; SABRE, Southall And Brent REvisited; WMH, white matter hyperintensity
Received 13 November, 2012
Revised 24 June, 2013
Accepted 9 July, 2013
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