Homocysteine, migration and early vascular impairment in people of African descent.
OBJECTIVE
A gradient of increased vascular risk with migration exists across the African diaspora. We investigated the hypothesis that differences in homocysteine/folic acid status contribute to this increased risk.


METHODS
Community cohort study of 73 Afro-Caribbeans in the United Kingdom and 151 matched Afro-Caribbeans in Jamaica with no conventional vascular risk factors.


METHODS
Subjects were compared for baseline characteristics, vascular risk profile, homocysteine (tHcy), folate and B(12) concentrations. Endothelium-dependent vasodilatation was assessed by measuring the absolute change from baseline in the reflection index (RI) of the digital volume pulse during intravenous infusion of albuterol (5 microg/min, Delta RI(ALB)) and glyceryltrinitrate (GTN) (5 microg/min, Delta RI(GTN)). Carotid intima media thickness (CIMT) was measured ultrasonographically in the distal 1 cm of the common carotid artery.


RESULTS
UK Afro-Caribbeans had higher tHcy (mean difference 2.3 (95% confidence interval 1.3 to 3.4) micromol/l) and lower folate (mean difference 3.2 (95% CI 1.8 to 4.7) microg/l) levels. Delta RI(ALB) was 5.1 (95% CI 2.5 to 7.6) percentage points lower and CIMT 0.124 (95% CI 0.075 to 0.173) mm greater in UK Afro-Caribbeans. Higher tHcy and lower folate concentrations correlated with impaired Delta RI(ALB) and increased CIMT. A 1 microg/l increase in folate concentration was associated with 0.3 (95% CI 0.1 to 0.5) percentage point increase in Delta RI(ALB) and 0.002 (95% CI 0.001 to 0.006) mm decrease in CIMT, independent of blood pressure, smoking and vascular risk profile.


CONCLUSIONS
Lower folate concentrations in UK compared with West Indian African-Caribbeans may contribute to the higher stroke risk seen in UK African-Caribbean people.
Kalra
L
L
Cardiovascular Division, King's College London School of Medicine, London, UK. lalit.kalra@kcl.ac.uk
Iveson
E
E
Rambaran
C
C
Sherwood
R
R
Chowienczyk
P
P
Ritter
J
J
Shah
A
A
Forrester
T
T
D000328:Adult; D015415:Biomarkers / Q000097:blood; D044383:Black People; D003430:Cross-Sectional Studies; D004641:Emigration and Immigration; D005260:Female; D005492:Folic Acid / Q000097:blood; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D007563:Jamaica / Q000208:ethnology; D008297:Male; D008875:Middle Aged; D010991:Plethysmography; D012307:Risk Factors; D018709:Statistics, Nonparametric; D006113:United Kingdom; D014652:Vascular Diseases / Q000208:ethnology* / Q000378:metabolism / Q000503:physiopathology
D015415:Biomarkers; D006710:Homocysteine; D005492:Folic Acid