The role of inheritance and environment in predisposition to vascular disease in people of African descent.
OBJECTIVE
This study sought to compare vascular reactivity and carotid intima media thickness (CIMT) between Afro-Caribbean people in the United Kingdom (UK) and the West Indies and Afro-Caribbean and Caucasian people in the UK.


BACKGROUND
Attenuated vascular reactivity and increased CIMT in black patients is seen as evidence for predisposition to vascular disease, but no comparisons exist between Afro-Caribbean people in different settings, which can provide insight into non-inherited determinants of increased ethnic susceptibility.


METHODS
A representative community sample of 81 healthy Afro-Caribbean people and 101 Caucasian people in the UK was compared with 197 matched Afro-Caribbean people in Jamaica. Small vessel reactivity 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, DeltaRI(ALB)) and glyceryl trinitrate (5 microg/min, DeltaRI(GTN)). The CIMT was measured ultrasonographically in the distal 1 cm of the common carotid artery.


RESULTS
Mean DeltaRI(ALB) was 4.2 percentage points (95% confidence interval [CI], 2.3 to 6.1, p < 0.001) lower in UK Afro-Caribbean people compared with Jamaican Afro-Caribbean people and 2.6 percentage points (95% CI, 0.4 to 4.7, p = 0.02) lower compared with Caucasian people, after adjusting for vascular risk profile. Adjusted mean CIMT of UK Afro-Caribbean people was 0.13 mm (95% CI, 0.08 to 0.17, p < 0.001) greater compared with Jamaican Afro-Caribbean people and 0.05 mm (95% CI, 0.01 to 0.10, p = 0.02) greater compared with Caucasian people.


CONCLUSIONS
Healthy UK Afro-Caribbean people have greater and Jamaican Afro-Caribbean people have less impairment of vascular reactivity and intima media thickness compared with UK Caucasian people, suggesting that potentially modifiable environmental interactions may contribute to excess vascular disease in Afro-Caribbean people.
Cardiovascular Division, King's College London School of Medicine, London, United Kingdom. lalit.kalra@kcl.ac.uk
Lalit
L
Kalra
Curtis
C
Rambaran
Elizabeth
E
Iveson
Philip J
PJ
Chowienczyk
Ian
I
Hambleton
James M
JM
Ritter
Ajay
A
Shah
Rainford
R
Wilks
Terrence
T
Forrester
D044383:Black People; D001808:Blood Vessels / Q000502:physiology; D002339:Carotid Arteries / Q000473:pathology; D015984:Causality; D004777:Environment; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012307:Risk Factors; D017539:Tunica Intima / Q000473:pathology; D017540:Tunica Media / Q000473:pathology; D006113:United Kingdom; D014652:Vascular Diseases / Q000453:epidemiology / Q000209:etiology* / Q000235:genetics*; D014900:West Indies; D044465:White People