Endocrine Abstracts

Background: South Asians are at higher risk of vascular disease than the indigenous UK population. Susceptibility to conventional cardiovascular risk factors does not entirely account for this discrepancy. Vitamin D deficiency within this group may be an important patho-physiological contributor and an overlooked treatable cardiovascular risk factor.

Aims: To determine whether serum 25-(OH) Vitamin D concentration independently associates with a surrogate of arterio-slcerotic aortic stiffness in UK South Asians and test the hypothesis that Vitamin D status is a determinant of vascular wall pathology.

Methods: A cross-sectional association study. South Asian (SA) and White European (WE) groups were recruited from a multiethnic cardiovascular risk screening programme (ADDITION study: NCT00318032). Volunteers consented to non-invasive vascular measurements (carotid-femoral Pulse Wave Velocity (cfPWV) and biochemistry (25-(OH)VitD, PTH)). CfPWV is a recognised gold standard of aortic stiffness and is prospectively linked to vascular outcomes.

Results: Two hundred and thirty-one (SA=110, WE=121) individuals underwent cfPWV and 25-(OH)VitD measurements. Groups were matched for age (SA: 55.5 (0.89) vs WE: 55.8 (0.87) years, P=0.97), gender (SA Male 61 versus WE Male 57%, P=0.41), mean arterial pressure (SA: 97.2 (0.9) versus WE: 99.7 (1.0) mmHg, P=0.08), fasting glucose (SA: 5.9 (0.1) versus WE: 5.7 (0.2) mmol/l, P=0.59), smoking (SA: 10 versus WE: 11%, P=0.87) and prescribed anti-hypertensives. Ten-year CVD risk scores were similar and correlated strongly with cfPWV in both groups (r=0.8, P<0.001).

CfPWV was higher (SA: 9.30 (0.16) versus WE: 8.63 (0.13) ms/l, P<0.01) and 25-(OH) Vitamin D lower in the SA group (SA: 20.31 (1.3) versus WE: 55.12 nmol/l, P<0.01). Univariate-factors independently relating to cfPWV were log25-(OH)VitD, age, mean arterial pressure, glucose, BMI, gender, height, SA ethnicity. In linear regression modelling log25-(OH)VitD inversely associated with cfPWV in SA after adjustment for significant co-factors (beta co-efficient −0.28 (−1.16–0.02, P<0.01).

Conclusion: Serum 25-(OH)VitD concentration inversely relates to measures of arterial wall pathology in South Asians, the strength of the association being similar to glucose PWV interactions.