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VITAMIN D STATUS IS ASSOCIATED WITH ARTERIAL STIFFNESS AND VASCULAR DYSFUNCTION IN HEALTHY HUMANS
E2049 JACC April 5, 2011 Volume 57, Issue 14
YOUNG INVESTIGATORS AWARDS VITAMIN D STATUS IS ASSOCIATED WITH ARTERIAL STIFFNESS AND VASCULAR DYSFUNCTION IN HEALTHY HUMANS ACC Special Session Ernest N. Morial Convention Center, Room 215 Sunday, April 03, 2011, 2:00 p.m.-2:15 p.m.
Session Title: Young Investigators Award Competition: Physiology, Pharmacology and Pathology Abstract Category: Physiology, Pharmacology, Pathology Presentation Number: 0410-05 Authors: Ibhar Al Mheid, Riyaz Patel, Johnathan Murrow, Alanna Morris, Konstantinos Aznaouridis, Ayaz Rahman, Lucy Fike, Nino Kavtaradze, Yusuf Ahmed, Irina Uphoff, Craig Hooper, Vin Tangpricha, R Wayne Alexander, Kenneth Brigham, Arshed Quyyumi, Emory University School of Medicine, Atlanta, GA Background: Mechanisms underlying vitamin D deficiency-mediated increased risk of cardiovascular disease and overall mortality remain unknown. Vitamin D influences endothelial and smooth muscle cell function, mediates inflammation and modulates the renin-angiotensin axis. We investigated the relationship between vitamin D status and vascular function in humans, with the hypothesis that vitamin D insufficiency will be associated with increased arterial stiffness and abnormal vascular function. Methods: We measured serum 25-hydroxyvitamin D in 554 participants (age, 47±13 years; 55% women) enrolled in the Emory Predictive Health study. Endothelial function was assessed as brachial artery flow-mediated dilation and microvascular function as digital reactive hyperemia index. Radial tonometry-derived central augmentation index and subendocardial viability ratio were measured to assess arterial stiffness and elasticity. Results: Mean 25-hydroxyvitamin D was 31.8±14 ng/ml, 47% of subjects had insufficient levels (<30 ng/ml). After adjustment for Framingham risk score, body mass index, race and medication use, serum 25-hydroxyvitamin D was a significant independent determinant of flow-mediated vasodilation (adjusted R2= 0.12, p= 0.008), reactive hyperemia index (adjusted R2= 0.2, p< 0.001), AIX (adjusted R2=0.16, p=0.001) and subendocardial viability ratio (adjusted R2= 0.17, p= 0.02). In 41 subjects with vitamin D insufficiency, normalization of vitamin D status at 6 months was associated with an increase in reactive hyperemia index (0.4±0.9, p=0.03) and subendocardial viability ratio (7.02±20, p=0.04), and a decrease in mean arterial pressure (4.8±8.4 mmHg, p=0.04). Conclusion: Vitamin D insufficiency is associated with increased arterial stiffness and endothelial dysfunction in the conductance and resistance blood vessels in humans, irrespective of traditional risk factor burden. Normalization of vitamin D status in insufficient individuals improves vascular function and is associated with a decrease in mean arterial pressure. Our findings provide impetus for larger trials to assess the effect of vitamin D therapy on prevention of cardiovascular disease.
YOUNG INVESTIGATORS AWARDS VITAMIN D STATUS IS ASSOCIATED WITH ARTERIAL STIFFNESS AND VASCULAR DYSFUNCTION IN HEALTHY HUMANS ACC Special Session Ernest N. Morial Convention Center, Room 215 Sunday, April 03, 2011, 2:00 p.m.-2:15 p.m.
Session Title: Young Investigators Award Competition: Physiology, Pharmacology and Pathology Abstract Category: Physiology, Pharmacology, Pathology Presentation Number: 0410-05 Authors: Ibhar Al Mheid, Riyaz Patel, Johnathan Murrow, Alanna Morris, Konstantinos Aznaouridis, Ayaz Rahman, Lucy Fike, Nino Kavtaradze, Yusuf Ahmed, Irina Uphoff, Craig Hooper, Vin Tangpricha, R Wayne Alexander, Kenneth Brigham, Arshed Quyyumi, Emory University School of Medicine, Atlanta, GA Background: Mechanisms underlying vitamin D deficiency-mediated increased risk of cardiovascular disease and overall mortality remain unknown. Vitamin D influences endothelial and smooth muscle cell function, mediates inflammation and modulates the renin-angiotensin axis. We investigated the relationship between vitamin D status and vascular function in humans, with the hypothesis that vitamin D insufficiency will be associated with increased arterial stiffness and abnormal vascular function. Methods: We measured serum 25-hydroxyvitamin D in 554 participants (age, 47±13 years; 55% women) enrolled in the Emory Predictive Health study. Endothelial function was assessed as brachial artery flow-mediated dilation and microvascular function as digital reactive hyperemia index. Radial tonometry-derived central augmentation index and subendocardial viability ratio were measured to assess arterial stiffness and elasticity. Results: Mean 25-hydroxyvitamin D was 31.8±14 ng/ml, 47% of subjects had insufficient levels (<30 ng/ml). After adjustment for Framingham risk score, body mass index, race and medication use, serum 25-hydroxyvitamin D was a significant independent determinant of flow-mediated vasodilation (adjusted R2= 0.12, p= 0.008), reactive hyperemia index (adjusted R2= 0.2, p< 0.001), AIX (adjusted R2=0.16, p=0.001) and subendocardial viability ratio (adjusted R2= 0.17, p= 0.02). In 41 subjects with vitamin D insufficiency, normalization of vitamin D status at 6 months was associated with an increase in reactive hyperemia index (0.4±0.9, p=0.03) and subendocardial viability ratio (7.02±20, p=0.04), and a decrease in mean arterial pressure (4.8±8.4 mmHg, p=0.04). Conclusion: Vitamin D insufficiency is associated with increased arterial stiffness and endothelial dysfunction in the conductance and resistance blood vessels in humans, irrespective of traditional risk factor burden. Normalization of vitamin D status in insufficient individuals improves vascular function and is associated with a decrease in mean arterial pressure. Our findings provide impetus for larger trials to assess the effect of vitamin D therapy on prevention of cardiovascular disease.