The purpose of this study was to examine the association of demographic factors, serum Vitamin D levels, hypertension (HTN) (by HTN diagnosis, systolic blood pressure [SBP] and diastolic blood pressure [DBP]), serum (hs-CRP) and endothelial measures of inflammation upon the prevalence of depression in adults with coronary artery disease (CAD) from central North Carolina. A literature derived theory, the Puglisi Model of Vitamin D Levels' Associations with Depression, guided this study. Vitamin D levels, measures of blood pressure, and serum and endothelial measures of inflammation, were theorized as being associated with depression.
A cross-sectional, associational design was employed in the parent study from which previously frozen alliquoted blood of subjects with CAD was further analyzed to assess the serum Vitamin D levels and liver function. This convenience sample of 101 persons with CAD who presented between 2007 and 2010 at the University of North Carolina Hospital's Cardiac Catheterization lab was utilized. The majority of the sample of well-controlled persons with CAD was male (66%), White (81%), had hypertension (81%), and low serum Vitamin D levels (82%). Depression, found as a diagnosis in 27%, was not significantly associated with Vitamin D levels (p = 0.17), even when controlling for demographic factors (AOR 0.96; p = 0.13; 95% CI [.90 - 1.01]). There were no differences between brachial artery flow mediated dilation (BAFMD), augmentation index, and high sensitivity C-reactive protein (hs-CRP) by depression group, but there was for reactive hyperemia index (RHI) [t = 1.97; df = 99; p = 0.05]. Vitamin D levels were inversely associated with both SBP (p < 0.001) and DBP (p < 0.001), but Vitamin D levels were not associated with a diagnosis of HTN (AOR 0.97; p = 0.28; 95% CI [.92, 1.02]. Controlling for the potential confounders of age, sex, race, body mass index, liver and kidney functions did not alter the significant association between Vitamin D levels and SBP and DBP (p = 0.05). Vitamin D levels were significantly associated with two inflammatory measures—hs-CRP and augmentation index, but not with BAFMD and RHI. When controlling for age, sex, race, BMI and Vitamin D levels, only hs-CRP but none of the three endothelial measures of inflammation (RHI, BAFMD nor augmentation index [AI]), were associated with depression (AOR 0.956; p = 0.13; 95% CI [.90, 1.01]).
Nurses should be aware that most of the adults with CAD herein had low or insufficient Vitamin D levels, and that Vitamin D levels may significantly affect SBP and DBP in persons with CAD and perhaps other populations as well. Many persons have depression around the time of their cardiac event or thereafter. Because increased morbidity and mortality occur in individuals with decreased Vitamin D levels, and depression, even when identified and treated in persons with CAD is associated with worsened outcomes, appropriate screening for and treatment of low serum Vitamin D levels is needed. Thus, advanced practice clinicians caring for persons with CAD should encourage screening of Vitamin D levels, and treatment of low levels with appropriate supplementation.
Further studies are needed to explore why some endothelial measures are associated with Vitamin D levels and depression, and others are not. Additional studies should seek to confirm the inverse association of Vitamin D levels with SBP and DBP while accounting for season of the year and other potential confounders. Finally, studies should utilize a depression screening tool to test the Puglisi model's proposed association between low Vitamin D levels with an increased occurrence of depression in both persons with CAD and other populations.
|Advisor:||Crane, Patricia B.|
|Commitee:||Lee, Craig R., Letvak, Susan, Van Horn, Elizabeth, Wideman, Laurie|
|School:||The University of North Carolina at Greensboro|
|School Location:||United States -- North Carolina|
|Source:||DAI-B 75/10(E), Dissertation Abstracts International|
|Subjects:||Mental health, Medicine, Nursing, Nutrition|
|Keywords:||Coronary artery disease, Depression, Endothelial dysfunction, Hypertension, Inflammation, Vitamin d|
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