Investigating the Relationship the Severity of Coronary Artery Disease with Serum Levels of Vitamin D in Men after Eliminating the Effect of Diet

Background: Coronary artery disease (CAD) is one of the most common cardiovascular diseases that can lead to mortality, inability, and lower productivity levels. Objective: The aim of this study was to determine the relationship between serum vitamin D level and cardiovascular risk factors and the severity of CAD after determining and eliminating the confounding effects of dietary patterns in male patients undergoing angiography. Methods: This descriptive-analytic study was carried out on 132 men undergoing angiography during 2017 and 2018. To this end, food frequency questionnaire (FFQ) and physical activity questionnaire (PAQ) were completed for the patients. Fasting blood sugar (FBS), triglyceride, total cholesterol, HDL-C, LDL-C and vitamin D levels were also investigated. Results: Serum vitamin D levels significantly decreased with an increase in CAD severity (p=0.001). Also, low serum levels led to the highest severity of CAD (p=0.005). However, there was no significant difference between patients with vitamin D deficiency with different degrees of CAD (p=0.084). Also, the highest percentage of individuals with normal serum levels of vitamin D was observed in the group without any blocked blood arteries (normal) (p=0.023). Conclusion: This study shows an inverse relationship between serum 25(OH) D level and the severity of CAD. Our data show that vitamin D plays an important role in preventing CAD. These findings could help design prospective studies and clinical trials on a wider scale to investigate the effects of vitamin D interventions in preventing the development of CAD.