Evaluation of vitamin D relationship with type 2 diabetes and systolic blood pressure

OBJECTIVE To investigate whether relationships exist among vitamin D, type 2 diabetes mellitus (T2DM), and blood pressure in Trinidadian subjects with T2DM. RESEARCH DESIGN AND METHODS This was a case-controlled study to determine if vitamin D levels were lower in patients with T2DM. After data analysis, an exploratory hypothesis of vitamin D relationship to systolic blood pressure (SBP) was developed. Plasma calcifediol (25(OH)D) concentrations were used as a measurement for vitamin D levels and were determined by ELISA. Cholesterol levels were measured by an automated dry chemistry analyzer and blood pressure was measured using an automatic blood pressure monitor. RESULTS There was no significant difference (p=0.139, n=76) in 25(OH)D levels between patients with T2DM and controls. Subjects with SBP above 130 mm Hg were 8 times more likely to have a 25(OH)D plasma concentration above 25 ng/mL (OR 7.9 (2.2 to 28.7)), and were 5 times (OR 4.7 (1.7 to 15.1)) more likely to have a 25(OH)D plasma concentration above 30 ng/mL (OR 7.5 (2.3-24.2)). Vitamin D levels moderately and positively correlated with SBP (rs=0.38, p=0.001). CONCLUSIONS There was no significant difference in the 25(OH)D levels between patients with T2DM and controls (p=0.139). Patients with SBP under 130 mm Hg were 8 times more likely to have a vitamin D level above 25 ng/mL (OR 7.9 (2.2 to 28.7)). Further investigations are required to examine the relationship between vitamin D and SBP.