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 (r(s)=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.