Are vitamin D deficiency and VDR gene polymorphisms associated with high blood pressure as defined by the ACC/AHA 2017 criteria in postmenopausal women?

Abstract

Objectives: To assess the vitamin D levels, prevalence of vitamin D deficiency and genotypes of Fok-I, Bsm-I, Apa-I and Taq-I polymorphisms in the VDR gene and to determine whether vitamin D deficiency and VDR gene variants are associated with blood pressure levels and systemic arterial hypertension as defined by the 2017 ACC/AHA criteria.

Study design: A cross-sectional study of biobanked blood samples from 339 postmenopausal women.

Main outcome measures: Blood pressure strata were defined according to the 2017 ACC/AHA cutoffs. Circulating 25(OH)D levels were considered deficient if <20 ng/mL.

Results: Mean serum total 25(OH)D levels were 22.99 ± 8.54 ng/mL, and 40.1% of participants were deficient in vitamin D. Overall, 7.7% had elevated blood pressure, 36.6% had stage 1 and 37.8% had stage 2 hypertension. Mean total (p = 0.014) and free 25(OH)D levels (p = 0.029) were lower in women with stage 2 hypertension than in those with normal blood pressure. A higher prevalence rate of stage 2 hypertension was associated with age (PR 1.058; 95%CI 1.033-1.083; p < 0.001), BMI (PR 1.046; 95%CI 1.025-1.068; p < 0.001), vitamin D deficiency (PR 1.333; 95%CI 1.016-1.749; p = 0.038) and Taq-I polymorphism (PR 1.764; 95%CI 1.030-3.019; p = 0.039). Women with vitamin D deficiency and the AA+AG genotype of Taq-I polymorphism were 33% and 76% more likely to have stage 2 hypertension, respectively, but these associations lost significance when adjusted for age and BMI.

Conclusion: The results suggest that vitamin D deficiency and Taq-I polymorphism are associated with stage 2 hypertension, depending on age and BMI, in postmenopausal women.

Keywords: Blood pressure; Polymorphisms; Postmenopausal women; VDR gene; Vitamin D deficiency.