Abstract
Postmenopausal status has been associated with an unfavorable phenotype tied to hormonal and metabolic changes, which collectively could contribute to an increased risk of cardiovascular disease. Vitamin D deficiency is frequent in postmenopausal women and may be linked to this phenotype and especially to an increased risk of developing hypertension. Vitamin D actions are modulated by the vitamin D receptor (VDR), and metabolic abnormalities have been associated with VDR gene variants in different populations. The aims of the present study were 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 by the 2017 ACC/AHA definition in postmenopausal women. We conducted a cross-sectional study of biobanked blood samples from 339 postmenopausal women with no evidence of clinical disease. Blood pressure strata were defined according to the 2017 ACC/AHA cutoffs. Circulating 25(OH)D levels were considered deficient if <20 ng/mL. Genotype analysis was performed by RT-PCR with allelic discrimination assays. 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. The CC+CT genotypes of Bsm-I and the AA+AG genotypes of Taq-I polymorphisms were more frequent in women with stage 2 hypertension (Bsm-I CC+CT: 85.8% vs. TT: 14.2%, p=0.045; Taq-I AA+AG: 91.3% vs. GG: 8.7%, p=0.021). A higher prevalence ratio 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 analyses lost significance when adjusted for age and BMI. In conclusion, the present results suggest that vitamin D deficiency and Taq-I polymorphism are associated with stage 2 hypertension, depending on age and BMI, in postmenopausal women.
The effect of a combined oral calcium and vitamin D supplement for treating mild to moderate vitamin D deficiency in postmenopausal women
