[Vitamin D and hypertension]

SNP rs11185644 of RXRA gene is identified for dose-response variability to vitamin D3 supplementation: a randomized clinical trial

The level of serum 25-Hydroxyvitamin D [25(OH)D] has high heritability, suggesting that genes may contribute to variations in serum 25(OH)D level and vitamin D dose-response. As vitamin D deficiency has been linked to numerous diseases, understanding how genetic variation contributes to vitamin D dose-response is important for personalized vitamin D treatment and cost-effective disease prevention. To identify genetic variants responsible for vitamin D status and dose-response, we performed two vitamin D3 and calcium clinical supplementation trials in 2,207 postmenopausal Caucasian women. We examined the association of 291 SNPs with baseline serum 25(OH)D levels and 25(OH)D dose-response. Five SNPs, rs10500804 (P = 4.93 × 10⁻⁷), rs2060793 (P = 6.63 × 10⁻⁷), rs10741657 (P = 1.49 × 10⁻⁶), rs10766197 (P = 1.05 × 10⁻⁵) and rs11023380 (P = 7.67 × 10⁻⁵) in the CYP2R1 gene, as well as 6 SNPs, rs4588 (P = 7.86 × 10⁻⁷), rs2298850 (P = 1.94 × 10⁻⁶), rs1155563 (P = 6.39 × 10⁻⁶), rs705119 (P = 2.80 × 10⁻⁵), rs705120 (P = 1.08 × 10⁻⁴) and rs222040 (P = 1.59 × 10⁻⁴) in the GC gene were associated with baseline serum 25(OH)D levels. SNP rs11185644 near the RXRA was significantly associated with 25(OH)D dose-response (P = 1.01 × 10⁻⁴). Our data suggest that polymorphisms in the CYP2R1 and GC gene may contribute to variation in baseline serum 25(OH)D concentration, and that polymorphism rs11185644 may contribute to variation in 25(OH)D dose-response in healthy postmenopausal Caucasian women.

Inadequacies in the habitual nutrient intakes of patients with metabolic syndrome: a cross-sectional study

BACKGROUND

Dietary factors are important environmental factors associated with the prevalence of metabolic syndrome (MS). The objective of this study was to assess the habitual nutrient intakes of patients with MS.

METHODS

A cross-sectional study included 103 patients (82 % women) with MS seen at the endocrinology outpatient clinic of Hospital Universitario Onofre Lopes. Habitual nutrient intake data were collected at two 24-h dietary recalls. Macronutrient intake adequacies were classified according to the I Brazilian guidelines for the diagnosis and treatment of metabolic syndrome. The prevalence of inadequate micronutrient intake was estimated using the estimated average requirements (EAR) cut-point method after adjusting for intra- and interpersonal variances and energy.

RESULTS

The mean energy intake of the included patients was 1523.0 ± 592.2 kcal/d, higher in men (1884.0 vs. 1441.5 kcal/d in women; p = 0.003). The recommended percentage protein intake was exceeded in both women and men (18 % in women and 19 % in men). Although men consumed more fiber (18.8 vs. 13.3 g/d in women; p = 0.011), their intake was still inadequate. Women consumed more fat (47.6 vs. 41.3 g/d in men; p = 0.007). The prevalence of inadequate vitamin D and calcium intakes exceeded 80 % in both men and women and across all age groups. The same was observed for magnesium in men and women aged more than 30 years. The prevalence of inadequate vitamin E, riboflavin, and zinc intakes in men ranged from 50 to 75 %. The prevalence of inadequate vitamin A, vitamin C, thiamin, vitamin B6, copper, and selenium intakes in men and women was less than 50 %.

CONCLUSIONS

Patients with MS had high protein intake, low fiber intake, and high a prevalence of inadequate vitamin D, magnesium, and calcium intakes.

[Relation between parathyroid hormone and cardiovascular risk in patients with vitamin D deficiency]

BACKGROUND AND OBJECTIVES

Vitamin D deficiency and parathyroid hormone (PTH) are associated with an increased cardiovascular risk and arterial stiffness. The aim of our study is to compare the cardiovascular risk in subjects with low vitamin D, attending to the PTH concentration, as well as evaluating the response after administration of vitamin D.

PATIENTS AND METHODS

Prospective study of patients with a concentration of 25(OH)-vitamin D below 30nmol/l. We evaluated vascular risk parameters as blood pressure, arterial stiffness, lipid profile and glucose metabolism. Patients received vitamin D supplements for 3 months, after which the previous parameters were reassessed.

RESULTS

A total of 32 patients were included. Those with PTH over 65pg/ml were older, had worse renal function, higher systolic blood pressure, pulse pressure and arterial stiffness. Treatment with vitamin D showed a statistically significant trend to lower blood pressure and pulse wave velocity.

CONCLUSIONS

The increase in PTH in patients with low vitamin D involves poor control of blood pressure and increased vascular stiffness. Vitamin D replacement shows a tendency to reduce these parameters.