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Vitamin D status and its association with parathyroid hormone concentrations in women of child-bearing age living in Jakarta and Kuala Lumpur

Green TJ, Skeaff CM, Rockell JE, Venn BJ, Lambert A, Todd J, et al.

Eur J Clin Nutr, 2008 Mar;62(3):373-8.
PMID: 17342165

OBJECTIVE: To describe the vitamin D status of women living in two Asian cities,--Jakarta (6 degrees S) and Kuala-Lumpur (2 degrees N), to examine the association between plasma 25-hydroxyvitamin D and parathyroid hormone (PTH) concentrations, and to determine a threshold for plasma 25-hydroxyvitamin D above which there is no further suppression of PTH. Also, to determine whether dietary calcium intake influences the relationship between PTH and 25-hydroxyvitamin D.
DESIGN: Cross-sectional.
SETTING: Jakarta, Indonesia and Kuala Lumpur, Malaysia.
PARTICIPANTS: A convenience sample of 504 non-pregnant women 18-40 years.
MAIN MEASURES: Plasma 25-hydroxyvitamin D and PTH.
RESULTS: The mean 25-hydroxyvitamin D concentration was 48 nmol/l. Less than 1% of women had a 25-hydroxyvitamin D concentration indicative of vitamin D deficiency (<17.5 nmol/l); whereas, over 60% of women had a 25-hydroxyvitamin D concentration indicative of insufficiency (<50 nmol/l). We estimate that 52 nmol/l was the threshold concentration for plasma 25-hydroxyvitamin D above which no further suppression of PTH occurred. Below and above this concentration the slopes of the regression lines were -0.18 (different from 0; P=0.003) and -0.01 (P=0.775), respectively. The relation between vitamin D status and parathyroid hormone concentration did not differ between women with low, medium or high calcium intakes (P=0.611); however, even in the highest tertile of calcium intake, mean calcium intake was only 657 mg/d.
CONCLUSION: On the basis of maximal suppression of PTH we estimate an optimal 25-hydroxyvitamin D concentration of approximately 50 nmol/l. Many women had a 25-hydroxyvitamin D below this concentration and may benefit from improved vitamin D status.

Matched MeSH terms: Vitamin D Deficiency/physiopathology*
Effects of 1α-Calcidol (Alfacalcidol) on Microvascular Endothelial Function, Arterial Stiffness, and Blood Pressure in Type II Diabetic Nephropathy Patients

Munisamy S, Daud KM, Mokhtar SS, Rasool AH

Microcirculation, 2016 Jan;23(1):53-61.
PMID: 26749451 DOI: 10.1111/micc.12256

To determine the effects of six months alfacalcidol on microvascular endothelial function, arterial stiffness, and BP in DN patients.

Matched MeSH terms: Vitamin D Deficiency/physiopathology
Vitamin D deficiency attenuates endothelial function by reducing antioxidant activity and vascular eNOS expression in the rat microcirculation

Wee CL, Mokhtar SS, Banga Singh KK, Rasool AHG

Microvasc Res, 2021 Nov;138:104227.
PMID: 34324883 DOI: 10.1016/j.mvr.2021.104227

This study examined the effects of vitamin D deficiency on vascular function and tissue oxidative status in the microcirculation; and whether or not these effects can be ameliorated with calcitriol, the active vitamin D metabolite. Three groups (n = 10 each) of male Sprague Dawley rats were fed for 10 weeks with control diet (CR), vitamin D-deficient diet without (DR), or with oral calcitriol supplementation (0.15 μg/kg) for the last four weeks (DSR). After 10 weeks, rats were sacrificed; mesenteric arterial rings were studied using wire myograph. Oxidative stress biomarkers malondialdehyde (MDA) levels and superoxide dismutase (SOD) activity were measured in the mesenteric arterial tissue. Vascular protein expression of endothelial nitric oxide synthase (eNOS) was determined by Western blotting. Acetylcholine-induced endothelium-dependent relaxation of DR was lower than CR. eNOS expression and SOD activity were lower in mesenteric arterial tissue of DR compared to CR. Calcitriol supplementation to DSR did not ameliorate the above parameters; in fact, augmented endothelium-dependent contraction was observed. Serum calcium was higher in DSR compared to CR and DR. In conclusion, vitamin D deficiency impaired microvascular vasodilation, associated with eNOS downregulation and reduced antioxidant activity. Calcitriol supplementation to vitamin D-deficient rats at the dosage used augmented endothelium-dependent contraction, possibly due to hypercalcaemia.

Matched MeSH terms: Vitamin D Deficiency/physiopathology
Impaired microvascular endothelial function in vitamin D-deficient diabetic nephropathy patients

Munisamy S, Kamaliah MD, Suhaidarwani AH, Zahiruddin WM, Rasool AH

J Cardiovasc Med (Hagerstown), 2013 Jun;14(6):466-71.
PMID: 22964652 DOI: 10.2459/JCM.0b013e3283590d3d

AIMS: This study aims to compare microvascular endothelial function between vitamin D-deficient and nondeficient groups of patients with diabetic nephropathy. Serum levels of the inflammatory marker high-sensitivity C-reactive protein (hsCRP) were also measured.
METHODS: This prospective cross-sectional study involved 70 patients with diabetic nephropathy; 40 were categorized into the group with nondeficient serum 25-hydroxyvitamin D levels [25(OH)D >50 nmol/l], whereas 30 patients were categorized to the group with deficient serum 25(OH)D (<50 nmol/l). Microvascular endothelial function was determined using laser Doppler fluximetry and the process of iontophoresis. Acetylcholine and sodium nitroprusside were used to determine endothelium-dependent and independent vasodilatation.
RESULTS: Mean age of patients was 56.7 ± 3.8 years; 50 were men, whereas 20 were women. Mean serum 25(OH)D in the vitamin D-nondeficient group was 69.4 ± 2.9 nmol/l; the level in the vitamin D-deficient group was 42.1 ± 1.3 nmol/l, P < 0.001. Endothelium-dependent vasodilatation was lower in the vitamin D-deficient group compared with the vitamin D-nondeficient group (23.6 ± 2.7 versus 37.3 ± 3.8 arbitrary units, P = 0.004). No significant differences were observed between the two groups in their hsCRP levels, mean age, estimated glomerular filtration rate, systolic blood pressure (SBP) and diastolic blood pressure (DBP) and glycosylated haemoglobin.
CONCLUSION: Microvascular endothelial function was significantly reduced in diabetic nephropathy patients with deficient vitamin D levels compared with those with nondeficient levels.

Matched MeSH terms: Vitamin D Deficiency/physiopathology*
Fulltext The Consumption of Dairy and Its Association with Nutritional Status in the South East Asian Nutrition Surveys (SEANUTS)

Nguyen Bao KL, Sandjaja S, Poh BK, Rojroongwasinkul N, Huu CN, Sumedi E, et al.

Nutrients, 2018 Jun 13;10(6).
PMID: 29899251 DOI: 10.3390/nu10060759

Despite a major decrease in undernutrition worldwide over the last 25 years, underweight and stunting in children still persist as public health issues especially in Africa and Asia. Adequate nutrition is one of the key factors for healthy growth and development of children. In this study, the associations between dairy consumption and nutritional status in the South East Asian Nutrition Survey (SEANUTS) were investigated. National representative data of 12,376 children in Indonesia, Malaysia, Thailand, and Vietnam aged between 1 and 12 years were pooled, representing nearly 88 million children in this age category. It was found that the prevalence of stunting and underweight was lower in children who consumed dairy on a daily basis (10.0% and 12.0%, respectively) compared to children who did not use dairy (21.4% and 18.0%, respectively) (p < 0.05). The prevalence of vitamin A deficiency and vitamin D insufficiency was lower in the group of dairy users (3.9% and 39.4%, respectively) compared to non-dairy consumers (7.5% and 53.8%, respectively) (p < 0.05). This study suggests that dairy as part of a daily diet plays an important role in growth and supports a healthy vitamin A and vitamin D status.

Matched MeSH terms: Vitamin D Deficiency/physiopathology