Effects of vitamin D2 or D3 supplementation on glycaemic control and cardiometabolic risk among people at risk of type 2 diabetes: results of a randomized double-blind placebo-controlled trial.

AIMS: To investigate the effect of short-term vitamin D supplementation on cardiometabolic outcomes among individuals with an elevated risk of diabetes. METHODS: In a double-blind placebo-controlled randomized trial, 340 adults who had an elevated risk of type 2 diabetes (non-diabetic hyperglycaemia or positive diabetes risk score) were randomized to either placebo, 100,000 IU vitamin D2 (ergocalciferol) or 100,000 IU vitamin D3 (cholecalciferol), orally administered monthly for 4 months. The primary outcome was change in glycated haemoglobin (HbA1c) between baseline and 4 months, adjusted for baseline. Secondary outcomes included: blood pressure; lipid levels; apolipoprotein levels; C-reactive protein levels; pulse wave velocity (PWV); anthropometric measures; and safety of the supplementation. RESULTS: The mean [standard deviation (s.d.)] 25-hydroxyvitamin D [25(OH)D]2 concentration increased from 5.2 (4.1) to 53.9 (18.5) nmol/l in the D2 group, and the mean (s.d.) 25(OH)D3 concentration increased from 45.8 (22.6) to 83.8 (22.7) nmol/l in the D3 group. There was no effect of vitamin D supplementation on HbA1c: D2 versus placebo: -0.05% [95% confidence interval (CI) -0.11, 0.02] or -0.51 mmol/mol (95% CI -1.16, 0.14; p = 0.13); D3 versus placebo: 0.02% (95% CI -0.04, 0.08) or 0.19 mmol/mol (95% CI -0.46, 0.83; p = 0.57). There were no clinically meaningful effects on secondary outcomes, except PWV [D2 versus placebo: -0.68 m/s (95% CI -1.31, -0.05); D3 versus placebo -0.73 m/s (95% CI -1.42, -0.03)]. No important safety issues were identified. CONCLUSIONS: Short-term supplementation with vitamin D2 or D3 had no effect on HbA1c. The modest reduction in PWV with both D2 and D3 relative to placebo suggests that vitamin D supplementation has a beneficial effect on arterial stiffness.

Influence of a single oral dose of vitamin D(2) on serum 25-hydroxyvitamin D concentrations in tuberculosis patients.

SETTING: Newham Chest Clinic, London, UK. OBJECTIVE: To determine the safety and efficacy of the administration of bolus-dose vitamin D(2) in elevating serum 25-hydroxyvitamin D (25[OH]D) concentrations in tuberculosis (TB) patients. DESIGN: A multi-ethnic cohort of TB patients was randomised to receive a single oral dose of 2.5 mg vitamin D(2) (n = 11) or placebo (n = 14). Serum 25(OH)D and corrected calcium concentrations were determined at baseline and 1 week and 8 weeks post-dose, and compared to those of a multi-ethnic cohort of 56 healthy adults receiving an identical dose of vitamin D(2). RESULTS: Hypovitaminosis D (serum 25[OH]D < 75 nmol/l) was present in all patients at baseline. A single oral dose of 2.5 mg vitamin D2 corrected hypovitaminosis D in all patients in the intervention arm of the study at 1 week post-dose, and induced a 109.5 nmol/l mean increase in their serum 25(OH)D concentration. Hypovitaminosis D recurred in 10/11 patients at 8 weeks post-dose. No patient receiving vitamin D(2) experienced hypercalcaemia. Patients receiving 2.5 mg vitamin D(2) experienced a greater mean increase in serum 25(OH)D at 1 week post-dose than healthy adults receiving 2.5 mg vitamin D(2). CONCLUSION: A single oral dose of 2.5 mg vitamin D(2) corrects hypovitaminosis D at 1 week but not at 8 weeks post-dose in TB patients.

Circulating MMP9, vitamin D and variation in the TIMP-1 response with VDR genotype: mechanisms for inflammatory damage in chronic disorders?

BACKGROUND: Vitamin-D deficiency and vitamin-D receptor genotype (VDR) are risk factors for several disorders with inflammatory components, including coronary heart disease (CHD) and diabetes, though the mechanisms involved are unclear. AIM: To examine the hypothesis that vitamin D status modulates the matrix metalloproteinase (MMP) system in a population with a high prevalence of vitamin D deficiency, a situation affecting susceptibility to CHD and diabetes. DESIGN: Prospective cross-sectional, interventional and embedded studies. METHODS: Circulating MMP2,9, the inhibitor TIMP-1 and C-reactive protein (CRP) were measured during studies of vitamin-D deficiency as a risk factor for type 2 diabetes and CHD in 171 healthy British Bangladeshi adults, free of known diabetes or major illness. Vitamin D status, VDR genotype, body-build, blood pressure, lipid and insulin profiles, glucose tolerance, fibrinogen, PAI-1, folate and homocysteine were measured. Vitamin-D-deficient subjects were re-assessed after 1 years' supplementation. MMP, TIMP-1 and CRP levels were measured in 41 subjects halfway through 5-year follow-up. Independent determinants of circulating concentrations of MMP9, TIMP-1 and CRP were assessed by multiple regression analysis. RESULTS: Vitamin D status was the sole determinant of circulating MMP9 (inversely) and an independent determinant of CRP (inversely). Determinants of TIMP-1 were MMP9, systolic blood-pressure (directly) and VDR genotype (TaqI). Significant reductions in MMP9 (-68%), TIMP-1 (-38%) and CRP (-23%) concentrations followed vitamin-D supplementation. DISCUSSION: Vitamin-D insufficiency is associated with increased circulating MMP2,9 and CRP, correctable by supplementation. This finding provides a possible mechanism for tissue damage in chronic inflammatory conditions, including CHD and diabetes.

Peripheral blood level alterations of TIMP-1, MMP-2 and MMP-9 in patients with type 1 diabetes.

AIM: To determine the plasma levels of enzymes and inhibitors involved in extracellular matrix turnover in patients with Type 1 diabetes with normal renal function. METHODS: Plasma levels of matrix metalloproteinases 2 and 9 (MMP-2, MMP-9) and tissue inhibitor of metalloproteinase 1 (TIMP-1) were measured in 43 Type 1 diabetic subjects and age- and sex-matched controls. RESULTS: No significant difference in plasma MMP-2 between diabetic patients and controls was observed. MMP-9 was detected in the plasma of 15 diabetic patients (35%), but undetectable in all control subjects (P < 0.015). Plasma TIMP-1 concentrations were significantly elevated (P < 0.001) in diabetic patients compared to controls. There was no correlation observed between MMP-2, MMP-9 and TIMP-1 and similarly between MMP-2, MMP-9 and TIMP-1 and age, duration of diabetes, blood pressure and glycated haemoglobin (HbA1c). CONCLUSIONS: This study has demonstrated alterations in several plasma extracellular matrix modulators in the absence of significant vascular disease.

Effect of alcohol withdrawal on liver transaminase levels and markers of liver fibrosis.

BACKGROUND AND AIM: Acute alcohol withdrawal causes changes in hepatic blood flow and metabolism that may result in liver damage. This study aims to assess liver function tests and markers of hepatic fibrogenesis following alcohol withdrawal in alcoholics with clinically compensated liver disease. METHODS: Serial liver function tests and clinical assessments were performed on 22 male alcoholics during alcohol withdrawal. Plasma tissue inhibitor of metalloproteinase 1 (TIMP1), an inhibitor of collagen degradation, and plasma amino-terminal procollagen III peptide (PIIINP), a collagen precursor molecule, were measured in these alcoholics and in 11 control subjects. RESULTS: Transaminase levels did not change significantly over 7 days when all subjects were analyzed together. However, 32% of subjects showed a marked transaminase rise. These subjects did not differ from the others in baseline characteristics or short-term outcome, but had a greater benzodiazepine requirement. Only one subject consumed paracetamol (acetaminophen; 1-2 g/day). He had the largest transaminase rise. By comparing PIIINP assays, intact PIIINP concentration appears to increase following alcohol withdrawal. The TIMP1 levels were elevated in alcoholic subjects, but did not change following withdrawal. CONCLUSIONS: Increasing PIIINP suggests that hepatic fibrogenesis increases, or hepatic clearance falls, during acute alcohol withdrawal. The TIMP1 elevation in these alcoholics suggests that the inhibition of collagen degradation occurs while liver disease is still compensated. The period following alcohol withdrawal may be a time of marked increased susceptibility to paracetamol. The biochemical changes we observed were not associated with adverse short-term outcome, but the cumulative effect after repeated episodes of abrupt withdrawal may be of concern.

Alternative medicines elevate blood leads in Omani children referred for extensive investigation.

The frequency of elevated blood lead levels in Omani children referred for routine investigation was determined by measurement of 529 blood samples randomly selected from children less than 12 years old, without clinical suspicion of lead poisoning. The blood was collected from four distinct areas within the Sultanate of Oman: the Royal Hospital, a tertiary referral centre in the capital Muscat; and the district hospitals Nizwa, Sur, and Sohar. In all areas, between 22 and 45 per cent children had higher than desirable blood lead levels according to CDC criteria. The highest blood lead levels were found in the Royal Hospital, Muscat and occurred in children attending the paediatric oncology or thalassaemic clinics who were undergoing extensive investigations.