Effect of vitamin D supplementation on health status in non-vitamin D deficient people with type 2 diabetes mellitus.

OBJECTIVE: Increased levels of depressive symptoms, fatigue or pain (all dimensions of reduced health-related quality of life (HRQOL)) are common in people with type 2 diabetes mellitus (DM). Earlier studies have reported associations between low vitamin D status and fatigue and depressive symptoms. The aim of the present study was to examine the effects of vitamin D supplementation on dimensions of HRQOL in people with type 2 DM. DESIGN: Randomised, double-blind, placebo-controlled trial. METHODS: The effect of monthly cholecalciferol 50,000 IU vs placebo on HRQOL was assessed in 275 adults with type 2 DM derived from general practices. HRQOL at baseline and after six months using the Short Form 36 Health Survey (SF-36) was collected. Linear regression analyses were used to compare the change in HRQOL over time between the vitamin D and placebo group. RESULTS: 187/275 (68%) completed baseline and follow-up SF-36 and were included in the analysis. Median serum 25-hydroxyvitamin D almost doubled in the intervention group compared to that in the placebo group (58.5-106.0 nmol/L vs 60.0-61.5 nmol/L, respectively). A small significant difference (adjusted B: -8.90; 95% CI: -17.16 to -0.65) between both groups was seen concerning the SF-36 domain role limitations due to physical problems in disadvantage of the vitamin D group. CONCLUSIONS: Six months of vitamin D supplementation did not improve HRQOL in non-vitamin D-deficient people with type 2 DM managed on oral antidiabetic therapy.

Vitamin D status is associated with skin autofluorescence in patients with type 2 diabetes mellitus: a preliminary report.

BACKGROUND: Skin autofluorescence is a non-invasive measurement of advanced glycation end products (AGE), which are suggested to be one of the major agents in the pathogenesis and progression of diabetes related cardiovascular complications. Recently, low vitamin D status has been linked to the progression of type 2 diabetes mellitus (T2DM) and cardiovascular disease. The aim of this study is to investigate the association between vitamin D status and skin autofluorescence in patients with T2DM. METHODS: In this preliminary report skin autofluorescence was measured non-invasively with an AGE-reader in 245 patients with T2DM treated with lifestyle advice, metformin and/or sulphonylurea-derivatives. All patients were randomly assigned to receive either vitamin D 50,000 IU/month or placebo for 6 months. RESULTS: Skin autofluorescence was significantly higher in patients with a serum 25(OH)D < 50 nmol/l compared to patients with a serum 25(OH)D > 75 nmol/l (2.81 versus 2.41; p < 0.001). Mean serum 25(OH)D was 60.3 ± 23.4 nmol/l and was independently associated with skin autofluorescence (ß -0.006; p < 0.001). Mean vitamin D increased from 60.8 to 103.6 nmol/l in the intervention group, however no effect was seen on accumulation of skin AGEs after 6 months compared to placebo. CONCLUSIONS: Vitamin D status is independently associated with skin auto fluorescence in patients with well-controlled T2DM. No effect was seen on the amount of skin AGEs after a short period of 6 months vitamin D supplementation. Further research with longer follow-up and measurement of circulating advanced glycation end products is needed to elucidate the causality of the association.

Ain't No Sunshine When She's Gone: Pseudohypoparathyroidism Discovered in an Adult.

An 18-year-old negroid woman presented with progressive cramps in both hands. She was Jamaican and had moved to The Netherlands 8 months before. On physical examination Trousseau's sign was positive. Laboratory analysis showed severe hypocalcaemia (1.17 mmol/L) and hyperphosphatemia (2.0 mmol/L). Urinary excretion of both calcium (0.8 mmol/day) and phosphate (5 mmol/day) was low, as is seen in hypoparathyroidism. However, the PTH level was increased (22.1 pmol/L), whereas 25-(OH)-vitamin D was low (31 nmol/L). An Ellsworth-Howard test showed only a fivefold increase in urinary phosphate excretion after administration of synthetic PTH, supporting the diagnosis pseudohypoparathyroidism. Upon treatment with calcium supplementation and alfacalcidol, her symptoms disappeared. Pseudohypoparathyroidism (PHP) is a rare hereditary disorder resembling hypoparathyroidism, although plasma PTH levels are elevated. PHP is caused by alterations in the PTH receptor, inducing target tissue resistance to PTH. This results in hypocalcaemia and hyperphosphatemia, while PTH levels are elevated. The diagnosis is confirmed by the Ellsworth-Howard test, which will show a 100-fold increase in phosphate excretion if the PTH receptor functions properly. Treatment is lifelong supplementation of calcium and alfacalcidol. In our patient, symptoms were probably evoked by the lack of sunlight in Dutch winter, decreasing vitamin D levels and thereby aggravating hypocalcaemia.

Vitamin D and gestational diabetes: a systematic review and meta-analysis.

BACKGROUND: Conflicting results currently exists on the association between vitamin D and glucose metabolism. The role of maternal vitamin D status in gestational diabetes mellitus (GDM) is not clear. This meta-analysis aimed to examine this role in women with GDM compared with normal glucose tolerance (NGT). METHODS: We performed a systematic review and meta-analysis by searching MEDLINE database, the Cochrane library and Uptodate® Online for English-language literature up to September 2011. Summary odds ratios were calculated using a random-effects model meta-analysis. RESULTS: Seven observational studies were eligible for the meta-analysis, including 2146 participants of whom 433 were diagnosed with GDM. Four studies reported a high incidence of vitamin D deficiency in pregnant women (>50%). Overall vitamin D deficiency (serum 25-hydroxyvitamin D (25OHD)<50 nmol/l) in pregnancy was significantly related to the incidence of GDM with an odds ratio of 1.61 (95% CI 1.19-2.17; p=0.002). Serum 25OHD was significant lower in participants with GDM than in those with NGT (-5.33 nmol/l (95% CI -9.73 to -0.93; p=0.018). CONCLUSIONS: This meta-analysis indicates a significant inverse relation of serum 25OHD and the incidence of GDM. However, it remains unclear whether this association is causal due to the observational study design of the studies. Clinical trials are needed to examine whether vitamin D supplementation will improve glycemic control in women with GDM.