Vitamin D status and health-related quality of life in patients with Type 2 diabetes.

AIMS: To test whether vitamin D status was associated with health-related quality of life in people with Type 2 diabetes mellitus. METHODS: Demographic and clinical characteristics, including health-related quality of life scores, were obtained from 241 adult patients with Type 2 diabetes managed with oral hypoglycaemic agents. Health-related quality of life was assessed using the Short-Form 36 Health Survey. Multiple logistic regression analysis was used to investigate the association between vitamin D status and health-related quality of life, with adjustment for confounders. RESULTS: The mean age of the patients included in the study was 67 ± 8 years. Their mean HbA1c concentration was 52 ± 8 mmol/mol (6.9 ± 0.7%) and their mean serum 25-hydroxyvitamin D concentration was 59 ± 23 nmol/l. Vitamin D deficiency (serum 25-hydroxyvitamin D < 50 nmol/l) was present in 38% of patients. No significant associations were found between vitamin D status and health-related quality of life. CONCLUSIONS: Vitamin D status was not associated with health-related quality of life in patients with Type 2 diabetes. This could be explained by the relatively high serum 25-hydroxyvitamin D concentration, good glycaemic control and relatively good health-related quality of life of all patients. A prospective study among patients with vitamin D deficiency and poor glycaemic control would be interesting for future research.

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.

Vitamin D and metabolic disturbances in polycystic ovary syndrome (PCOS): A cross-sectional study.

OBJECTIVE: To compare vitamin D status in women with PCOS versus fertile women and subsequently evaluate the association between vitamin D status and metabolic disturbances in PCOS women. METHODS: We conducted a cross-sectional comparison study of 639 women with PCOS and 449 fertile women. Serum 25-hydroxyvitamin D (25(OH)D) was stratified into a severe deficient (< 25 nmol/l), insufficient (25-50 nmol/l), moderate (50-75 nmol/l) and adequate (> 75 nmol/l) status. The main outcome measures were the difference in vitamin D status between PCOS and fertile women, and the association between serum 25(OH)D and metabolic disturbances in PCOS women only. RESULTS: Serum 25(OH)D was significantly lower in PCOS women compared to fertile controls (mean 25(OH)D of 49.0 nmol/l versus 64.5 nmol/l). An adjusted significant difference was seen between serum 25(OH)D and homeostasis model assessment (HOMA-IR) (ß = 0.76; 95% CI: 0.63-0.91; p < 0.01), HDL-cholesterol (ß = 0.20; 95% CI: 0.05-0.60, p < 0.01) and apolipoprotein A1 (ß = 26.2; 95% CI: 7.5-45.0, p < 0.01) between the highest vitamin D group compared to the lowest vitamin D group. CONCLUSIONS: This study demonstrates that women with PCOS have a significantly lower serum 25(OH)D compared to fertile controls. A compromised vitamin D status in PCOS women is associated with a higher HOMA-IR and an unfavourable lipid profile. Large randomized controlled trials are necessary to explore the causality of this linkage.

A compromised maternal vitamin D status is associated with congenital heart defects in offspring.

BACKGROUND: Interactions between genetic and environmental factors, including modifiable maternal nutrition and lifestyle, play a significant role in the pathogenesis of most congenital heart defects (CHD). The aim of this study was to investigate associations between periconceptional maternal vitamin D status and the prevalence of CHD in offspring. METHODS: A case-control study was performed in 345 mothers of a child with CHD and 432 mothers of a child without CHD from four tertiary hospitals in the Netherlands between 2003 and 2005. Approximately 15months after pregnancy mothers filled out questionnaires regarding general characteristics and periconceptional lifestyle. Maternal blood was obtained to determine serum 25-hydroxyvitamin D and lipid concentrations. The 25-hydroxyvitamin D concentration was stratified into a deficient <50nmol/l, moderate 50-75nmol/l and adequate >75nmol/l status. Logistic regression was performed to study associations between vitamin D status and CHD risk, adjusted for maternal age, body mass index, ethnicity, smoking and total cholesterol concentration. RESULTS: Case mothers less often had an adequate vitamin D status compared with controls (27% vs. 38%; p=0.002). The use of multivitamin supplements, ethnicity, season and body mass index were associated with vitamin D concentrations. A moderate (odds ratio 1.58, [95%CI 1.08, 2.32]) and deficient (odds ratio 2.15, [95%CI 1.44-3.19]) vitamin D status were associated with CHD in offspring. CONCLUSION: A compromised maternal vitamin D status is associated with an approximately two-fold increased prevalence of CHD in offspring. Therefore, improvement of the periconceptional maternal vitamin D status is recommended.

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.

The role of vitamin D in metabolic disturbances in polycystic ovary syndrome: a systematic review.

CONTEXT: Metabolic disturbances, in particular, insulin resistance (IR) and dyslipidemia, are common in women suffering from polycystic ovary syndrome (PCOS). Evidence is accumulating that vitamin D status may contribute to the development of metabolic disturbances in PCOS. OBJECTIVE: The aim of this study was to carry out a systematic review addressing the association between vitamin D status, vitamin D receptor polymorphisms, and/or polymorphisms related to vitamin D metabolism and metabolic disturbances in women with PCOS. DESIGN AND METHODS: A systematic search of electronic databases was carried out up to January 2013 for observational studies and clinical trials in women suffering from PCOS with outcome measures that were related to vitamin D status. We conducted univariate and multivariate regression analyses of the weighted means to gain insights into the association between vitamin D, BMI, and IR based on existing literature. RESULTS: We found 29 eligible trials with inconsistency in their results. One well-designed randomized controlled trial has been carried out until now. Univariate regression analyses of the weighted means revealed vitamin D to be a significant and independent predictor of IR in both PCOS and control women. The significance disappeared after adjustment for BMI in PCOS women. CONCLUSIONS: Current evidence suggests an inverse association between vitamin D status and metabolic disturbances in PCOS. Owing to the heterogeneity of the studies, it is hard to draw a definite conclusion. The causal relationship between vitamin D status and metabolic disturbances in PCOS remains to be determined in well-designed placebo-controlled randomized clinical trials.

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.