Association of serum 25-hydroxyvitamin D with type 2 diabetes and markers of insulin resistance in a general older population in Finland

Contribution of body mass index, waist circumference, and 25-OH-D3 on the risk of pre-diabetes mellitus in the Chinese population

This study aimed to investigate the associations between body mass index (BMI), waist circumference (WC), 25-hydroxy-vitamin D3 (25-OH-D3), and the risk of pre-diabetes mellitus (PDM), as well as their predictive values in identifying PDM. A total of 1688 participants were included in this cross-sectional investigation. Spearman's correlation analysis was used to assess the relationships between candidate indicators and PDM. The impact of indicators on PDM risk was determined by multivariate logistic regression. The receiver operating characteristic (ROC) analysis was performed to evaluate the prognostic value of indicators. Our study indicated a positive correlation between WC, BMI, and 25-OH-D3 and PDM. WC (OR = 1.05, 95% CI = 1.04-1.06, p < 0.001), BMI (OR = 1.11, 95% CI = 1.08-1.15, p < 0.001), and 25-OH-D3 (OR = 1.01, 95% CI = 1.00-1.02, p = 0.037) and an increased risk of PDM. Additionally, the ROC analysis demonstrated that WC (AUC = 0.651, Specificity = 55.00%, Sensitivity = 67.900%) had a higher diagnostic value for predicting PDM compared to the other variables (BMI, 25-OH-D3, TG, TC, LDL-C, HDL-C, and UA). A cut-off value of WC > 80.5 cm predicted PDM with both good sensitivity and specificity. Additionally, the cut-off value of waist circumference (WC) for men with prediabetes was 86.500, while for women with prediabetes, it was 76.500.

Additive Interaction Between Insulin Resistance, Chronic Low-Grade Inflammation and Vitamin D Deficiency on the Risk of Type 2 Diabetes Mellitus: A Cohort Study

OBJECTIVES

The aim of this study was to explore, on an additive scale, the combined effect of the association between insulin resistance (IR), chronic low-grade inflammation (CLGI) and vitamin D deficiency (VDD) on the risk of type 2 Diabetes Mellitus (T2DM).

METHODS

This is a cohort study, including 1484 non-diabetic subjects, followed for a period of four years. 25 hydroxy-vitamin D (25OHD), hypersensitive C-reactive protein (HsCRP) and triglyceride-glucose index were assessed. Based on VDD and CLGI, the population was subdivided into 4 exposure groups. Analysis was performed both in the case of IR and without IR. Cox proportional regression and additive interaction were applied to explore cumulative effects of exposure.

RESULTS

At follow-up, 162 newly diagnosed cases of T2DM were identified. TYG index (RR = 4.0[2.8-5.6]), HsCRP (RR = 1.6 [1.4-1.7]) and 25OHD (RR = 0.96 [0.39-0.98]) were all significantly associated with the risk of T2DM (p < 0.01). The highest excess risk was recorded in patients cumulating simultaneously IR, CLGI and VDD (RR= 8.4[3.6-19.8], p < 0.0001). The additive interaction was significant, the excess risk linked to the interaction RERI = 10.5[1.43-19.7], the proportion attributable to the combined effect: AP = 0.61[0.37-0.85], and the interaction was synergistic: synergy index: 2.8[1.42-5.69].

CONCLUSION

Baseline levels of TYG index, 25OHD and HsCRP are strongly predictive of future T2DM, and their joint effects are additive and synergistic. Interventional studies are therefore warranted in order to evaluate whether vitamin D supplementation, combined with appropriate anti-inflammatory therapies, is effective as a preventive strategy to reduce the risk of T2DM.

Bone Fragility in Diabetes and its Management: A Narrative Review

Bone fragility is a serious yet under-recognised complication of diabetes mellitus (DM) that is associated with significant morbidity and mortality. Multiple complex pathophysiological mechanisms mediating bone fragility amongst DM patients have been proposed and identified. Fracture risk in both type 1 diabetes (T1D) and type 2 diabetes (T2D) continues to be understated and underestimated by conventional risk assessment tools, posing an additional challenge to the identification of at-risk patients who may benefit from earlier intervention or preventive strategies. Over the years, an increasing body of evidence has demonstrated the efficacy of osteo-pharmacological agents in managing skeletal fragility in DM. This review seeks to elaborate on the risk of bone fragility in DM, the underlying pathogenesis and skeletal alterations, the approach to fracture risk assessment in DM, management strategies and therapeutic options.

Association between vitamin D status and cardiometabolic risk factors in adults with type 2 diabetes in Shenzhen, China

Background

Evidence of vitamin D status and cardiometabolic health in adults with type 2 diabetes mellitus (T2DM) is still limited. This study aimed to investigate the association between vitamin D status and cardiometabolic risk factors among adults with T2DM in Shenzhen, China.

Methods

This cross-sectional study included 164 adults (aged ≥18 years) with T2DM who were hospitalized at Peking University Shenzhen Hospital from March 1, 2023, to May 31, 2023. Serum 25-hydroxyvitamin D [25(OH)D] concentration, the active marker of vitamin D, and three major cardiometabolic risk factors including blood pressure (BP), glucose metabolism-related indicators, and blood lipid profiles were collected. Vitamin D deficiency (VDD) was defined as 25(OH)D < 20 ng/mL. Correlation, Regression, and Logistic analysis were applied to verify the association among serum 25(OH)D concentration, VDD, and 11 cardiometabolic risk factors.

Results

Median 25(OH)D concentration was 21.78 [interquartile range (IQR)=17.51-28.05] ng/mL. The prevalence of VDD was 40.24%. Serum 25(OH)D concentration was significantly negatively correlated with diastolic BP (DBP) and glycated hemoglobin A1c (HbA1c) rather than systolic BP, plasma glucose, plasma C-peptide, and blood lipid profiles among adults with T2DM in both correlation and linear regression analysis. Furthermore, the adjusted odd ratio for poor DBP control (≥90 mmHg) of T2DM patients with VDD was 3.164 (95% confidence interval=1.303, 7.683; P=0.011) compared to those without VDD.

Conclusion

In China, VDD was highly prevalent among adults with T2DM and associated with greater cardiovascular risk factors, especially with increased chances of uncontrolled DBP. These findings suggest that vitamin D levels should be monitored in T2DM patients, especially those with high DBP.

Relationship between High-density Lipoprotein Cholesterol and Insulin Resistance in Non-diabetic Chronic Kidney Disease Patients

Insulin resistance is linked to cardiovascular disease (CVD), even in non-diabetic patients. Therefore, insulin resistance contributes to the development of CVDs, which are the most important cause of morbidity and mortality in chronic kidney disease (CKD) and patients receiving dialysis replacement therapy. Furthermore, CKD greatly affects the enzyme activities responsible for the metabolism of high-density lipoprotein (HDL), causing an abnormal composition and function of HDL, which results in the loss of the anti-inflammatory effect of HDL and its protective effect against CVD. The study aimed to find the relationship between HDL-C, inflammation, and insulin resistance in nondiabetic CKD patients undergoing different modalities of treatment. This prospective cross-sectional comparative study included 80 subjects divided into the control group (20 healthy participants), Group 1 (15 predialysis CKD patients on conservative treatment), Group 2 (10 peritoneal dialysis patients), and Group 3 (35 hemodialysis patients). A full history, medical examination, and a laboratory investigation were carried out on all subjects from June 2018 to June 2019. The patient groups had significantly lower HDL and higher serum insulin than the control group. HDL was negatively correlated with the Homeostatic Model Assessment of Insulin Resistance. There was a strong negative association between HDL and insulin resistance in CKD patients. Therefore, lifestyle modifications and dyslipidemia treatment in CKD might help to prevent cardiovascular events even in nondiabetic nonobese CKD patients.

Association between the Triglyceride-Glucose Index and Vitamin D Status in Type 2 Diabetes Mellitus

BACKGROUND

Vitamin D deficiency (VDD) increases the risk for type 2 diabetes mellitus (T2DM), which might be related to insulin resistance (IR). We aimed to explore the association between the triglyceride-glucose (TyG) index, a reliable indicator of IR, and VDD in patients with T2DM.

METHODS

There were 1034 participants with T2DM enrolled in the Second Xiangya Hospital of Central South University. The TyG index was calculated as ln (fasting triglyceride (TG, mg/dL) × fasting blood glucose (mg/dL)/2). VDD was defined as 25-hydroxyvitamin D [25(OH)D] level <50 nmol/L.

RESULTS

Correlation analysis showed a negative association between the TyG index and 25(OH)D level. After adjustments for clinical and laboratory parameters, it was revealed that when taking the Q1 quartile of TyG index as a reference, an increasing trend of VDD prevalence was presented in the other three groups divided by TyG index quartiles, where the OR (95% CI) was 1.708 (1.132-2.576) for Q2, 2.041 (1.315-3.169) for Q3, and 2.543 (1.520-4.253) for Q4 (all p < 0.05).

CONCLUSIONS

Patients with higher TyG index were more likely to have an increased risk of VDD in T2DM population, which may be related to IR.

[Diagnosis and management of patients with diabetes and co-existing osteoporosis (Update 2023) : Common guideline of the Austrian Society for Bone and Mineral Research and the Austrian Diabetes Society]

Fragility fractures are increasingly recognized as a complication of both type 1 and type 2 diabetes, with fracture risk that increases with disease duration and poor glycemic control. The identification and management of fracture risk in these patients remains challenging. This manuscript explores the clinical characteristics of bone fragility in adults with diabetes and highlights recent studies that have evaluated areal bone mineral density (BMD), bone microstructure and material properties, biochemical markers, and fracture prediction algorithms (FRAX) in these patients. It further reviews the impact of diabetes drugs on bone tissue as well as the efficacy of osteoporosis treatments in this population. An algorithm for the identification and management of diabetic patients at increased fracture risk is proposed.

A Retrospective Analysis of the Relationship Between 25-OH-Vitamin D and Diabetic Foot Ulcer

Background

The fat-soluble molecule vitamin D has attracted much attention since its pleiotropism was discovered. Its effectiveness can be attributed to the presence of vitamin D receptors in most of the body's tissues. Based on the classical role of vitamin D in regulating calcium and phosphorus metabolism and maintaining bone health, the role of vitamin D in immunity, type 2 diabetes mellitus (T2DM), tumor and cardiovascular diseases has been further discovered. Some experiments have shown that vitamin D can restore the production of antimicrobial peptides (AMP) in primary diabetic foot ulcer (DFU) cells, which can improve in vitro wound healing, indicating its potential therapeutic use in DFU therapy. In addition, vitamin D can also inhibit the secretion of T-helper type 1 (Th1) cytokines IFN-Y and IL-2 while stimulating the production of Th2 cytokines, thereby promoting wound healing.

Objective

To investigate the relationship between 25-OH-vitamin D level and DFU in diabetes mellitus (DM) patients, and to provide a theoretical basis for the early prevention and treatment of DFU.

Methods

The clinical data of 429 hospitalized patients with DM were retrospectively analyzed in this case-control study. The patients were divided into the DFU group (n = 242) and non-DFU group (n = 187). Fasting venous blood was drawn from all subjects to detect serum 25-OH-vitamin D levels and blood biochemical parameters, the difference of parameters between DFU group and non-DFU group were analyzed, and the risk factors of DFU were analyzed by logistic regression.

Results

The difference between the two groups in age, DM duration, gender, diastolic blood pressure, serum creatinine, total cholesterol, triglyceride, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, alanine aminotransferase, aspartate aminotransferase, albumin, white blood cell count, hemoglobin, hematocrit, 25-OH-vitamin D was statistically significant (p < 0.05). Multivariate logistic regression analysis showed that 25-OH-vitamin D is an independent protective factor for DFU [OR 95%, CI 0.984 (0.969, 0.998), p < 0.05]. 25-OH-vitamin D nutrition status distribution was different between non-DFU group and DFU group (P < 0.05). Vitamin D deficiency (< 50 nmol/L) accounted for 86.78% of all DFU patients, which was only 74.33% in non-DFU patients. The 25-OH-vitamin D levels of DFU patients from Wagner Grades 1 to 5 showed a downward trend (p < 0.01).

Conclusion

In conclusion, our study confirms that 25-OH-vitamin D is closely correlated with DFU and that 25-OH-vitamin D is an independent protective factor for DFU. Therefore, vitamin D screening or supplementation might be beneficial to prevent DFU and improve the prognosis of DM patients.

Vitamin D Deficiency Is Associated with Glycometabolic Changes in Nondiabetic Patients with Arterial Hypertension

Recent evidence indicates that mildly increased fasting and post-oral load blood glucose concentrations contribute to development of organ damage in nondiabetic patients with hypertension. In previous studies, vitamin D deficiency was associated with decreased glucose tolerance. The aim of this study was to examine the relationships between serum 25(OH)D levels and glucose tolerance and insulin sensitivity in hypertension. In 187 nondiabetic essential hypertensive patients free of cardiovascular or renal complications, we measured serum 25-hydroxyvitamin D (25(OH)D) and parathyroid hormone (PTH) and performed a standard oral glucose tolerance test (OGTT). Patients with 25(OH)D deficiency/insufficiency were older and had significantly higher blood pressure, fasting and post-OGTT (G-AUC) glucose levels, post-OGTT insulin (I-AUC), PTH levels, and prevalence of metabolic syndrome than patients with normal serum 25(OH)D. 25(OH)D levels were inversely correlated with age, blood pressure, fasting glucose, G-AUC, triglycerides, and serum calcium and PTH, while no significant relationships were found with body mass index (BMI), fasting insulin, I-AUC, HOMA index, and renal function. In a multivariate regression model, greater G-AUC was associated with lower 25(OH)D levels independently of BMI and seasonal vitamin D variations. Thus, in nondiabetic hypertensive patients, 25(OH)D deficiency/insufficiency could contribute to impaired glucose tolerance without directly affecting insulin sensitivity.

Vitamin D supplementation and prevention of cardiovascular disease and cancer in the Finnish Vitamin D Trial: a randomized controlled trial

BACKGROUND

Vitamin D insufficiency is associated with risks of cardiovascular diseases (CVD) and cancer in observational studies, but evidence for benefits with vitamin D supplementation is limited.

OBJECTIVES

To investigate the effects of vitamin D3 supplementation on CVD and cancer incidences.

METHODS

The study was a 5-year, randomized, placebo-controlled trial among 2495 male participants ≥60 years and post-menopausal female participants ≥65 years from a general Finnish population who were free of prior CVD or cancer. The study had 3 arms: placebo, 1600 IU/day, or 3200 IU/day vitamin D3. Follow-up was by annual study questionnaires and national registry data. A representative subcohort of 551 participants had more detailed in-person investigations. The primary endpoints were incident major CVD and invasive cancer. Secondary endpoints included the individual components of the primary CVD endpoint (myocardial infarction, stroke, and CVD mortality), site-specific cancers, and cancer death.

RESULTS

During the follow-up, there were 41 (4.9%), 42 (5.0%), and 36 (4.3%) major CVD events in the placebo, 1600 IU/d (compared with placebo: HR: 0.97; 95% CI: 0.63-1.49; P = 0.89), and 3200 IU/d (HR: 0.84; 95% CI: 0.54-1.31; P = 0.44) arms, respectively. Invasive cancer was diagnosed in 41 (4.9%), 48 (5.8%), and 40 (4.8%) participants in the placebo, 1600 IU/d (HR: 1.14; 95% CI: 0.75-1.72; P = 0.55), and 3200 IU/d (HR: 0.95; 95% CI: 0.61-1.47; P = 0.81) arms, respectively. There were no significant differences in the secondary endpoints or total mortality. In the subcohort, the mean baseline serum 25-hydroxyvitamin D concentration was 75 nmol/L (SD, 18 nmol/L). After 12 months, the concentrations were 73 nmol/L (SD, 18 nmol/L), 100 nmol/L (SD, 21 nmol/L), and 120 nmol/L (SD, 22 nmol/L) in the placebo, 1600 IU/d, and 3200 IU/d arms, respectively.

CONCLUSIONS

Vitamin D3 supplementation did not lower the incidences of major CVD events or invasive cancer among older adults, possibly due to sufficient vitamin D status in most participants at baseline.

Genetic Variants Relate to Fasting Plasma Glucose, 2-Hour Postprandial Glucose, Glycosylated Hemoglobin, and BMI in Prediabetes

Diabetes mellitus (DM) is a chronic disease that seriously threatens human health. Prediabetes is a stage in the progression of DM. The level of clinical indicators including fasting plasma glucose (FPG), 2-h postprandial glucose (2hPG), and glycosylated hemoglobin (HbA1C) are the diagnostic markers of diabetes. In this genome-wide association study (GWAS), we aimed to investigate the association of genetic variants with these phenotypes in Hainan prediabetes. In this study, we recruited 451 prediabetes patients from the residents aged ≥18 years who participated in the National Diabetes Prevalence Survey of the Chinese Medical Association in 2017. The GWAS of FPG, 2hPG, HbA1C, and body mass index (BMI) in prediabetes was analyzed with a linear model using an additive genetic model with adjustment for age and sex. We identified that rs13052524 in MRPS6 and rs62212118 in SLC5A3 were associated with 2hPG in Hainan prediabetes (p = 4.35 × 10^-6, p = 4.05 × 10^-6, respectively). Another six variants in the four genes (LINC01648, MATN1, CRAT37, and SLCO3A1) were related to HbA1C. Moreover, rs11142842, rs1891298, rs1891299, and rs11142843 in TRPM3/TMEM2 and rs78432036 in MLYCD/OSGIN1 were correlated to BMI (all p < 5 × 10^-6). This study is the first to determine the genome-wide association of FPG, 2hPG, and HbA1C, which emphasizes the importance of in-depth understanding of the phenotypes of high-value susceptibility gene markers in the diagnosis of prediabetes.

Insulin Resistance Is Inversely Associated with the Status of Vitamin D in Both Diabetic and Non-Diabetic Populations

Vitamin D has been implicated in the regulation of glucose metabolism and insulin resistance. We designed this study to provide evidence that insulin resistance is dependent on the concentration of vitamin D in the body. Forty observational studies of both type 2 diabetes mellitus patients and healthy subjects were included in this meta-analysis. Related articles were searched from Embase, PubMed, and Medline through January 2021. Filters for search were used to obtain more focused results. We used Comprehensive Meta-Analysis Version 3 for the construction of forest plots. RevMan software version 5.3 was used to build the risk of bias tables and summary plots. The observational studies included in this systematic review and meta-analysis showed an inverse relationship of insulin resistance with the status of vitamin D both in non-diabetic (r = -0.188; 95% CI = -0.141 to -0.234; p = 0.000) and diabetic (r = -0.255; 95% CI = -0.392 to -0.107, p = 0.001) populations. From the meta-analysis we concluded that hypovitaminosis D is related to increased levels of insulin resistance in both type 2 diabetes patients and the healthy population all over the world.

Vitamin D Deficiency is Associated with Handgrip Strength, Nutritional Status and T2DM in Community-Dwelling Older Mexican Women: A Cross-Sectional Study

The aim of this study was to evaluate the association between handgrip strength, nutritional status and vitamin D deficiency in Mexican community-dwelling older women. A cross sectional study in women ≥ 60 years-old was performed. Plasma 25-hydroxyvitamin D (25(OH)D) concentrations were measured by a quantitative immunoassay technique. Handgrip strength was assessed using a dynamometer, while nutritional status was assessed through the Full Mini Nutritional Assessment (Full-MNA). A total of 116 women participated in the study, their mean age was 70.3 ± 5.8 years; 49.1% of the study group had plasma 25(OH)D levels lower than 40 nmol/L [16 ng/mL]. Meanwhile, 28.45% of participants had low handgrip strength (<16 kg), and 23.1% were identified at risk of malnutrition/malnourished according with Full-MNA score. Women with 25(OH)D deficiency (<40 nmol/L [16 ng/mL]) were more likely to have low handgrip strength (OR = 2.64, p = 0.025) compared with those with higher 25(OH)D values. Additionally, being malnourished or at risk of malnutrition (OR = 2.53, p = 0.045) or having type 2 diabetes mellitus (T2DM) (OR = 2.92, p = 0.044) was also associated with low 25(OH)D. The prevalence of low plasma 25(OH)D concentrations was high among Mexican active older women. Low handgrip strength, being at risk of malnutrition/malnourished, or diagnosed with T2DM was also associated with Vitamin D deficiency.

Serum 25-Hydroxyvitamin D Concentrations and Cardiometabolic Biomarkers in Chinese Rural Population

There is a paucity of data on the relation between serum 25-hydroxyvitamin D [25(OH)D] concentration and cardiometabolic biomarkers in the Chinese population. To comprehensively and quantitatively examine the association of 25(OH)D and cardiometabolic traits, we conducted a cross-sectional study in the Chinese rural population. Serum 25(OH)D and eight cardiometabolic biomarkers were measured in 1714 individuals from Henan province, China. Scatter plot was used to visualize the distribution and correlation of 25(OH)D and cardiometabolic indicators. Moreover, multivariate linear regressions and restricted cubic spline (RCS) functions were performed to examine the quantitative association between the serum 25(OH)D and cardiometabolic parameters. The median serum 25(OH)D level was 19.94 ng/ml in all participants, with an estimated 50.12% presenting vitamin D deficiency. Serum 25(OH)D level showed significantly modest association with cardiometabolic parameters (p<0.05) except for diastolic blood pressure (r=0.03, p=0.22). Multiple linear regression models showed that 25(OH)D concentration was positively associated with high-density lipoprotein cholesterol (HDL-C) and negatively associated with low-density lipoprotein cholesterol (LDL-C) and fasting serum glucose (GLU). The results of restricted cubic spline models indicated a positively linear association of 25(OH)D with HDL-C (p for overall<0.001, p for nonlinearity=0.191) and a negatively linear association with GLU (p for overall=0.024, p for nonlinearity=0.095). Overall, vitamin D deficiency was very common among Chinese rural population living near the 34 degrees north latitude. Besides, there were significant association between 25(OH)D concentrations and cardiometabolic biomarkers including HDL-C and GLU levels. Future longitudinal studies and randomized trials are warranted to clarify the causal relationship.

Vitamin D Deficiency in Elderly With Diabetes Mellitus Type 2: A Review

Diabetes mellitus type 2 (T2DM) is an emerging public health issue with high prevalence among older adults (>60 years old). Taking into consideration the great increase in the elderly population (approximately 7.5 billion worldwide), we can easily understand the impact of this chronic disease and its complications. On the other hand, vitamin D deficiency (VDD) is also a serious public health problem with significant impacts and multiple health effects. The correlation between DM and VDD has been suggested and established from many observational studies, reviews, and meta-analyses.

The literature in PubMed and Google Scholar was searched for relevant articles published up to October 2020. The keywords used were the following: vitamin D deficiency, elderly, and diabetes mellitus type 2. Among the 556 articles retrieved, 90 full texts were eligible and only 34 studies (12 retrospective studies, two prospective cohorts, three meta-analyses, seven cross-sectional studies, nine randomized control trials (RCTs), and one observational study) met the inclusion criteria for the review. The author's name, year of publication, country, type of study, and the number of patients were reported.

According to this review there is adequate evidence to support the correlation between VDD and T2DM in the elderly. The results from the RCTs are more conflicting and more studies are needed to confirm the impact of vitamin D deficiency (VD) supplementation on metabolic and lipid profile, oxidative stress, and the complications of T2DM in older patients. VDD is clearly related with severe retinopathy, diabetic peripheral neuropathy, and poor cognition performance, while there is consensus about the beneficial effect of VD on peripheral artery disease, foot ulceration prevention, and wound healing. On the other hand, there is controversy about the effect of VD supplementation on cardiovascular adverse events, endothelial function, and estimated glomerular filtration rate (eGFR). Finally, the association of VDD with fragility fractures and depression in the elderly with T2DM is currently insufficiently studied and remains controversial.

Diabetes mellitus and risk of low-energy fracture: a meta-analysis

BACKGROUND

Low-energy fracture risk is significantly increased in diabetes mellitus, the purpose of this article is to systematically evaluate the association between diabetes mellitus and risk for low-energy fracture.

METHODS

We conducted a systematic literature search of Medline, Embase, Science Citation Index, Wiley Online Library database through January 2019. Pooled relative risks (RR) with corresponding 95% confidence intervals (95% CI) were calculated with random-effects model to assess the strength of association.

RESULTS

Thirty-seven studies met the inclusion criteria, which included 3,123,382 participants. The pooled RR of any fracture in people with diabetes mellitus was 1.5 (95% CI 1.3-1.8; P < 0.05). The significant association not found in subgroup analysis of prospective design, follow-up period ≥ 10 year (all P > 0.05). The pooled RR of hip fracture in people with diabetes mellitus was 2.0 (95% CI 1.8-2.3; P < 0.05). In addition, subgroup analysis shown higher risk of hip fracture in type 1 diabetes (RR: 5.3). The pooled RR of vertebral fracture with diabetes mellitus was 1.4 (95% CI 0.9-2.2; P = 0.196). Subgroup analysis by type of diabetes showed that the RR of vertebral fracture for patients with unknown-type diabetes was 2.4 (95% CI 1.4-4.0; P < 0.05). Diabetes mellitus was associated with fractures at other sites, and effect estimates was statically significant.

CONCLUSIONS

Diabetes mellitus is an independent risk factor for low-energy fracture, and this relationship is more pronounced in hip fracture.

Decreased lung function is associated with vitamin D deficiency in apparently health, middle aged Koreans: the Kangbuk Samsung Health Study

BACKGROUND/OBJECTIVES

There has been inconsistent relationships between serum vitamin D levels and lung function in previous studies. However, previous studies included patients with medical diseases, affecting both vitamin D levels and lung function. Considering this view of potential confounders, we investigated if vitamin D deficiency (VDD) is linked to lung function in health screening examinee without overt medical conditions.

SUBJECTS/METHODS

We conducted a cohort study on 68,457 healthy Koreans (36,759 males, mean age: 37.7 years) with a health examination in 2015. Measured forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) were categorized in quartiles. To examine the relationships between VDD and lung function, adjusted odds ratios (aORs) for VDD were estimated by logistic regression.

RESULTS

Median vitamin D level was 14.9 ng/mL. The prevalence of VDD (defined as <20 ng/ml) was 74.5%. Compared with the highest quartile (Q4, reference), the aORs for VDD across decreasing quartiles (from Q3 to Q1) were 1.05, 1.06, 1.10 for FVC, and 1.07, 1.10, 1.10 for FEV1 (P for trend < 0.01 for both), in all subjects. Similarly, the aOR of having VDD for men also increased with decreasing quartiles of FVC and FEV1 in a dose-response manner (p for trend < 0.01 for both). However, neither FVC nor FEV1 was associated with VDD in women.

CONCLUSIONS

VDD was associated with decreased lung function in middle aged Korean men without overt medical conditions. VDD could be a modifiable risk factor for impaired lung function, in men but not in women.

The correlation between proinsulin, true insulin, proinsulin: True insulin ratio, 25(OH) D3, waist circumference and risk of prediabetes in Hainan Han adults

Purpose

Diabetes mellitus is a kind of highly prevalent chronic disease in the world. The intervention measures on the risk factors of prediabetes contribute to control and reduce the occurrence of diabetes. This study aimed to investigate the correlation between proinsulin (PI), true insulin (TI), PI/TI, 25(OH) D3, waist circumference (WC), and risk of prediabetes.

Methods

In this cross-sectional study, 1662 subjects including 615 prediabetes and 1047 non-prediabetes were recruited. Spearman’s correlation analysis was used to explore the association of PI, TI, PI/TI, 25(OH) D3, and waist circumference with prediabetes. Odds ratios (OR) and 95% confidence intervals (CI) were calculated by logistic regression. Receiver-Operator Characteristic (ROC) curve was used to evaluate the risk of prediabetes.

Results

Our study showed that FPI, 2hPI, FTI, 2hTI, FPI/FTI, and WC could enhance the risk of prediabetes (OR 1.034; OR 1.007; OR 1.005; OR 1.002; OR 3.577, OR 1.053, respectively; all p< 0.001). Stratified analyses indicated that FPI/FTI associated with an increased risk of prediabetes in men (OR 2.080, p = 0.042). FTI have a weak association with prediabetes risk in men and women (OR 0.987, p = 0.001; OR 0.994, p = 0.004, respectively). 2hPI could decrease prediabetes in women (OR 0.995, p = 0.037). Interesting, the sensitivity (86.0%) and AUC (0.942, p< 0.001) of combination (FPI+FTI+2hPI+2hTI+25(OH) D3+WC) were higher than the diagnostic value of these alone diagnoses. The optimal cutoff point of FPI, FTI, 2hPI, 2hTI, 25(OH) D3, and WC for indicating prediabetes were 15.5 mU/l, 66.5 mU/l, 71.5 mU/l, 460.5 mU/l, 35.5 ng/ml, and 80.5 cm, respectively. What’s more, the combination (FPI+FTI+2hPI+2hTI+25(OH) D3+WC) significantly improved the diagnostic value beyond the alone diagnoses of prediabetes in men and women (AUC 0.771; AUC 0.760, respectively).

Conclusion

The FPI, 2hPI, FTI, 2hTI, FPI/FTI, and WC significantly associated with an increased risk of prediabetes. The combination of FPI, FTI, 2hPI, 2hTI, 25(OH) D3, and WC might be used as diagnostic indicators for prediabetes.

The relationship between serum 25-hydroxyvitamin D concentration and type 2 diabetic peripheral neuropathy: A systematic review and a meta-analysis

BACKGROUND

Vitamin D is a fat-soluble vitamin that is related to the health of the human body and is an indispensable nutrient for human beings. Some studies indicated that type 2 diabetes mellitus (T2DM) with diabetic peripheral neuropathy (DPN) may be associated with vitamin D deficiency, but the current understanding of this point of view remains controversial. This study aimed to evaluate the correlation between serum 25-hydroxyl vitamin D (25 [OH] D) concentration and DPN in patients with T2DM by a meta-analysis, and to provide a reference for doctors.

METHODS

Relevant studies were selected from the PubMed, Cochrane Library, China National Knowledge Infrastructure, VIP databases, and Wanfang Data Knowledge Service Platform databases dating from 2000 to December 2017. A total of 75 articles related to serum 25 (OH) D and DPN were selected from 2000 to December 2017. Based on the inclusion and exclusion criteria of the literature, a quality assessment was conducted using the Newcastle-Ottawa scale, and a meta-analysis was performed by RevMan5.3 statistical software.

RESULTS

Thirteen studies that involved a total of 2814 type 2 diabetic patients were finally included into the meta-analysis. Meta-analysis results, heterogeneity test showed that, P < .000 01, I = 92%, calculation by random effect model revealed that, the serum concentration of 25 (OH) D in T2DM combined with DPN group was lower than that in the group without DPN (weighted mean difference = -0.74, 95% confidence interval: -1.03 to -0.46) CONCLUSIONS:: Vitamin D is associated with type 2 DPN (DPN), and vitamin D deficiency can lead to an increased risk of type 2 DPN. However, more high-quality research is needed.

The prevalence of vitamin D deficiency among patients with type 2 diabetes seen at a referral hospital in Kenya

Introduction

The prevalence of diabetes mellitus is rising at an alarming rate, calling for more insights into its pathogenetic mechanisms, and other factors involved in its progression. The prevalence of vitamin D deficiency is higher in diabetic compared to non-diabetic patients, and is associated with poor glycaemic control. This has not been documented among diabetic patients in Kenya. Aims: to determine the prevalence of hypovitaminosis D among type 2 diabetic patients at Kenyatta National Hospital in Nairobi, Kenya.

Methods

We recruited type 2 diabetic patients on follow-up at Kenyatta National Hospital. Measurements of height, weight and waist/hip ratios were taken. We drew 6mls of peripheral blood to determine vitamin D, zinc and HbA1c levels.

Results

A total of 151 participants were recruited, with 69.5% females and mean age of 58.2 years. Hypertension was found in 72.8% of the participants, and obesity in 37.7%. The mean HbA1c levels were 8.46%, and 62.9% had poor glycaemic control. The mean vitamin D level was 31.40ng/ml. Vitamin D deficiency and insufficiency was found in 38.4% and 21.9% of the participants respectively. We found a significant inverse correlation between vitamin D and glycaemic control (r = -0.09, p = 0.044) and vitamin D and BMI (r = - 0.145, p = 0.045).

Conclusion

In this study population on long-term follow-up for diabetes, there was high prevalence of vitamin D deficiency. This forms a basis for further management of patients with poor glycaemic control. Further studies are needed to document the causal association between poor glycaemic control and vitamin D deficiency.

[Diagnosis and management of patients with diabetes and co-existing osteoporosis (Update 2019) : Common guideline of the Autrian Society for Bone and Mineral Research and the Austrian Diabetes Society]

Fragility fractures are increasingly recognized as a complication of both type 1 and type 2 diabetes, with fracture risk that increases with disease duration and poor glycemic control. The identification and management of fracture risk in these patients remains challenging. This manuscript explores the clinical characteristics of bone fragility in adults with diabetes and highlights recent studies that have evaluated areal bone mineral density (BMD), bone microstructure and material properties, biochemical markers, and fracture prediction algorithms (FRAX) in these patients. It further reviews the impact of diabetes drugs on bone tissue as well as the efficacy of osteoporosis treatments in this population. An algorithm for the identification and management of diabetic patients at increased fracture risk is proposed.

Vitamin D Status and Components of Metabolic Syndrome in Older Subjects from Northern Finland (Latitude 65°North)

INTRODUCTION

Vitamin D deficiency has been linked to the increased risk of several chronic diseases, especially in people living in the Northern Latitudes. The aim of this study was to assess the vitamin D status in older subjects born in 1945 in Northern Finland (latitude 65°North), and to examine its associations to components of metabolic syndrome (MetS).

METHODS

In this cross-sectional study, we invited 904 subjects born in 1945 from the Oulu region (Oulu45 cohort), out of an original cohort of 1332 subjects. In the cohort, plasma 25 hydroxyvitamin D (25OHD) levels were determined by an enzyme immunoassay of 263 men and 373 women, with a mean age baseline of 69±0.5 years old. We assessed the participants' usage of vitamin D supplements, as well as their lifestyle factors, using a questionnaire.

RESULTS

Nearly 80% of the subjects had low vitamin D levels [either vitamin D deficient (<50 nmol/L) or insufficient (50 - 75 nmol/L)], and only 20% of the participants had sufficient vitamin D levels (>75 nmol/L) (based on the American Endocrine Society guidelines). The low vitamin D status was associated with a high prevalence of MetS; a significantly higher number of subjects with MetS (41%) had low vitamin D levels in comparison to the non-MetS subjects (38%) (p ≤ 0.05). The subjects under vitamin D supplementation had a significantly lower incidence of MetS (42.6% vs 57.4%) and its components in comparison to the non-supplemented subjects (p ≤ 0.05).

CONCLUSIONS

Low vitamin D levels are a risk factor for MetS amongst other lifestyle factors, such as dietary habits and physical inactivity, among older subjects in the Northern Latitudes (65°North). Optimal supplementation of vitamin D, along with rich dietary sources of vitamin D, are highly recommended for older subjects as a means to positively affect, e.g., hypertension, insulin resistance, and obesity, as components of the MetS.

Diagnosis and management of bone fragility in diabetes: an emerging challenge

Fragility fractures are increasingly recognized as a complication of both type 1 and type 2 diabetes, with fracture risk that increases with disease duration and poor glycemic control. Yet the identification and management of fracture risk in these patients remains challenging. This review explores the clinical characteristics of bone fragility in adults with diabetes and highlights recent studies that have evaluated bone mineral density (BMD), bone microstructure and material properties, biochemical markers, and fracture prediction algorithms (i.e., FRAX) in these patients. It further reviews the impact of diabetes drugs on bone as well as the efficacy of osteoporosis treatments in this population. We finally propose an algorithm for the identification and management of diabetic patients at increased fracture risk.

Assessment of research waste part 2: wrong study populations- an exemplar of baseline vitamin D status of participants in trials of vitamin D supplementation

BACKGROUND

Research waste can occur when trials are conducted in the wrong populations. Vitamin D deficient populations are most likely to benefit from vitamin D supplementation. We investigated waste attributable to randomised controlled trials (RCTs) of supplementation in populations that were not vitamin D deficient.

METHODS

In December 2015, we searched Pubmed, recent systematic reviews, and three trial registries for RCTs of vitamin D with clinical endpoints in adults, and 25-hydroxvitamin D (25OHD) survey data relevant to large (N ≥ 1000) RCTs. We investigated the proportion of RCTs that studied vitamin D deficient populations, temporal trends in baseline 25OHD, and whether investigators in large RCTs considered relevant 25OHD survey data or systematic reviews in their trial justifications.

RESULTS

Of 137 RCTs of vitamin D with clinical endpoints, 118 (86%) reported baseline mean/median 25OHD, which was < 25, 25-49, 50-74, and ≥ 75 nmol/L in 12 (10%), 62 (53%), 36 (31%), and 8 (7%) RCTs, respectively. In 70% of RCTs, baseline 25OHD was > 40 nmol/L. Baseline 25OHD increased over time. Before 2006, 38%, 62%, 0% and 0% of RCTs had baseline 25OHD < 25, 25-49, 50-74, and ≥ 75 nmol/L respectively; in 2011-15, the respective proportions were 9%, 49%, 37%, and 6%. Of 12 RCTs with baseline 25OHD < 25 nmol/L, 8 had neutral findings. Of 25 large RCTs (18 completed, 7 ongoing), 1 was undertaken in a vitamin D deficient population, 3 in vitamin D insufficient populations, and 17 had, or probably will have, baseline 25OHD > 40 nmol/L. 44% (8/18) of large completed RCTs cited relevant prior population 25OHD data, and only 3/10 (30%) relevant prior systematic reviews.

CONCLUSIONS

Up to 70% of RCTs of vitamin D with clinical endpoints, 71% of large completed RCTs, and 100% of ongoing large RCTs could be considered research waste because they studied cohorts that were not vitamin D deficient.

Body Mass Index, Vitamin D, and Type 2 Diabetes: A Systematic Review and Meta-Analysis

The deficiency of vitamin D is prevalent all over the world. Studies have shown that vitamin D may play an important role in the development of obesity. The current study was conducted to quantitatively evaluate the association between serum 25-(OH) vitamin D levels and the risk of obesity in both diabetic and non-diabetic subjects. A systematic review and meta-analysis of observational studies was carried out for that purpose. We searched the Medline, PubMed, and Embase databases throughout all of March 2018. A total of fifty five observational studies for both diabetic and non-diabetic subjects were finally included in the meta-analysis. The data were analyzed by comprehensive meta-analysis software version 3 and the random effects model was used to analyze the data. The meta-analysis showed an overall inverse relationship between serum vitamin D status and body mass index (BMI) in studies of both diabetic (r = −0.173, 95% = −0.241 to −0.103, p = 0.000) and non-diabetic (r = −0.152, 95% = −0.187 to −0.116, p = 0.000) subjects. The evidence of publication bias was not found in this meta-analysis. In conclusion, the deficiency of vitamin D is associated with an increased level of BMI in the studies of both diabetic and non-diabetic subjects. Reliable evidence from well-designed future randomized controlled trials is required to confirm the findings from observational studies and to find out the potential regulatory effects of vitamin D supplementation to lower BMI.

Follicle-Stimulating Hormone Levels and Subclinical Atherosclerosis in Older Postmenopausal Women

Recent studies of perimenopausal women suggest that follicle-stimulating hormone (FSH) levels may be associated with atherosclerosis, independent of estradiol. Whether FSH is related to atherosclerosis in older postmenopausal women, who have completed the menopausal transition, remains unknown. We assessed the relationship of serum FSH and estradiol levels with carotid artery intima-media thickness (IMT) among 587 postmenopausal participants in the Kuopio Ischemic Heart Disease Risk Factor Study (Kuopio, Finland). Participants were aged 53-73 years and not using hormone therapy at baseline (1998-2001). Mean IMT was measured via high-resolution ultrasonography. We observed a significant inverse association between FSH levels and IMT. Mean IMTs among women in quartiles 1-4 of FSH were 0.94 mm, 0.91 mm, 0.87 mm, and 0.85 mm, respectively (P-trend < 0.001). After adjustment for age, estradiol, testosterone, body mass index (weight (kg)/height (m)2), lipids, and other factors, FSH levels remained significantly associated with IMT (regression coefficients for quartiles 2-4 vs. quartile 1 were -0.038, -0.045, and -0.062, respectively; P-trend = 0.01). Findings were strongest in women aged 64-73 years (P-trend = 0.006) and did not vary by body mass index. In contrast, estradiol levels were not related to IMT. In summary, high postmenopausal FSH levels were associated with a lower atherosclerotic burden, independent of estradiol, adiposity, and other factors. Our findings warrant replication and the further exploration of potential underlying mechanisms.

Vitamin D and diabetes mellitus: Causal or casual association?

The incidence of both type 2 and type 1 diabetes mellitus has been increasing worldwide. Vitamin D deficiency, or the awareness of its prevalence, has also been increasing. Vitamin D may have a role in the pathogenic mechanisms predisposing to type 2 diabetes by modulating insulin resistance and/or pancreatic β-cell function. Vitamin D status or elements involved in its activation or transport may also be involved in the development of type 1 diabetes mellitus through immunomodulatory role . Based on these observations a potential association between vitamin D and diabetes has been hypothesized. In this review we discuss up to date evidence linking vitamin D with the development of diabetes. Moreover, the role of vitamin D supplementation in the prevention of both types of diabetes is analysed together with its role in improving glycemic control in diabetic patients. We also address the potential role of vitamin D deficiency in the development of macro- and microvascular complications in diabetes. Finally, we provide recommendation for Vitamin D therapy in diabetes in view of current evidence and highlight areas for potential future research in this area.

Vitamin D status and its association with insulin resistance among type 2 diabetics: A case -control study in Ghana

Background

Vitamin D plays a major role in physiological processes that modulate mineral metabolism and immune function with probable link to several chronic and infectious conditions. Emerging data suggests a possible influence of vitamin D on glucose homeostasis. This study sought to provide preliminary information on vitamin D status among Ghanaian type 2 diabetics and assessed its association with glucose homeostasis.

Methods

In a case control study, 118 clinically diagnosed Type 2 Diabetes Mellitus (T2DM) patients attending Diabetic Clinic at the Nkawie Government Hospital were enrolled between October and December 2015. Hundred healthy non-diabetics living in Nkawie district were selected as controls. Structured questionnaires were administered to obtain socio-demographic data. Venous blood samples were taken from both cases and controls to estimate their FBG, Lipid profile spectrophotometrically and IPTH, 25OHD by ELISA. Statistical analyses were performed using SPSS v20.0 Statistics.

Results

The average age of the study participants was 58.81years for cases and 57.79year for controls. There was vitamin D deficiency of 92.4% among T2DM cases and 60.2% among the non diabetic controls. Vitamin D deficiency did not significantly associate with HOMA-β [T2DM: r² = 0.0209, p = 0.1338 and Control: r² = 0.0213, p = 0.2703] and HOMA-IR [T2DM: r² = 0.0233, p = 0.1132 and Control: r² = 0.0214, p = 0.2690] in both the controls and the cases.

Conclusion

Vitamin D deficiency is prevalent in both T2DM and non-diabetics. There is no association between vitamin D deficiency and insulin resistance or beta cell function in our study population. Vitamin D supplementation among type 2 diabetics is recommended.

Study of Glycated Haemoglobin (HbA1c) In Non-Diabetic Subjects with Subclinical Hypothyroidism

INTRODUCTION

India has the higher prevalence of prediabetes, diabetes and hypothyroidism. Subclinical Hypothyroidism (SH) is more prevalent in the females than in the males. Studies have shown the elevated HbA1c in the non-diabetic hypothyroid patients. SH is defined by normal serum triiodothyronine (T₃), thyroxine (T₄) levels and serum Thyroid Stimulating Hormone (TSH) level falling between 4.2 to 10 mU/L.

AIM

To study the HbA1c level in the non-diabetic SH patients and to compare the HbA1c level with the controls.

MATERIALS AND METHODS

This case-control study was conducted on 200 subjects. A total of 100 subjects of the SH without diabetes were selected on the basis of the serum TSH (> 4.2 to < 10 mU/L), Fasting Blood Sugar (FBS) (< 110 mg/dl) level and another 100 age and sex matched normal healthy individuals were selected as the control. The HbA1c levels were measured using Immunoturbidimetry method in the Cobas Integra 400 plus. An independent t-test is applied to find out the statistically significant difference in the level of HbA1c in the case and the control groups.

RESULTS

Subjects with the non-diabetic SH had a significant higher level (5.70±0.35 %) of the HbA1c than the controls (5.26±0.17 %) (p<0.0001). There was no significant difference between the cases and the controls for the age, sex, FBS, vitamin D₃, Haemoglobin (Hb), serum T₃ and serum T₄ levels.

CONCLUSION

Our data suggest that the non-diabetic subjects with SH show misleadingly high levels of the HbA1c. Therefore, the effect of altered levels of the serum TSH on the HbA1c must be considered when interpreting the HbA1c for the diagnosis of diabetes in the SH patients.

The role of vitamin D, obesity and physical exercise in regulation of glycemia in Type 2 Diabetes Mellitus patients

AIM

The aims of this study were to determine the role of vitamin D, obesity and physical exercise in the regulation of glycemia in Type 2 Diabetes Mellitus patients in a highly consanguineous population.

DESIGN

Case and control study.

SETTING

The survey was carried out at the Hamad General Hospital and Primary Health Care (PHC) centers in the State of Qatar.

SUBJECTS

The study was conducted from November 2012 to June 2014 among subjects above 30 years of age. Of the 2224 registered with diagnosed diabetes and free diseases attending Hamad General Hospital and PHC centers agreed and gave their consent to study.

METHODS

Questionnaire included socio-demographic variables, body mass index (BMI), consanguinity, lifestyle habits, family history of diabetes, blood pressure and development of diabetes complications such as retinopathy, nephropathy, and neuropathy were collected at regular intervals throughout the follow-up. Univariate and multivariate statistical analysis were performed.

RESULTS

There were statistically significant difference between patients with diabetic and control in terms of ethnicity (p=0.012), level of education (p=0.002), occupation (p<0.001), monthly income (p<0.001), BMI(p=0.024), sport activity (p=0.018), cigarette smoking (p<0.001), consanguinity (p=0.029) and family history of Diabetes Mellitus (p<0.001) and co-morbidity hypertension (p=0.041). Further, the biochemistry values in the studied subjects with T2DM compared to healthy controls and the study revealed that serum Vitamin D, BMI, fasting glucose level, calcium, HbA1c, total cholesterol HDL, LDL, bilirubin, triglycerides, uric acid and blood pressure systolic and diastolic were higher in T2DM compared to their counterparts. Multivariate logistic regression showed that vitamin D deficiency ng/mL, Family History of T2DM, BMI (kg/m²) hypertension, consanguinity, income, mother occupation, ethnicity, educational level and Lack of physical exercise variables were significant predictors of diabetes. In the group of Diabetes Mellitus Type 2 patients, 39.3% as opposed to 51.2% in the control group had vitamin D deficiency, 25(OH) D3 levels≤10ng/ml (p<0.001). In the group of Diabetes Mellitus Type 2 patients, 34.6% as opposed to 37.9% in the control group had vitamin D insufficiency, 25(OH)D3 levels <20ng/ml (p < 0.001). In the group of Diabetes Mellitus Type 2 patients, 22.8% as opposed to 14.2% in the control group had vitamin D sufficiency, 25(OH)D3 levels >30 10ng/ml (p < 0.001).

CONCLUSION

Vitamin D, family history of diabetes, consanguinity marriages' and hereditary gene-environment interactions and physical exercise may also contribute to the current diabetes epidemic in Qatari's Arab populations.

High levels of serum vitamin D are associated with a decreased risk of metabolic diseases in both men and women, but an increased risk for coronary artery calcification in Korean men

Background

There are conflicting results for relationships between serum vitamin D levels and metabolic diseases. The aim of this study was to investigate whether serum vitamin D levels were associated with various metabolic diseases including insulin resistance (IR), metabolic syndrome (MS), fatty liver (FL), and coronary artery calcification (CAC), along with assessing gender differences for these relationships in Korean adults.

Methods

A total of 180,918 subjects (98,412 men and 82,506 women) who participated in a comprehensive health examination in the 2012–2013 period at Kangbuk Samsung Hospital, College of Medicine, Sungkyunkwan University were included. Serum vitamin D and metabolic markers were analyzed and CAC was estimated. Subjects were divided according to quartile groups of serum vitamin D. To examine the relationships of serum vitamin D to metabolic diseases and metabolic factors, multivariate logistic analysis was conducted.

Results

High levels of serum vitamin D was associated with lower ORs for MS, IR and FL both in men and women (all p < 0.05). For men, ORs for CAC were significantly higher in third and the highest quartile groups for serum vitamin D in all the analyzed models (all p < 0.05). However, women showed no significant results between serum vitamin D and CAC.

Conclusions

High levels of serum vitamin D were associated with lower risk of MS, IR and FL in both Korean men and women, but were associated with higher risk of CAC only in men, and not in women.

Electronic supplementary material

The online version of this article (doi:10.1186/s12933-016-0432-3) contains supplementary material, which is available to authorized users.

Correlation between vitamin D levels and muscle fatigue risk factors based on physical activity in healthy older adults

PURPOSE

The purpose of this study was to investigate the relationship of serum vitamin D levels with physical activity, obesity, muscle fatigue biomarkers, and total antioxidant capacity (TAC) in healthy older adults.

METHODS

A total of 85 healthy older subjects aged 64-96 years were recruited in this study. Based on estimated energy expenditure scores, the participants were classified into three groups: inactive (n=25), moderate (n=20), and physically active (n=35). Serum 25(OH)D (25-hydroxy vitamin D) levels, metabolic syndrome parameters, TAC activity, muscle fatigue biomarkers (Ca, creatine kinase, lactic acid dehydrogenase, troponin I, hydroxyproline), physical activity, body fatness, and fatigue score (visual analog scale) were estimated using immunoassay techniques and prevalidated questionnaires, respectively.

RESULTS

Physical activity was estimated in 64.6% of the participants. Males showed higher physical activity (42.5%) compared to females (26.25%). Compared to participants with lower activity, significant reduction in body mass index, waist circumference, hips, fasting blood sugar, triglycerides, total cholesterol, HDL-cholesterol, and LDL-cholesterol were observed in moderate and physically active participants. Also, significant increase in the levels of serum 25(OH)D concentrations, calcium, and TAC activity along with reduction in the levels of muscle fatigue biomarkers: creatine kinase, lactic acid dehydrogenase, troponin I, hydroxyproline, and fatigue scores (visual analog scale) were reported in physically active participants compared to those of lower physical activity. In all participants, serum 25(OH)D concentrations correlated positively with Ca, TAC, physical activity scores, and negatively with body mass index, lipid profile, fatigue scores (visual analog scale), and muscle fatigue biomarkers. Stepwise regression analysis showed that serum 25(OH)D concentrations, physical activity, Ca, TAC, and demographic parameters explained approximately 61.4%-85.8% of reduction in both fatigue scores and muscle fatigue biomarkers with substantial improvement in muscle performance in healthy older adults.

CONCLUSION

The data showed that considerable levels of 25(OH)D concentrations, calcium intake, and lower obesity positively correlated with the improvement in the muscle relief and performance of physically active participants. These results demonstrate that 25(OH)D concentrations and calcium might prevent muscle fatigue by regulation of the biosynthesis of creatine kinase, lactic acid dehydrogenase, troponin I, and hydroxyproline via a proposed antifree radical mechanism reported by higher TAC activity. It was suggested that vitamin D status could be reported as a marker of the improvement of muscle performance, especially in healthy older adults with lower physical activity.

The Effect of Vitamin D Supplementation on Glycemic Control and Lipid Profile in Patients with Type 2 Diabetes Mellitus

AIM

The aim of this study was to evaluate the effect of vitamin D supplementation in patients with type 2 diabetes mellitus (T2DM) with regard to their glycemic control and lipid profile.

METHODS

One hundred subjects with T2DM were recruited and given 4500 IU/day of vitamin D for 2 months. 25-Hydroxyvitamin D [25(OH)D], fasting blood glucose (FBG), glycosylated hemoglobin A1c (HbA1c), and lipid profile were measured pre- and postsupplementation.

RESULTS

There was a significant increase in the mean value of 25(OH)D level after supplementation (baseline level 16 ± 5.3 ng/ml vs. after supplement level 49.2 ± 17.7 ng/ml, p < 0.05). Both FBG and HbA1c but not lipid profile were significantly decreased after supplementation. However, the univariate general linear model between 25(OH)D percentiles and lipid profile levels showed that diabetic subjects with high 25(OH)D levels (>61 ng/ml) had significantly lower levels of total cholesterol and low-density lipoprotein cholesterol (LDL-C) in comparison to those in the low or middle percentiles. Furthermore, participants in a higher percentile had a significantly higher level of high-density lipoprotein cholesterol (HDL-C) than those in the middle percentile. Lipid profile levels were not affected by the supplement except for triglycerides (TG) levels in females, which were significantly decreased.

CONCLUSIONS

Vitamin D supplementation may be beneficial to diabetic subjects because it improved glycemic control. Diabetic subjects with high 25(OH)D levels (>61 ng/ml) had better lipid profiles.

Serum 25-hydroxyvitamin D levels and peripheral neuropathy in patients with type 2 diabetes: a systematic review and meta-analysis

BACKGROUND

Vitamin D is a multifunctional pro-hormone and has widespread actions in human body. Several studies showed a possible association between vitamin D deficiency and diabetic peripheral neuropathy (DPN) in patients with type 2 diabetes, but no definite conclusion was available.

METHODS

A systematic review and meta-analysis was performed to comprehensively assess the association between serum 25-hydroxyvitamin D [25(OH)D] levels and DPN in patients with type 2 diabetes. Data from eligible studies were pooled using meta-analysis.

RESULTS

Six studies that involved a total of 1,484 type 2 diabetic patients were finally included into the meta-analysis. Meta-analysis showed that there were obviously decreased serum 25(OH)D levels in DPN patients [weighted mean difference (WMD) = -6.36 ng/ml, 95 % confidence interval (95 % CI) -8.57 to -4.14, P < 0.00001]. Vitamin D deficiency was also significantly associated with increased risk of DPN in patients with type 2 diabetes [odds ratio (OR) 2.88, 95 % CI 1.84-4.50, P < 0.00001]. Meta-analysis of three studies with adjusted estimates showed that vitamin D deficiency was independently associated with increased risk of DPN in patients with type 2 diabetes (OR 2.68, 95 % CI 1.67-4.30, P < 0.0001). Sensitivity analysis showed that there was no obvious change in the pooled estimates.

CONCLUSION

Vitamin D is involved in the development of DPN in type 2 diabetic patients, and vitamin D deficiency is very likely to be associated with DPN in type 2 diabetic patients. Further studies are needed to validate the association between vitamin D deficiency and DPN.

Vitamin D status and its associations with components of metabolic syndrome in healthy children

AIM

High prevalence of vitamin D insufficiency/deficiency has been reported in populations of different countries. The aim of this cross-sectional study was to determine the prevalence and association of vitamin D status with components of metabolic syndrome.

METHODS

Lipid profile indices, anthropometric indices [body mass index and waist circumference (WC)], insulin resistance index (HOMA-IR), systolic blood pressure (SBP), diastolic blood pressure (DBP), C-reactive protein, intact parathyroid hormone (iPTH), and serum 25-hydroxyvitamin D [25(OH)D] concentration were evaluated in 297 healthy schoolchildren aged 7-11 years. Multivariate linear regression was used to determine independent predictors associated with low serum 25(OH)D concentrations.

RESULTS

The mean serum 25(OH)D concentration was 14.12±8.20 ng/mL (35.3±20.5 nmol/L); 96% of children had low serum 25(OH)D levels, 31.0% were deficient, and 65.0% had insufficient levels of 25(OH)D. Vitamin D deficiency was higher in girls (χ²=13.66; p=0.00); 25(OH)D level was negatively associated with WC, HOMA-IR, SBP, DBP, and iPTH. In the multivariate model, WC, DBP, and HOMA-IR were significant independent predictor of low 25(OH)D concentrations.

CONCLUSION

The prevalence of low vitamin D level in the studied healthy children was high and it is correlated with some components of metabolic syndrome. Outdoor activity for optimum sun exposure and additional studies are needed to evaluate the underlying metabolic syndrome components and hypovitaminosis D complications.

Relations of vitamin D status, gender and type 2 diabetes in middle-aged Caucasians

Vitamin D (Vit D) deficiency may be linked to the development of obesity-associated complications such as insulin resistance and type 2 diabetes. We therefore evaluated the relationship of Vit D serum concentrations with metabolic parameters and type 2 diabetes in middle-aged Caucasian men and women. One thousand six hundred and thirty-one Caucasians (832 males, 58.8 ± 9.7 years; 799 females, 59.7 ± 10.7 years) were evaluated in a cross-sectional study. Vit D status was assessed by measuring the serum concentration of 25-hydroxyvitamin D3 [25(OH)D3]. Type 2 diabetes prevalence was ascertained by medical history, fasting plasma glucose concentrations, oral glucose tolerance testing and/or glycosylated hemoglobin. Men displayed higher crude or seasonally adjusted 25(OH)D3 serum concentrations than women (24.64 ± 10.98 vs. 22.88 ± 11.6 ng/ml; P < 0.001). Strong associations between body mass index (BMI) and 25(OH)D3 were observed in both genders (P < 0.001). Seasonally adjusted levels of 25(OH)D3 revealed stronger associations with type 2 diabetes in women than men (P < 0.001). However, adjustment for BMI and other confounding variables revealed an independent inverse association of 25(OH)D3 with diabetes only in women (P < 0.001), whereas the association was abrogated in men. Using a 15 ng/ml 25(OH)D3 cutoff for binary comparison, adjusted odds ratios for having newly diagnosed or known type 2 diabetes more than doubled (2.95 [95 % CI 1.37-4.89] and 3.26 [1.59-6.68], respectively), in women below the cutoff. We conclude that in women, but not in men, low 25(OH)D3 serum levels are independently associated with type 2 diabetes. These findings suggest sex-specific effects of Vit D in the pathogenesis of type 2 diabetes.

Inverse Association between Vitamin D Status and Diabetes in a Clinic Based Sample of Hispanic Adults in Puerto Rico

BACKGROUND

Vitamin D deficiency is a public health problem around the world. Diabetes has been associated with vitamin D deficiency. We aimed to examine the association between the vitamin D status and diabetes in a clinic based sample of Hispanic adults in Puerto Rico.

METHODS

Demographics and laboratory test results for serum 25(OH)D, Fasting Blood Glucose (FBG), and Haemoglobin A1C (HbAlc) were extracted from medical records. Vitamin D status was classified as deficient (<12 ng/ml); inadequate (12-20 ng/ml); insufficient (21-29 ng/ml) and optimal (≥30 ng/ml) using serum 25(OH)D levels.

RESULTS

A total of 716 records were included in the analyses. Most were females (63.3%), with mean age of 54.1±14.9 y, mean BMI 30.1±6.3 kg/m2 and mean serum 25(OH)D levels of 24.3±8.6 ng/ml. Most were classified as diabetics (41.1%). Those with diabetes had lower 25(OH)D levels compared to pre-diabetic and normal glucose status (p<0.05). Serum 25(OH) D levels were inversely correlated to FBG and HbA1c in the total sample and in men (p<0.05). After adjusting for age, gender, BMI and seasonality, there was a greater risk of diabetes, but not prediabetes, in those with serum 25(OH)D levels <30 ng/ml. This risk increased from 1.8 times in those with vitamin D insufficiency to 4.2 times in those with vitamin D deficiency (<12 ng/ml).

CONCLUSION

Diabetes risk significantly increased as serum 25(OH)D levels decreased in this group of Hispanic adults, underscoring the importance of routinely screening high risk individuals for vitamin D deficiency and offer supplementation to normalize serum levels.

Glucose Metabolism Effects of Vitamin D in Prediabetes: The VitDmet Randomized Placebo-Controlled Supplementation Study

Epidemiological evidence suggests a role for vitamin D in type 2 diabetes prevention. We investigated the effects of vitamin D3 supplementation on glucose metabolism and inflammation in subjects with prediabetes. A 5-month randomized, double-blind, placebo-controlled intervention with three arms (placebo, 40 μg/d, or 80 μg/d vitamin D3) was carried out among sixty-eight overweight (BMI 25-35) and aging (≥60 years) subjects from Finland, with serum 25-hydroxyvitamin D3 [25(OH)D3] < 75 nmol/L and either impaired fasting glucose or impaired glucose tolerance. Analyses included 66 subjects who completed the trial. Glucose metabolism was evaluated by fasting and 2-hour oral glucose tolerance test-derived indices and glycated hemoglobin. Inflammation was evaluated by high-sensitive C-reactive protein and five cytokines. Although a dose-dependent increase in serum 25(OH)D3 over the supplementation period was observed (P trend < 0.001), there were no other statistically significant differences in changes in the 13 glucose homeostasis indicators between the study groups other than increase in the 120 min glucose concentration (P trend = 0.021) and a decreasing trend both in 30 min plasma insulin (P trend = 0.030) and glycated hemoglobin (P trend = 0.024) concentrations. A borderline statistically significant decreasing trend in interleukin-1 receptor antagonist concentration was observed (P = 0.070). Vitamin D3 supplementation does not improve glucose metabolism in ageing subjects with prediabetes but may have modest anti-inflammatory effects.

Is vitamin D deficiency a major global public health problem?

Vitamin D deficiency is a major public health problem worldwide in all age groups, even in those residing in countries with low latitude, where it was generally assumed that UV radiation was adequate enough to prevent this deficiency, and in industrialized countries, where vitamin D fortification has been implemented now for years. However, most countries are still lacking data, particularly population representative data, with very limited information in infants, children, adolescents and pregnant women. Since the number of recent publications is escalating, with a broadening of the geographic diversity, the objective of the present report was to conduct a more recent systematic review of global vitamin D status, with particular emphasis in at risk groups. A systematic review was conducted in PubMed/Medline in April-June 2013 to identify articles on vitamin D status worldwide published in the last 10 years in apparently healthy individuals. Only studies with vitamin D status prevalence were included. If available, the first source selected was population-based or representative samples studies. Clinical trials, case-control studies, case reports or series, reviews, validation studies, letters, editorials, or qualitative studies were excluded. A total of 103 articles were eligible and included in the present report. Maps were created for each age group, providing an updated overview of global vitamin D status. In areas with available data, the prevalence of low vitamin D status is a global problem in all age groups, in particular in girls and women from the Middle East. These maps also evidenced the regions with missing data for each specific population groups. There is striking lack of data in infants, children and adolescents worldwide, and in most countries of South America and Africa. In conclusion, vitamin D deficiency is a global public health problem in all age groups, particularly in those from the Middle East. This article is part of a Special Issue entitled '16th Vitamin D Workshop'.

Evidence Gap on the Prevalence of Non-conventional Risk Factors for Type 2 Diabetes in Iran

OBJECTIVES

Robust scientific evidence exists about the role of non-conventional risk factors in type 2 diabetes worldwide. The current epidemiological pattern of the disease in Iran suggests a precipitating role for these non-conventional risk factors. This review was performed to examine the research evidence suggesting a higher prevalence of non-conventional type 2 diabetes risk factors in Iran.

METHODS

MeSH keywords were applied to search several databases, including PUBMED, MEDLINE, AMED, EMBASE, Iran DOC, and the Scientific Information Database without a time limit from inception to September 2011. The quality of the non-interventional and population-based studies on Iranians included in these databases was assessed by the authors and any disagreement was resolved with consensus.

RESULTS

The literature search yielded 1847 publications, of which 62 were included in this study after eliminating non-relevant and overlapping papers. No study was found that verified a higher prevalence of the non-conventional type 2 diabetes risk factors in the Iranian population.

CONCLUSION

The identified evidence gap about the role of prominent non-conventional risk factors of type 2 diabetes in the Iranian population could be a major caveat in the application of an evidence-based approach to endorse or reject existing hypothesis about these risk factors. Studies on the prevalence of non-conventional biomarkers of type 2 diabetes among Iranians could be a promising area of research.

Association of serum 25-hydroxyvitamin D with lifestyle factors and metabolic and cardiovascular disease markers: population-based cross-sectional study (FIN-D2D)

Objectives

Low serum 25-hydroxyvitamin D (25OHD) level has been associated with an increased risk of several chronic diseases. Our aim was to determine lifestyle and clinical factors that are associated with 25OHD level and to investigate connection of 25OHD level with metabolic and cardiovascular disease markers.

Design

In total, 2868 Finnish men and women aged 45–74 years participated in FIN-D2D population-based health survey in 2007. Participants that had a serum sample available (98.4%; n = 2822) were included in this study. 25OHD was measured with chemiluminescent microparticle immunoassay method.

Results

The mean 25OHD level was 58.2 nmol/l in men (n = 1348) and 57.1 nmol/l in women (n = 1474). Mean 25OHD level was lower in the younger age groups than in the older ones (p<0.0001 both in men and women). This study confirmed that low physical activity (p<0.0001 both in men and women), smoking (p = 0.0002 in men and p = 0.03 in women) and high BMI (p<0.0001 in women) are factors that independently associate with low 25OHD level. Of the metabolic and cardiovascular disease markers high triglyceride concentration (p = 0.02 in men and p = 0.001 in women) and high apolipoprotein B/apolipoprotein A1 ratio (p = 0.04 in men and p = 0.03 in women) were independently associated with low 25OHD level.

Conclusions

Higher age did not predict lower 25OHD level in this study population of aged 45–74 years which may derive from a healthy life-style of “active pensioners”. Low physical activity and smoking came up as independent lifestyle factors associated with low 25OHD level. Defining the molecular mechanisms behind the associations of 25OHD with low physical activity and smoking are important objective in future studies. The association of 25OHD with BMI, high triglyceride concentration and apolipoprotein B/apolipoprotein A1 ratio may be related to the role of vitamin D in inflammation, but more detailed studies are needed.

Serum 25-hydroxyvitamin D and incidence of diabetes in elderly people: the PRO.V.A. study

CONTEXT

Increasing research has shown that low levels of serum 25-hydroxyvitamin (25OHD) predict the onset of diabetes, but no research is available on this issue in elderly people.

OBJECTIVE

Our objective was to examine whether low serum levels of 25OHD are associated with a higher risk of incident type 2 diabetes over a lengthy follow-up in a representative group of elderly people.

DESIGN AND SETTING

This was a population-based cohort study as part of the Progetto Veneto Anziani (Pro.V.A.) Study over a follow-up of 4.4 years in the general community.

PARTICIPANTS

PARTICIPANTS included 2227 participants (1728 with follow-up visits and 499 died during the follow-up) over 65 years of age without diabetes at baseline, of 2352 initially included.

MAIN OUTCOME MEASURE

The main outcome measure was incident diabetes.

RESULTS

There were no baseline differences in known factors for the onset of diabetes (body mass index, waist circumference, total cholesterol, renal function, and hemoglobin A1c levels) between the groups with different serum 25OHD levels (≤ 25, 25-50, 50-75, and ≥ 75 nmol/L). Over a 4.4-year follow-up, 291 individuals developed diabetes, with an incidence of 28 events per 1000 person-years. No significant difference in the incidence of diabetes emerged between the baseline 25OHD groups. Cox's regression analysis, adjusted for potential confounders, revealed no relationship between low vitamin D levels and incident diabetes during the follow-up (hazard ratio [HR] = 1.05, 95% confidence interval [CI] = 0.76-1.45, P = .77; HR = 1.44, 95% CI = 0.95-1.98, P = .12; and HR = 1.37, 95% CI = 0.87-2.16, P = .17 for those with 25OHD ≤25, 25-50, and 50-75 nmol/L, respectively).

CONCLUSION

Baseline serum concentrations of 25OHD were not associated with the incidence of diabetes in community-dwelling elderly people over a follow-up of 4.4 years.

The association between serum 25-hydroxyvitamin D concentrations and depressive symptoms in Korean adults: findings from the fifth Korea National Health and Nutrition Examination Survey 2010

The aims of this study were to examine the association between circulating vitamin D (25(OH)D) levels and depressive symptoms and to evaluate the associations between depressive symptoms and various sociodemographic factors. Data on serum 25(OH)D levels, sociodemographic factors, and information on depressive symptoms were obtained from the Korea National Health and Nutrition Examination Survey V-1 2010. A total of 3,570 Koreans aged ≥20 years were included in the statistical analysis. Subjects with depressive symptoms had lower serum levels of 25(OH)D (41.6±16.2 nmol/L) than those without (44.3±16.2 nmol/L; P-value<0.05; effect size = 0.17). In a logistic regression analysis, the 25(OH)D sufficiency group (≥50 nmol/L) revealed fewer depressive symptoms (OR, 0.72; 95% CI, 0.53-0.97; P-value = 0.032) after adjusting for multiple factors. In addition, females (OR, 3.61; 95% CI, 2.55-5.11; P-value<0.001), problematic alcohol users (OR, 2.33; 95% CI, 1.63-3.34; P-value<0.001), current smokers (OR, 1.43; 95% CI, 1.02-1.99; P-value = 0.036), and subjects who experienced weight loss (OR, 1.78; 95% CI, 1.30-2.44; P-value<0.001) were more likely to answer "yes" on question for depressive symptoms. In conclusion, low serum levels of 25(OH)D were associated with an increased risk for depression symptoms in Korean adults. In addition, several sociodemographic factors were related to the depressive symptoms. Our results provide insight into the relationships among vitamin D status, sociodemographic factors, and depression in the Korean population.

Vitamin D activates the Nrf2-Keap1 antioxidant pathway and ameliorates nephropathy in diabetic rats

BACKGROUND

Diabetic nephropathy is a major risk of end-stage kidney disease. Many complex factors relate to the progression of diabetic nephropathy. Using nonobese type 2 diabetes model rats, we confirmed that oxidative stress was a crucial factor. Because recent studies suggest that vitamin D could suppress oxidative stress, we explored whether the active vitamin D analog, maxacalcitol, could also attenuate oxidative stress and prevent the progression of diabetic nephropathy.

METHODS

Diabetic rats aged 20 weeks were divided into 3 groups and treated with insulin, maxacalcitol, and vehicle. At age 30 weeks, blood and urine analyses, renal histology, immunohistochemistry, real-time polymerase chain reaction, and western blot were performed.

RESULTS

Although maxacalcitol reduced albuminuria and mesangial matrix expansion, no significant differences were observed in blood pressure and creatinine clearance among the 3 treatment groups. Systemic and intrarenal oxidative stress was reduced by maxacalcitol therapy. Expressions of nuclear factor-κB and nicotinamide adenine dinucleotide phosphate oxidase in the kidney also decreased in the insulin-treated and maxacalcitol-treated groups but increased in the vehicle-alone group. In addition, the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) decreased and Kelch-like erythroid cell-derived protein with CNC homology (ECH)-associated protein 1 (Keap1) increased in the vehicle-treated group; however, these expressions were restored in the maxacalcitol- and insulin-treated groups.

CONCLUSIONS

It is suggested that maxacalcitol attenuates the progression of diabetic nephropathy by suppression of oxidative stress and amelioration of the Nrf2-Keap1 pathway in nonobese type 2 diabetes without significant changes in blood pressure and glomerular filtration rate.

Resistant starch: promise for improving human health

Ongoing research to develop digestion-resistant starch for human health promotion integrates the disciplines of starch chemistry, agronomy, analytical chemistry, food science, nutrition, pathology, and microbiology. The objectives of this research include identifying components of starch structure that confer digestion resistance, developing novel plants and starches, and modifying foods to incorporate these starches. Furthermore, recent and ongoing studies address the impact of digestion-resistant starches on the prevention and control of chronic human diseases, including diabetes, colon cancer, and obesity. This review provides a transdisciplinary overview of this field, including a description of types of resistant starches; factors in plants that affect digestion resistance; methods for starch analysis; challenges in developing food products with resistant starches; mammalian intestinal and gut bacterial metabolism; potential effects on gut microbiota; and impacts and mechanisms for the prevention and control of colon cancer, diabetes, and obesity. Although this has been an active area of research and considerable progress has been made, many questions regarding how to best use digestion-resistant starches in human diets for disease prevention must be answered before the full potential of resistant starches can be realized.

Defining a cutoff point for vitamin D deficiency based on insulin resistance in children

BACKGROUND

Vitamin D deficiency is a common worldwide problem. Low levels of serum 25-hydroxy vitamin D [25(OH)D], as a marker of vitamin D deficiency, have been linked to a wide field of health problems, including metabolic diseases such as insulin resistance, type 1 and type 2 DM. There is no universal definition for cutoff value of vitamin D deficiency and it seems that it varies in different populations.

OBJECTIVE

Most previous studies have used a start rise of PTH as a criteria to detect threshold of serum 25(OH)D, However, the aim of this study was to determine a cutoff point of serum 25(OH)D for vitamin D deficiency based on HOMA-IR.

MATERIALS AND METHODS

Two hundred and ninety seven healthy children (aged 7-11 years) were enrolled. Serum 25(OH)D and PTH were measured and HOMA-IR was calculated. The ROC curve was utilized to obtain a cutoff of vitamin D deficiency based on HOMA-IR.

RESULTS

25(OH)D concentrations were inversely correlated with HOMA-IR levels (Spearman's r=-0.14, p=0.016). Serum 25(OH)D cutoff point was 11.6ng/mL (29nmol/L) in relation with HOMA-IR >2.1. By using this cutoff value, the prevalence of vitamin D deficiency was 43.4% in this study population of healthy children.

CONCLUSION

We found that serum 25(OH)D levels are inversely associated with insulin resistance. These results suggest that in MetS patients it may benefit to determine cutoff value of 25(OH)D levels based on HOMA-IR.

Polymorphisms in GC and NADSYN1 Genes are associated with vitamin D status and metabolic profile in Non-diabetic adults

BACKGROUND

Our aim was to assess the associations between vitamin D (vitD) status, metabolic profile and polymorphisms in genes involved in the transport (Group-Component: GC) and the hydroxylation (NAD synthetase 1: NADSYN1) of 25 hydroxyvitamin D (25(OH)D) in non-diabetic individuals.

METHODS

We conducted a cross-sectional study with 323 individuals recruited from the Health Center of Guadeloupe, France. The rs2282679 T > G and rs2298849 T > C in GC and rs12785878 G > T in NADSYN1 were genotyped.

RESULTS

Mean age was 46(range 18-86) years. 57% of participants had vitD insufficiency, 8% had vitD deficiency, 61% were overweight and 58% had dyslipidemia. A higher frequency of overweight was noted in women carrying rs2298849T allele v CC carriers (71% v 50%; P = 0.035). The rs2282679G allele was associated with increased risks of vitD deficiency and vitD insufficiency (OR =3.53, P = 0.008, OR = 2.34, P = 0.02 respectively). The rs2298849 TT genotype was associated with vitD deficiency and overweight (OR =3.4, P = 0.004 and OR = 1.76, P = 0.04 respectively) and the rs12785878 GG genotype with vitD insufficiency and dyslipidemia (OR = 1.80, P = 0.01 and OR = 1.72, P = 0.03 respectively). Based on the number of risk alleles for rs2282679 and rs12785878 combined, a genotype score of 3 (vs. 0-1) was associated with a 5.5 ng/mL average reduction in serum 25(OH)D levels (P = 0.001).

CONCLUSIONS

The GC and NADSYN1 genes are associated with the vitamin D status and might contribute to dyslipidemia and overweight independently of 25(OH)D levels.