The Association of Vitamin D Status and Vitamin D Replacement Therapy with Glycemic Control, Serum Uric Acid Levels, and Microalbuminuria in Patients with Type 2 Diabetes and Chronic Kidney Disease

Association between 25 hydroxyvitamin D and serum uric acid level in the Chinese general population: a cross-sectional study

BACKGROUD

The relationship between serum uric acid (SUA) and 25-hydroxyvitamin D (25(OH)D) has been variably characterized in existing literature, with inconsistent results regarding its nature and implications in the Chinese population. This study aims to clarify this association, considering the potential impact of vitamin D levels on SUA.

METHODS

This cross-sectional study involved 7,086 individuals from the Second Affiliated Hospital of Zhejiang University School of Medicine, screened throughout 2020. We collected data on 25(OH)D, SUA, and other metabolic markers. Logistic regression models adjusted for confounding factors were utilized to analyze the relationships.

RESULTS

Our findings illustrate a statistically significant inverted U-shaped relationship between 25(OH)D and SUA. The identified threshold effect at 28.82 ng/ml is pivotal; with 25(OH)D levels below this point associated with an increased risk of hyperuricemia (odds ratio: 1.0146, p = 0.0148), and levels above it offering protective benefits (odds ratio: 0.9616, p = 0.0164).

CONCLUSIONS

Our findings confirm a nonlinear, inverted U-shaped correlation between 25(OH)D and SUA, emphasizing the importance of maintaining vitamin D levels within a specific range to effectively manage hyperuricemia. These results support the implementation of personalized vitamin D supplementation strategies to optimize metabolic health outcomes, highlighting the complex interplay between vitamin D status and uric acid levels.

The Inverted U-Shaped Association between Serum Vitamin D and Serum Uric Acid Status in Children and Adolescents: A Large Cross-Sectional and Longitudinal Analysis

BACKGROUND

Serum vitamin D is associated with hyperuricemia. However, previous studies have been controversial, with limited focus on children and adolescents.

OBJECTIVE

This study aimed to examine the cross-sectional and longitudinal associations between serum vitamin D and serum uric acid (SUA) levels in children and adolescents.

METHODS

The cross-sectional survey comprised 4777 participants aged 6 to 18 years, while the longitudinal survey involved 1641 participants aged 6 to 12 years, all derived from an ongoing cohort study in Shenzhen, China. Restricted cubic splines were used to visualize the dose-response relationship between vitamin D and SUA and the risk of higher SUA status. Two-segment generalized linear models (GLM) and logistic models were used to assess the association between vitamin D and SUA and higher SUA status, respectively. The longitudinal analysis used GLM.

RESULTS

We observed an inverted U-shaped relationship between vitamin D and SUA (p-overall < 0.0001, p-nonlinear = 0.0002), as well as the risk of higher SUA status (p-overall = 0.0054, p-nonlinear = 0.0015), with the vitamin D inflection point at 24.31 and 21.29 ng/mL, respectively. A 10 ng/mL increment in 25(OH)D3 levels, when below 20.92 ng/mL, was associated with a 68% rise in the risk of higher SUA status (OR: 1.68, 95%CI: 1.07-2.66). Conversely, when 25(OH)D3 levels were above or equal to 20.92 ng/mL, a 10 ng/mL increment was associated with a 45% reduction risk of higher SUA status (OR: 0.55, 95%CI: 0.36-0.84). Longitudinal analysis indicated that the annual change of SUA was from -4.80 (β, 95%CI: -10.74, 1.13) to -9.00 (β, 95%CI: -15.03, -2.99) and then to -6.77 (β, 95%CI: -12.83, -0.71, p for trend = 0.0212) μmol/L when increasing the quartile of vitamin D3.

CONCLUSIONS

An inverse U-shaped relationship was observed between vitamin D and SUA as well as the risk of higher SUA status. Sufficient vitamin D levels appear to play a preventative role against the age-related increase in SUA. Ensuring adequate vitamin D levels may be beneficial in improving uric acid metabolism.

Exploring the causal associations of micronutrients on urate levels and the risk of gout: A Mendelian randomization study

BACKGROUND & AIMS

Growing evidence has indicated a potential association between micronutrient levels, urate levels, and the risk of gout. However, the causal association underlying these associations still remains uncertain. Previous observational studies and randomized controlled trials investigating the association between micronutrients, urate levels, and the risk of gout have been limited in their scope and depth. The aim of this study was to utilize Mendelian randomization (MR) to investigate the causal associations between genetically predicted micronutrient levels, urate levels, and the risk of gout.

METHODS

In this study, we conducted a comprehensive examination of 10 specific micronutrients (vitamin B6, vitamin B12, vitamin C, vitamin D, folate, calcium, iron, copper, zinc, and selenium) as potential exposures. Two-sample MR analyses were performed to explore their causal associations with urate levels and the risk of gout. In these analyses, gout data were collected from the Global Biobank Meta-Analysis Initiative (N = 1,069,839, N cases = 30,549) and urate levels data from CKDGen Consortium (N = 288,649) by utilizing publicly available summary statistics from independent cohorts of European ancestry. We performed inverse-variance weighted MR analyses as main analyses, along with a range of sensitivity analyses, such as MR-Egger, weighted median, simple mode, weighted mode, Steiger filtering, MR-PRESSO, and Radial MR analysis, to ensure the robustness of our findings.

RESULTS

The results of our study indicate that there were negative associations between serum vitamin B12 and urate levels, as well as serum folate and the risk of gout. Specifically, we found a negative association between vitamin B12 levels and urate levels, with a β coefficient of -0.324 (95% CI -0.0581 to -0.0066, P = 0.0137) per one standard deviation (SD) increase. Similarly, a negative association was observed between folate levels and gout risk, with an odds ratio of 0.8044 (95% CI 0.6637 to 0.9750, P = 0.0265) per one SD increase. On the other hand, we identified positive associations between serum calcium levels and both urate levels and the risk of gout. Specifically, there was a positive association between serum calcium levels and urate levels (β coefficient: 0.0994, 95% CI 0.0519 to 0.1468, P = 4.11E-05) per one SD increase. Furthermore, a positive association was found between serum calcium levels and the risk of gout, with an odds ratio of 1.1479 (95% CI 1.0460 to 1.2598, P = 0.0036) per one SD increase. These findings were robust in extensive sensitivity analyses. By employing MR-PRESSO and Radial MR to eliminate outliers, the observed associations have been reinforced. No clear associations were found between the other micronutrients and the urate levels, as well as the risk of gout.

CONCLUSION

Our findings provided evidence that there were negative associations between serum vitamin B12 and urate levels, as well as serum folate and the risk of gout, while positive associations existed between the serum calcium levels and urate levels, as well as the risk of gout.

Serum 25-hydroxyvitamin D might be negatively associated with hyperuricemia in U.S. adults: an analysis of the National Health and Nutrition Examination Survey 2007-2014

PURPOSE

The results of previous studies on the relationship between serum 25-hydroxyvitamin D [25(OH)D] and hyperuricemia are controversial. We hypothesized that serum 25(OH)D concentrations of U.S. adults would negatively correlate with the risk of hyperuricemia.

METHOD

Data came from the National Health and Nutrition Examination Survey 2007-2014 were used, after excluding those who met at least one of the exclusion criteria, a total of 9096 male individuals and 9500 female individuals aged 18 years or older were included. Binary logistic regression analysis and restricted cubic spline with fully adjusted confounding factors were applied to evaluate the association between serum 25(OH)D and hyperuricemia. We further performed stratified analysis and sensitivity analysis to minimize the influence of gender, metabolic syndrome, obesity and renal dysfunction on the above association.

RESULTS

We found a negative correlation between serum 25(OH)D and hyperuricemia. In the binary logistic regression analysis, compared with the highest serum 25(OH)D quartile [Q4: 25(OH)D > 77.10 nmol/L] group, the odds ratios (95% confidence intervals) in the lowest quartile [Q1: 25(OH)D ≤ 43.20 nmol/L] was 1.46 (1.22-1.75) in the fully adjusted model. Restricted cubic spline analysis showed L-shaped and non-linear relationships between 25(OH)D and hyperuricemia. In sensitivity analysis, after restricting to participants without significant renal dysfunction and obesity, the above association remained significant. After restricting to participants who were diagnosed as metabolic syndrome, above association remained significant in the fully adjusted model. In stratified analysis by gender, the association remained significant among males and females.

CONCLUSIONS

Serum 25(OH)D might be inversely associated with hyperuricemia in general U.S. adults. From our study, for people with unexplained hyperuricemia, screening for serum Vitamin D concentration might be necessary.

Health implication of vitamin D on the cardiovascular and the renal system

Vitamin D regulates the calcium and phosphorus balance in the body. The activated form of vitamin D (1 α,25-dihydroxyvitamin D) binds to vitamin D receptor which regulates genes that control cell proliferation, differentiation and apoptosis. In the cardiovascular system, the vitamin D receptor is present in cardiomyocytes and the arterial wall. A clear correlation between vitamin D level and cardiovascular diseases is established. Vitamin D deficiency affects the renin-angiotensin system leading to ventricular hypertrophy and eventually to stroke. While clinical trials highlighted the positive effects of vitamin D supplements on cardiovascular disease these still need to be confirmed. This review outlines the association between vitamin D and cardiovascular and renal disease summarising the experimental data of selective cardiovascular disorders.

Cystatin C, Vitamin D and Thyroid Function Test Profile in Chronic Kidney Disease Patients

BACKGROUND

The progression of chronic kidney disease (CKD) is concomitant with complications, including thyroid dysfunction, dyslipidemia and cardiovascular diseases. The aim of this study is to determine serum cystatin C levels, and the prevalence of vitamin D deficiency and thyroid dysfunction in CKD patients.

METHODS

A cross-sectional study was conducted involving 140 CKD patients (stages 1-5) that were referred to a renal clinic. Demographic data was collected and thyroid function tests, serum 25-OH-vitamin D, cystatin C levels, and routine biochemistry tests were determined using cobas 6000 analyzer.

RESULTS

129 (92.1%) of CKD patients had elevated serum cystatin C levels and there was a stepwise increase from stage 1-5. Overt hypothyroidism was present in one patient and nine had subclinical hypothyroidism. There was a stepwise reduction in serum 25-OH-vitamin D levels from stage 2-5, 31 (22.1%) had vitamin D insufficiency and 31 (22.1%) presented with deficiency.

CONCLUSIONS

25-OH-vitamin D deficiency and thyroid disorders are exhibited in chronic kidney disease patients and the severity of the former rises with disease progression, as indicated by elevated cystatin C levels. Routine screening and timely intervention is recommended so as to reduce the risk of cardiovascular diseases.

Association Between Vitamin D and Uric Acid in Adults: A Systematic Review and Meta-Analysis

Association between vitamin D and uric acid is complex and might be bidirectional. Our study aimed to determine the bidirectional association between vitamin D and uric acid in adults. Using MEDLINE via PubMed and Scopus, we systematically searched for observational or interventional studies in adults, which assessed the association between serum vitamin D and serum uric acid, extracted the data, and conducted analysis by direct and network meta-analysis. The present review included 32 studies, of which 21 had vitamin D as outcome and 11 had uric acid as outcome. Meta-analysis showed a significant pooled beta coefficient of serum uric acid level on serum 25(OH)D level from 3 studies of 0.512 (95% confidence interval: 0.199, 0.825) and a significant pooled odds ratio between vitamin D deficiency and hyperuricemia of 1.496 (1.141, 1.963). The pooled mean difference of serum 25(OH)D between groups with hyperuricemia and normouricemia was non-significant at 0.138 (-0.430, 0.707) ng/ml, and the pooled mean difference of serum uric acid between categories of 25(OH)D were also non-significant at 0.072 (-0.153, 0.298) mg/dl between deficiency and normal, 0.038 (-0.216, 0.292) mg/dl between insufficiency and normal, and 0.034 (-0.216, 0.283) mg/dl between deficiency and insufficiency. In conclusion, increasing serum uric acid might be associated with increasing 25(OH)D level, while vitamin D deficiency is associated with hyperuricemia. These reverse relationships should be further evaluated in a longitudinal study.

Management of Type 2 Diabetes: Current Strategies, Unfocussed Aspects, Challenges, and Alternatives

Type 2 diabetes mellitus (T2DM) accounts for >90% of the cases of diabetes in adults. Resistance to insulin action is the major cause that leads to chronic hyperglycemia in diabetic patients. T2DM is the consequence of activation of multiple pathways and factors involved in insulin resistance and β-cell dysfunction. Also, the etiology of T2DM involves the complex interplay between genetics and environmental factors. This interplay can be governed efficiently by lifestyle modifications to achieve better management of diabetes. The present review aims at discussing the major factors involved in the development of T2DM that remain unfocussed during the anti-diabetic therapy. The review also focuses on lifestyle modifications that are warranted for the successful management of T2DM. In addition, it attempts to explain flaws in current strategies to combat diabetes. The employability of phytoconstituents as multitargeting molecules and their potential use as effective therapeutic adjuvants to first line hypoglycemic agents to prevent side effects caused by the synthetic drugs are also discussed.

Lower serum 25-hydroxyvitamin D levels are associated with impaired glomerular filtration rate in type 2 diabetes patients

BACKGROUND

25-Hydroxyvitamin D [25(OH)D] deficiency has been implicated as a possible risk factor for the onset and progression of diabetes kidney disease (DKD). The aim of this study was to evaluate the interaction between levels of 25(OH)D and DKD in type 2 diabetes mellitus (DM) patients.

METHODS

Cross-sectional design, outpatient type 2 DM. Glomerular filtration rate (GFR) was measured by 51Cr-EDTA and estimated by Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI), urinary albumin excretion (UAE) by immunoturbidimetry, and 25(OH)D by chemiluminescence. Receiver operating characteristic (ROC) curve analysis and generalized linear model (Poisson robust regression estimator) were used to assess the interaction between 25(OH)D levels and renal function.

RESULTS

A total of 114 type 2 DM patients aged 60 ± 10 years, 49 males (43%), DM duration 22 ± 10 years, with GFR > 60 ml/min/1.73 m2 were evaluated. Patients with GFRs 60-90 (n = 50) had significantly lower 25(OH)D levels than individuals with GFRs > 90 ml/min/1.73 m2 (n = 64), respectively 40 ± 20 versus 48 ± 20 nmol/l, p = 0.027. This difference was more pronounced for older individuals (39 ± 20 versus 54 ± 23 nmol/l, respectively), and Poisson robust regression disclosed that lower 25(OH)D [Poisson regression (PR) = 0.989, confidence interval (CI): 0.978-0.999, p = 0.034], and advanced age (PR = 1.050, CI: 1.007-1.096, p = 0.023) were significantly associated with the lower GFR category, adjusted for seasons. ROC curve analysis showed that the cutoff point of 25(OH)D of 41 nmol/l was associated with lower GFR [area under the curve (AUC) = 0.694, p = 0.009]. CKD-EPI estimated GFR (eGFR) was not associated with 25(OH)D in any analysis. There was no difference in 25(OH)D levels between patients with elevated UAE as compared with normoalbuminuric ones (44 ± 21 versus 46 ± 19 nmol/l, p = 0.587).

CONCLUSION

Lower levels of 25(OH)D are associated with decreased GFR in patients with type 2 DM, especially in older patients, with no evidence of interaction with UAE levels.

Association between serum vitamin D and uric acid in the eastern Chinese population: a population-based cross-sectional study

BACKGROUND

Uric acid (UA) is the end product of purine metabolism, which is thought to be related to many human diseases, such as nephrolithiasis, gout, cardiovascular disease (CVD), type 2 diabetes mellitus, metabolic syndrome. However, the relationship between serum UA (SUA) and 25(OH) D is still unclear in the eastern Chinese population.

METHODS

We did a population-based observational investigation, which included 12,770 residents living in eastern China. Ultimately, data from 9220 subjects were analyzed. Serum 25(OH) D, SUA, fasting plasma glucose (FPG), fasting insulin, HbA1c and other metabolic parameters were tested. Waist circumference (WC), weight and height were also measured. Questionnaires were collected from these subjects for information on smoking and drinking status.

RESULTS

We enrolled 9220 Chinese adults, including 3681 males (age 55.57 ± 13.23 years) and 5539 females (age 54.31 ± 12.83 years). The levels of SUA were 352.07 ± 79.25 nmol/L and 269.29 ± 64.68 nmol/L in males and females, respectively. The proportion of adults with hyperuricemia (HUA) was 12.26% in the total population. Levels of SUA were positively associated with 25(OH) D, and the incidence of HUA increased 9.4% for every 10 nmol/L increase in 25(OH) D (P < 0.001).

CONCLUSIONS

SUA was positively associated with 25(OH) D in the eastern Chinese population. Higher levels of serum 25(OH) D may be a potential predictor of HUA.

No effect of vitamin D supplementation on metabolic parameters but on lipids in patients with type 2 diabetes and chronic kidney disease

Background/Aims: Trials on the effects of cholecalciferol supplementation in type 2 diabetes with chronic kidney disease patients were underexplored. Therefore, the aim of this study was to investigate the effects of two different doses of vitamin D supplementation on serum 25-hydroxyvitamin D [25(OH)D] concentrations and metabolic parameters in vitamin D-deficient Korean diabetes patients with chronic kidney disease. Methods: 92 patients completed this study: the placebo group (A, n = 33), the oral cholecalciferol 1,000 IU/day group (B, n = 34), or the single 200,000 IU injection group (C, n = 25, equivalent to 2,000 IU/day). 52% of the patients had less than 60 mL/min/1.73m² of glomerular filtration rates. Laboratory test and pulse wave velocity were performed before and after supplementation. Results: After 12 weeks, serum 25(OH)D concentrations of the patients who received vitamin D supplementation were significantly increased (A, -2.4 ± 1.2 ng/mL vs. B, 10.7 ± 1.2 ng/mL vs. C, 14.6 ± 1.7 ng/mL; p < 0.001). In addition, the lipid profiles in the vitamin D injection group (C) showed a significant decrease in triglyceride and a rise in HDL cholesterol. However, the other parameters showed no differences. Conclusions: Our data indicated that two different doses and routes of vitamin D administration significantly and safely increased serum 25(OH)D concentrations in vitamin D-deficient diabetes patients with comorbid chronic kidney disease. In the group that received the higher vitamin D dose, the lipid profiles showed significant improvement, but there were no beneficial effects on other metabolic parameters.

Type 2 Diabetes Mellitus, Insulin Resistance, and Vitamin D

PURPOSE OF REVIEW

There is a growing, largely inconsistent, literature on the role of vitamin D in association with type 2 diabetes, insulin resistance/insulin secretion, glycemic indices, and complications of type 2 diabetes. Pathophysiologic, bystander, preventive, and treatment roles of vitamin D have all been proposed. In this focused review, we attempt to organize and clarify our current information in this area.

RECENT FINDINGS

Clinical study interpretation is difficult because of variability in dosage, dosage form, study duration, and populations studied, as well as recently reported normal human polymorphisms in vitamin D synthesis and catabolism, vitamin D-binding protein, and vitamin D receptors in addition to a host of potential epigenetic confounders. Low vitamin D status appears to be associated with type 2 diabetes and most other insulin resistance disorders reported to date. The extraskeletal benefits of supplementation/repletion in these disorders in our species, with a few highlighted exceptions, remain to be established. This focused review attempts to summarize our current knowledge in this burgeoning area through a review of key meta-analyses, observational studies, randomized control trials, and Mendelian randomization studies and will hopefully serve as a guide to indicate future research directions and current best practice.

Urine albumin and serum uric acid are important determinants of serum 25 hydroxyvitamin D level in pre-dialysis chronic kidney disease patients

Low serum 25 hydroxyvitamin D (25 OH D) is common among chronic kidney disease (CKD) patients. This cross-sectional study is looking for the different factors associated with serum 25 OH D among pre-dialysis CKD. 1624 adult stage 3–5 CKD patients were studied beside 200 normal control subjects. All candidates were tested for body mass index (BMI), estimated glomerular filtration rate (eGFR), calcium (Ca), phosphorus (P), parathormone (PTH), 25 OH D, albumin, and uric acid (UA), and urine albumin/creatinine ratio (ACR). Multivariate linear regression analysis was done to determine predictors of 25 OH D. 98.6% of CKD patients have inadequate level of 25 OH D vs 48% of normal subjects. Serum 25 OH D was significantly lower in CKD patients (mean ± S.D = 16.54 ± 5.8 vs 37.79 ± 3.58 ng/mL for CKD vs control group respectively, p < .001). Serum level of 25 OH D has significant positive correlation with Ca (r = 0.337, p < .001), and significant negative correlation with P, PTH, UA, and ACR (r = −0.440, −0. 679, −0.724, and −0.781respectively, p < .001 in all). The independent predictors of 25 OH D were Ca, P, UA, PTH, and ACR (R square = 0.7, β = −0.087, −0.226, −0.313, −0.253, and −0.33 respectively, p < .001 in all). In conclusion, pre-dialysis CKD patients frequently suffer low 25 OH D. Among the different abnormalities related to CKD, urine albumin excretion rate and UA are the most important predictors of 25 OH D in these patients.

Role of Vitamin D Status in Diabetic Patients with Renal Disease

Diabetes mellitus (DM) poses a major public health problem worldwide, with ever-increasing incidence and prevalence in recent years. The Institute for Alternative Futures (IAF) expects that the total number of people with type 1 and type 2 DM in the United States will increase by 54%, from 19,629,000 to 54,913,000 people, between 2015 and 2030. Diabetic Nephropathy (DN) affects about one-third of patients with DM and currently ranks as the first cause of end-stage kidney disease in the Western world. The complexity of interactions of Vitamin D is directly related with progressive long-term changes implicated in the worsening of renal function. These changes result in a dysregulation of the vitamin D-dependent pathways. Various studies demonstrated a pivotal role of Vitamin D supplementation in regression of albuminuria and glomerulosclerosis, contrasting the increase of glomerular basement membrane thickening and podocyte effacement, with better renal and cardiovascular outcomes. The homeostasis and regulation of the nephron's function are absolutely dependent from the cross-talk between endothelium and podocytes. Even if growing evidence proves that vitamin D may have antiproteinuric, anti-inflammatory and renoprotective effects in patients with DN, it is still worth investigating these aspects with both more in vitro studies and randomized controlled trials in larger patient series and with adequate follow-up to confirm the effects of long-term vitamin D analogue supplementation in DN and to evaluate the effectiveness of this therapy and the appropriate dosage.

Vitamin D deficiency and glycemic control among patients with type 2 diabetes mellitus in Jazan City, Saudi Arabia

Background: The prevalence of vitamin D deficiency (VDD) is predicted to be high in patients with type 2 diabetes mellitus (T2DM), but the exact figure is not known in Jazan, Saudi Arabia. Emerging data suggests that VDD plays a role in glycemic control. The aim of this study was to measure the prevalence of VDD among T2DM patients and to investigate its association with patients' characteristics and glycemic control in Jazan. Methods: This is an analytical cross-sectional study which recruited 309 patients with T2DM randomly from primary health care centers in Jazan. Logistic regression analysis was conducted to determine the VDD predictors and to examine the association of VDD and glycemic control. Results: The VDD prevalence was found to be 60.8% in patients with T2DM. Age, gender, diabetic retinopathy (DR), dyslipidemia, glycemic control, and obesity were significantly associated with VDD, and all except obesity were independent predictors of VDD. There was a significant negative correlation between 25-hydroxyvitamin D and HbA1c. VDD was a significant independent predictor of poor glycemic control after adjustment for hypertension, DR, diabetic neuropathy, type of diabetes medication, diabetes duration, and education level. Conclusion: In this Saudi Arabian population, VDD is highly prevalent in people with T2DM and is associated with poor glycemic control. Health education targeting patients with T2DM and national strategies regarding vitamin D fortification are needed to prevent VDD in Saudi Arabia. Earlier VDD diagnosis by health care providers may help to improve the outcome for patients with T2DM. Establishing the causal association between VDD and glycemic control and clarifying the biological role of vitamin D in T2DM are important aims for future studies.

Urinary Uromodulin/Creatinine Ratio as a Potential Clinical Biomarker for Chronic Kidney Disease Patients with Gout: A Pilot Study

OBJECTIVE

Recent studies have reported that reduced excretion of urinary uromodulin is associated with renal tubular function and risks of progressive kidney disease. Gouty nephropathy is usually seen in patients with gout. Patients with chronic gouty nephropathy are characterized by the deposition of monosodium urate crystals primarily involving the collecting ducts in the medulla. We postulated that this correlation may be specific to gout and may serve as a useful biomarker for chronic kidney disease (CKD).

MATERIALS AND METHODS

A total of 114 Taiwanese patients diagnosed with gout (n = 72), CKD (n = 26), or healthy volunteers (n = 16) were prospectively enrolled for this study from the Rheumatology and Nephrology Outpatient Clinics of our institution. We obtained urine and blood samples on patient visits to the outpatient clinics. Demographic data were obtained from medical records.

RESULTS

In patients with gout, the spot urinary uromodulin/creatinine ratio (uUMCR; mg/g) in patients with CKD was significantly lower than that in those without CKD (CKD group: 2.2; non-CKD group: 5.6, p = 0.005). Multivariate analysis revealed that patients with CKD and gout had a lower uUMCR than those with gout alone (p = 0.028). A significant association was not observed in our non-gout cohort.

CONCLUSION

The association of decreased uUMCR with CKD status was identified only in patients with gout in the present study. We believe that uUMCR might serve as an indicator of differential CKD in patients with gout.

Effect of Treating Vitamin D Deficiency in Uncontrolled Type 2 Diabetes: A Randomized, Placebo-Controlled Study

BACKGROUND

Literature increasingly supports the inverse relationship of vitamin D (VitD) level and type 2 diabetes (T2DM). Proposed protective mechanisms of VitD include its anti-inflammatory effects, increased insulin secretion via pancreatic β-cell stimulation, and downregulation of parathyroid hormone levels. Interventional studies show mixed results of VitD therapy in prediabetic patients with VitD deficiency or diabetic patients with normal VitD levels.

STUDY QUESTION

Does high-dose VitD replacement improve glycemic control and microalbuminuria (MAU) in uncontrolled T2DM and concurrent VitD deficiency?

STUDY DESIGN

This placebo-controlled, double-blinded study randomized 30 subjects aged 30-65 years with an elevated HbA1c level of 7.5%-10% and a low total 25-hydroxyvitamin-D value of <20 ng/mL to either placebo (n = 16) or ergocalciferol 50,000 IU (n = 14) once weekly for 8 weeks then once monthly for 4 months.

MEASURES AND OUTCOMES

Primary outcome was difference in HbA1c from baseline to month 6 between the VitD-intervention group and the placebo-controlled group. Secondary end points were differences in total 25-hydroxyvitamin-D and MAU. Paired t tests and linear mixed-effects models were used for statistical analysis.

RESULTS

No significant differences were seen in HbA1c or MAU between baseline versus postintervention visits within the placebo group (HbA1c: 8.4% ± 0.2 vs. 8.1% ± 0.3, P = 0.088; MAU: 94.1 mg/g ± 43.9 vs. 45.9 mg/g ± 20.2, P = 0.152) and the intervention group (HbA1c: 8.8% ± 0.3 vs. 8.7% ± 0.4, P = 0.692; MAU: 167.8 mg/g ± 70.1 vs. 108.5 mg/g ± 39.9, P = 0.356). The difference between placebo-slope and intervention-slope was nonsignificant for MAU (β = -0.1 mg/g ± 0.4, P = 0.835) but was significant for total 25-hydroxyvitamin-D (β = 11.7 ng/mL ± 2.5, P ≤ 0.001). Greater HbA1c reduction occurred unexpectedly in the placebo group ((Equation is included in full-text article.)= -0.4% ± 0.2) than in the intervention group ((Equation is included in full-text article.)= -0.2% ± 0.4), although the difference in slopes was not significant (β = 0.2% ± 0.4, P = 0.640).

CONCLUSIONS

Our proof-of-concept study found no benefit of high-dose VitD therapy in glycemic control and MAU in uncontrolled T2DM and VitD deficiency. Post hoc analyses raise concerns for high-dose VitD therapy to delay glycemic improvement. Large-scale interventional trials are much needed in this patient population to substantiate our findings and elucidate VitD's mechanisms on glucose metabolism.

The Relationship between Vitamin D and Type 2 Diabetes Is Intriguing: Glimpses from the Spect-China Study

OBJECTIVE

Vitamin D is a multifunctional vitamin for our body. Type 2 diabetes mellitus (T2DM) is a common metabolic disease. Whether T2DM affects the serum 25(OH)D level has not been reported. The objective of this study was to reveal the extent to which vitamin D is present in the population in East China and to explore the relationship between serum 25(OH)D and T2DM.

METHODS

The cohort was selected based on a large investigation named Survey on Prevalence in East China including 12,702 participants aged 21-92 years old. All the participants completed the questionnaire and went through a physical examination. Fasting blood samples were collected to test serum 25(OH)D and other metabolism-related indicators. AVONA was used to test the significance of differences among groups. Multinomial logistic regression was used to assess the association of T2DM with serum 25(OH)D level.

RESULTS

The overall percentage of vitamin D deficiency was 80.55% (male 74.1%, female 85.0%). Men with lower serum 25(OH)D level had high value in homeostasis model assessment of insulin resistance and HbA1c. The serum 25(OH)D level of those who were diagnosed with T2DM was higher than that in non-diabetics. The serum 25(OH)D level of pre-diabetes was the highest. T2DM patients trended to have higher serum 25(OH)D levels.

CONCLUSION

Vitamin D deficiency is common among the people in East-China. T2DM patients had higher levels of serum 25(OH)D. The relationship between vitamin D and T2DM is intriguing. It seemed that vitamin D was either irrelevant directly to T2DM or resisted in T2DM patients.

Dietary Whole Egg Consumption Attenuates Body Weight Gain and Is More Effective than Supplemental Cholecalciferol in Maintaining Vitamin D Balance in Type 2 Diabetic Rats

Background: Type 2 diabetes (T2D) is characterized by vitamin D insufficiency owing to excessive urinary loss of 25-hydroxycholecalciferol [25(OH)D]. We previously reported that a diet containing dried whole egg, a rich source of vitamin D, was effective at maintaining circulating 25(OH)D concentrations in rats with T2D. Furthermore, whole egg consumption reduced body weight gain in rats with T2D.Objective: This study was conducted to compare whole egg consumption with supplemental cholecalciferol with respect to vitamin D balance, weight gain, and body composition in rats with T2D.Methods: Male Zucker diabetic fatty (ZDF) rats (n = 24) and their lean controls (n = 24) were obtained at 5 wk of age and randomly assigned to 3 treatment groups: a casein-based diet (CAS), a dried whole egg-based diet (WE), or a casein-based diet containing supplemental cholecalciferol (CAS+D) at the same amount of cholecalciferol provided by WE (37.6 μg/kg diet). Rats were fed their respective diets for 8 wk. Weight gain and food intake were measured daily, circulating 25(OH)D concentrations were measured by ELISA, and body composition was analyzed by dual X-ray absorptiometry.Results: Weight gain and percentage of body fat were reduced by ∼20% and 11%, respectively, in ZDF rats fed WE compared with ZDF rats fed CAS or CAS+D. ZDF rats fed CAS had 21% lower serum 25(OH)D concentrations than lean rats fed CAS. In ZDF rats, WE consumption increased serum 25(OH)D concentrations 130% compared with CAS, whereas consumption of CAS+D increased serum 25(OH)D concentrations 35% compared with CAS.Conclusions: Our data suggest that dietary consumption of whole eggs is more effective than supplemental cholecalciferol in maintaining circulating 25(OH)D concentrations in rats with T2D. Moreover, whole egg consumption attenuated weight gain and reduced percentage of body fat in ZDF rats. These data may support new dietary recommendations targeting the prevention of vitamin D insufficiency in T2D.