Significant independent predictors of vitamin d deficiency in inpatients and outpatients of a nephrology unit

Relationship of Vitamin-D Deficiency with Kidney Disease in Patients with Type-2 Diabetes Mellitus (T2DM) in the Makkah Region: A Cross-Sectional Study

Aim

Vitamin D deficiency is linked with type 2 diabetes mellitus (T2DM) and the occurrence of complications in patients with type 2 diabetes mellitus. None of the studies have focused on the association between vitamin D levels in patients with type 2 diabetes mellitus and diabetic nephropathy (DN) in the Makkah region, Saudi Arabia. Hence, the purpose of this study is to investigate the relationship of vitamin D with kidney disease in patients with T2DM in the Makkah region, of Saudi Arabia.

Materials and Methods

This descriptive cross-sectional study was conducted at different hospitals in the Makkah region on T2DM patients from 2021 to 2022. In total, 328 patients with confirmed diabetes were enrolled in this study. T2DM patients over the aged>18 to 92 years were included in the study. General laboratory characteristics of the study population were measured, including fasting blood sugar, HbA1C (Glycated hemoglobin), vitamin D, kidney function (BUN-Blood urea nitrogen and creatinine), and lipid profiles (cholesterol, triglycerides, LDL-Low density lipoprotein, and HDL-High density lipoprotein).

Results

46.6% (n=153) of participants had normal serum vitamin D levels. Insufficient and deficient serum vitamin D level were observed in 43.9% (n=144) and 9.5% (n=31) of participants, respectively. Of the participants, 25.9% (n=85) had good glycemic control (<7.0%). Moderate and poor glycemic control were observed in 39.9% (n=131) and 34.1% (n=112) of the participants, respectively. A significant negative correlation (p<0.5) was found between vitamin D levels and kidney function test results (blood urea nitrogen and serum creatinine levels). An inverse relationship was observed between HbA1c levels and vitamin D deficiency.

Conclusion

Nephropathy is more likely to develop in people with type 2 diabetes mellitus and vitamin D deficiency.

Analytical, experimental and clinical aspects of total 25-hydroxyvitamin D measurement by two ligand assays are differentially biased by disease-related factors

BACKGROUND

Pathological concentrations of plasma proteins may confound the results of binding assays. We compared two routinely used total 25-hydroxyvitamin D [t-25(OH)D] methods: a chemiluminescence-immuno-(CLIA) and an electro-chemiluminescence-protein-binding-(ECLPBA) assay.

METHODS

Two sub-studies were performed: 1) In an "in vitro" study, exogenous albumin was added to pools of patients' sera with low albumin levels; and 2) In "ex vivo" studies of Cohort_1: sera of hospitalized patients with low albumin levels, and of healthy controls; and of Cohort_2: outpatients with chronic kidney disease in pre-dialysis stage, or on peritoneal dialysis and hemodialysis were investigated by the routine and LC_MS/MS methods.

RESULTS

When increasing albumin concentrations were "in vitro" added, t-25(OH)D levels were overestimated by ECLPBA, and underestimated by CLIA. In patients' sera, positive correlations were detected between t-25(OH)D-vitamin D binding protein (DBP) values by both routine methods, and between t-25(OH)D-albumin values by all three methods. Much higher t-25(OH)D was measured by LC_MS/MS in all subgroups. When altering albumin levels with constant DBP concentration, the "in vitro" experiment revealed a higher sensitivity of ECLPBA. The "ex vivo" measurements demonstrated clinically relevant differences between the routine methods.

CONCLUSION

Both routine methods are dependent of the matrix effect in hospitalized patients, which is predicted by the DBP/Albumin ratios. In hemodialysis, ECLPBA is recommended because its outcomes differ less from those of LC_MS/MS. The results of LC_MS/MS are reliable, but not routinely available. A guidance would be valuable on how levels measured by the binding methods differ from those by LC-MS/MS in various clinical conditions.

The Role of Vitamin D in the Relationship Between Gender and Deep Vein Thrombosis Among Stroke Patients

Introduction: Accumulating evidence had demonstrated that females had a higher risk of deep vein thrombosis (DVT) than males, but the mechanism was still unknown. Vitamin D was found to play an essential role in DVT, and gender may influence the serum vitamin D levels. This study aimed to explore whether vitamin D played a role in the gender difference in DVT.

Materials and Methods: A total of 444 patients with acute stroke were recruited, which were divided into the DVT group (n = 222) and the non-DVT group (n = 222). Serum vitamin D levels were measured after admission and were split into three categories, including deficiency (<50 nmol/L), insufficiency (52.5–72.5 nmol/L), and sufficiency (more than 75 nmol/L). Hierarchical regression analysis was adopted to analyze the relationship between gender and DVT, controlling the confounding factors.

Results: Females showed a higher proportion of DVT than males (60.7 vs. 42.5%, p < 0.001), and lower serum vitamin D levels than males (53.44 ± 16.45 vs. 69.43 ± 23.14, p < 0.001). Moreover, serum vitamin D levels were lower in the DVT group than in the non-DVT group (59.44 ± 19.61 vs. 66.24 ± 23.86, p < 0.001). Besides, the DVT group showed a lower proportion of vitamin D sufficiency than the non-DVT group (21.2 vs. 32.9%, p < 0.05). Hierarchical regression analysis showed that females had 2.083-fold (p < 0.001, unadjusted model) and 1.413-fold (p = 0.155, adjusted model) risk to develop DVT. In addition, the sufficiency status of vitamin D showed an independent protective effect on DVT (unadjusted model OR, 0.504, p = 0.004; adjusted model OR, 0.686, p = 0.011).

Conclusion: Females had a higher risk of DVT than males, and vitamin D may play an essential role in this relationship. Further studies are needed to explore whether vitamin D supplementation could reduce DVT risk in stroke patients, especially females.

The potential role of vitamin D supplementation as a gut microbiota modifier in healthy individuals

Vitamin D deficiency affects approximately 80% of individuals in some countries and has been linked with gut dysbiosis and inflammation. While the benefits of vitamin D supplementation on the gut microbiota have been studied in patients with chronic diseases, its effects on the microbiota of otherwise healthy individuals is unclear. Moreover, whether effects on the microbiota can explain some of the marked inter-individual variation in responsiveness to vitamin D supplementation is unknown. Here, we administered vitamin D to 80 otherwise healthy vitamin D-deficient women, measuring serum 25(OH) D levels in blood and characterizing their gut microbiota pre- and post- supplementation using 16S rRNA gene sequencing. Vitamin D supplementation significantly increased gut microbial diversity. Specifically, the Bacteroidetes to Firmicutes ratio increased, along with the abundance of the health-promoting probiotic taxa Akkermansia and Bifidobacterium. Significant variations in the two-dominant genera, Bacteroides and Prevotella, indicated a variation in enterotypes following supplementation. Comparing supplementation responders and non-responders we found more pronounced changes in abundance of major phyla in responders, and a significant decrease in Bacteroides acidifaciens in non-responders. Altogether, our study highlights the positive impact of vitamin D supplementation on the gut microbiota and the potential for the microbial gut signature to affect vitamin D response.

Sex, Residence and Fish Intake Predict Vitamin D Status in Chinese Centenarians

OBJECTIVES

This study aims to investigate the prevalence of vitamin D deficiency in Chinese centenarians and to identify the factors associated with vitamin D deficiency.

DESIGN

Cross-sectional population-based study.

SETTING

Hainan province in the south of China.

PARTICIPANTS

943 subjects aged 100 years old and older.

METHODS

Details on sociodemographics and lifestyle characteristics were collected using a structured questionnaire. Anthropometrics and blood samples were obtained. Vitamin D deficiency was defined as serum 25-hydroxyvitamin D concentration < 20ng/mL (50nmol/L).

RESULTS

The overall prevalence of vitamin D deficiency among these 943 centenarians was 39.9% (376 subjects) and the mean serum vitamin D concentrations were 22.7±9.5 (ng/mL). Female centenarians had higher prevalence of vitamin D deficiency than male (44.0% vs. 21.7%, P <0.001). Multivariate logistic regression analyses showed that being female, urban residency, lower body mass index, higher serum parathyroid hormone levels, no fish consumption, and less sun exposure time were all significant and independent determinants of vitamin D deficiency. No significant associations of vitamin D deficiency with ethnic, education, geographic location, tea drinking, alcohol use, or smoking were found in this study.

CONCLUSION

Vitamin D deficiency was common in Chinese centenarians, especially in women. Given that vitamin D deficiency is linked to numerous adverse health outcomes, dietary, outdoor activities and other intervention measures are needed to correct vitamin D deficiency in this population.

Vitamin D status among patients visiting a tertiary care center in Riyadh, Saudi Arabia: a retrospective review of 3475 cases

BACKGROUND

Vitamin D deficiency has been implicated in several chronic, non-communicable diseases independent of its conventional role in bone and calcium homeostasis. In this retrospective study, we determined the prevalence of vitamin D deficiency and its association to several cardiometabolic indices among patients visiting King Abdulaziz Medical City (KAMC), a tertiary hospital in Riyadh, Saudi Arabia.

METHODS

A total of 3475 charts of out-patient subjects who visited KAMC from September 2009 until December 2010 were reviewed and included. Variables of interest included measurements of vitamin D status, glycemic and renal profile, as well as trace elements (calcium and phosphorous).

RESULTS

The over-all prevalence of vitamin D deficiency in the cohort studied was 78.1% in females and 72.4% in males. 25(OH) vitamin D was significantly associated with increasing age and weight (p-values < 0.0001 and 0.005, respectively). It was also positively associated with albumin, calcium and phosphorous (p-values < 0.0001, < 0.0001 and 0.0007, respectively) and negatively associated with alkaline phosphatase as well as circulating levels of PTH (p-values 0.0002 and 0.0007, respectively).

CONCLUSION

In conclusion, vitamin D deficiency is overwhelmingly common among patients seen at KAMC regardless of the medical condition, and it is significantly associated with increasing age, weight and markers of calcium homeostasis. Findings of the present study further stress the spotlight on vitamin D deficiency epidemic in the country and region in general.