A systematic review on the efficacy of vitamin B supplementation on diabetic peripheral neuropathy.

CONTEXT: Diabetic peripheral neuropathy (DPN) is a common complication. OBJECTIVE: To re-evaluate the role of vitamin B supplementation on reducing the signs and symptoms of DPN. DATA SOURCES: Electronic databases such as PubMed, Cochrane Library, and Medline. DATA EXTRACTION: An Excel spreadsheet was used to report the extracted relevant data. DATA ANALYSIS: Fourteen randomized controlled trials were selected, comprising a pooled sample of 997 study subjects. The pooled odds ratio values were 3.1 (95%CI, 1.197-8.089) and 3.04 (95%CI, 1.556-5.937) for pain and dysesthesia outcomes, respectively. For the amplitude change in electromyography of the sensory sural nerve, the weighted difference from 2 studies was 0.37 (95%CI, 0.034-0.709) in favor of intervention. Peak latency changes were in favor of the intervention group. Two studies yielded a weighted difference of 0.571 (95%CI, 0.310-0.831) for the velocity outcome in favor of intervention. Unlike the fibular nerve, the electromyographic motor outcomes of the tibial nerve were in favor of vitamin B supplementation. CONCLUSION: Vitamin B supplementation could improve many symptoms and signs of DPN.

Is diabetic neuropathy associated with vitamin D status? A meta-analysis.

Several studies have been conducted to investigate the relation between 25-hydroxyvitamin D [25(OH)D] level and diabetic neuropathy (DN). However, there is still no clear conclusion due to differences in study design and cut-off values used in the published work, in addition to the absence of a comprehensive meta-analysis (MA) on the topic. The present systematic review and MA therefore aims at clarifying the association between vitamin D level and peripheral DN in patients with type 2 diabetes mellitus. Primary research studies that explored the association between 25(OH)D level and diabetic peripheral neuropathy in type 2 diabetes were located from Medline, EMBASE, Web of Science, Cochrane Library, CINHAL and Google Scholar. Twenty-six studies met the inclusion criteria with 6277 participants where 2218 were diabetic with DN, 2959 were diabetic without DN and 406 were healthy. Diabetic patients with DN showed significantly lower serum 25(OH)D compared with patients without DN (standardised mean difference (SMD) of -0·92 (95 % CI -1·18, -0·65, I2 = 93·3 %, P < 0·0001). The pooled OR value of vitamin D deficiency was higher in patients with DN, 1·84 (95 % CI 1·46, 2·33, P < 0·0001) and 2·87 (95 % CI 1·10, 7·52, P = 0·03) when using fixed-effects and random-effects models, respectively. Vitamin D deficiency has been found to be highly prevalent among diabetic patients with neuropathy. Since 25(OH)D has been implicated in glucose haemostasis and showed benefit in reducing neuropathy symptoms, its supplementation is warranted for this population of patients.

Effect of Vitamin D Supplementation on Inflammatory Markers in Non-Obese Lebanese Patients with Type 2 Diabetes: A Randomized Controlled Trial.

BACKGROUND: A low serum 25-hydroxyvitamin D (25(OH) D) concentration has been associated with a higher risk of type 2 diabetes mellitus (T2DM), especially in older people. Our aim in this randomized controlled trial was to evaluate the effect of vitamin D treatment on inflammatory markers in non-obese Lebanese patients with T2DM, living in Beirut, Lebanon. METHODS: Non-Obese patients with T2DM (n = 88), deficient/insufficient in vitamin D, were randomly assigned into one of two groups-a treatment group receiving 30,000 IU cholecalciferol/week for a period of six months, and a placebo group. Serum concentrations of TNF-α, high-sensitivity C-reactive protein (hs-CRP), and Interleukin-6 (IL-6) were the primary outcomes. A homeostatic model of insulin resistance (HOMA-IR) was assessed, in addition to serum concentrations of fasting blood glucose (FBG), HbA1C, (25(OH) D), and PTH. RESULTS: The vitamin D group showed higher blood levels of (25(OH) D) (p < 0.0001), and a significant reduction in hs-CRP and TNF-α concentrations (p < 0.0001) compared to placebo. The decrease perceived in IL-6 concentrations was not significant (p = 0.1). No significant changes were seen in FBG (p = 0.9) and HbA1c levels (p = 0.85). CONCLUSION: Six months of vitamin D supplementation led to a decrease in some inflammatory markers in patients with T2DM. Additional studies with a larger sample and a longer period are advised in this regard. This trial was registered at ClinicalTrial.gov; Identifier number: NCT03782805.

A systematic review on the efficacy of vitamin D supplementation on diabetic peripheral neuropathy.

BACKGROUND & AIMS: Vitamin D deficiency is known to be prevalent in patients with diabetes and in particular in those having symptoms of diabetic peripheral neuropathy (DN). Thus, it is worthy to investigate whether a supplementation of vitamin D would improve pain among those having diabetes and DN. METHODS: A systematic literature search was performed to identify studies that reported the impact of vitamin D supplementation on the signs and symptoms of DN. Random effect models were used to meta-analyze effect sizes. Quality assessment was also performed. RESULTS: Four studies including 364 patients met the inclusion criteria. Meta-analytical results were as follows: Serum Vitamin D level change of 1.39 (95% CI = 1.220 to 1.573, p = 0.008), HbA1c change of 0.134 (95% CI = -0.153 to 0.418, p = 0.3), McGill Pain Questionnaire score of 1.14 (95% CI = 1.222 to 1.672, p < 0.0001), all in favor of the vitamin D supplementation group. Non-meta-analytical results of all individual studies showed significant amelioration of pain scores. One study reported no significant change in nerve conduction study. Pain improvement was not correlated to baseline or change in serum vitamin D level. CONCLUSION: Vitamin D supplementation could be an added value in the treatment of painful peripheral diabetic neuropathy. Amelioration in pain might be related to the absolute value of vitamin D attained following supplementation. The findings of this review are promising and further research with large sample randomized trials is warranted.

Is there an association between vitamin D and diabetic foot disease? A meta-analysis.

It has been demonstrated that Vitamin D (25(OH)D) deficiency is associated with diabetes and with diabetic neuropathy. Some reports stated that vitamin D deficiency is also associated with diabetic foot ulcer and/or infection. Knowing the beneficial effect of vitamin D on wound healing, a quantitative evidence synthesis is needed to look for such association. Medline, Embase, Scopus, CINAHL, Cochrane Library, and Google Scholar were searched for from inception. The outcomes were set to be either the serum 25(OH)D level or the prevalence of patients with 25(OH)D with severe deficiency. Ten studies met the inclusion criteria with 1,644 patients; 817 diabetic patients with foot ulcers and 827 patients having diabetes without foot complications. The weighted mean differences was -0.93 (95% CI = -1.684 to -0.174, I2 = 97.8%, p = 0.01). The odds ratio of having severe vitamin D deficiency was 3.6 (95% CI = 2.940 to 4.415, I2 = 40.9%, p < 0.0001), in favor of the foot group. The quality of the included studies was found to be good to excellent. Diabetic foot complications are associated with significantly lower levels of vitamin D. Patients with diabetic ulcers or diabetic infection are at higher risk of bearing severe vitamin D deficiency. Knowing the beneficial effect of vitamin D on wound healing, it is likely that recognizing and supplementing with vitamin D could prevent or improve the outcomes of diabetic foot complications.