- Letter to the Editor
- Open Access
Comment to “Diabetic peripheral neuropathy: the potential role of vitamin D deficiency” by Oraby et al.
The Egyptian Journal of Neurology, Psychiatry and Neurosurgery volume 55, Article number: 27 (2019)
To the Editor,
We read with great interest the article by Oraby and colleagues  regarding the correlation of diabetic peripheral neuropathy and vitamin D deficiency. In this case-control study on 25 patients with diabetic peripheral neuropathy and 25 healthy controls, the authors performed a clinical assessment aimed at evaluating the degree of diabetic neuropathy through the Michigan Neuropathy Screening Instrument (MNSI), followed by a neurophysiological assessment in those with neuropathy. In addition, they measured the serum 25-OH vitamin D and defined the level of serum vitamin D as sufficient, insufficient, and deficient (more than 30 ng/mL, between 20 and 30 ng/mL, and below 20 ng/mL, respectively). Interestingly, they observed a significantly lower vitamin D plasma level in patients with diabetic neuropathy than in healthy controls (p = 0.008). Subsequently, the authors performed a subgroup analysis observing a lower value of serum vitamin D in female patients and in patients with a MNSI score above 4 (p = 0.03 and p = 0.006, respectively). However, the correlation analysis between vitamin D levels and the degree of peripheral neurologic impairment showed no significant difference.
We believe that this study allows a few interesting considerations. The burden of diabetes all over the world is widely recognized, as it is estimated that its prevalence is around 400 million people and figures predict a constant increase in its incidence . Due to the complexity of its pathophysiology, its impact on neurological impairment ranges from acute conditions as coma  or electrolytic disturbances  to a chronic peripheral neuropathy  which, although not immediately life-threatening, leads to a consistent drop in the patient’s quality of life. In this context, a growing evidence is suggesting an important role of vitamin D deficiency. In this particular regard, the findings of Oraby and colleagues are coherent with those of Abdelsadek and colleagues  which on a cohort of 80 patients enlightened the role of vitamin D deficiency in the development of diabetic neuropathy. They elegantly demonstrated not only that patients with neuropathy had lower levels of Vitamin D, but also that low vitamin D levels are an independent risk factor for the development of diabetes-related peripheral damages (OR 0.941 [0.856–0.976]; p = 0.007) . In this context, the immunoregulatory and anti-inflammatory activity of vitamin D might play a role, as well as in other inflammatory disorders such as rheumatoid arthritis [7, 8].
Despite these interesting results [1, 6], the road to reach a full comprehension of the pathophysiological role of vitamin D in diabetic neuropathy development is still long. In the presence of many confounders, the single weight of vitamin D deficiency on the development of such complication still needs to be clarified. Moreover, since the different strategies of antidiabetic therapy might significantly affect vitamin D values , the role of a therapeutic vitamin D regimen either as a prevention or as a treatment should be specifically investigated.
In conclusion, these two studies add important pieces to the diabetes-related neuropathy issue. As the line is drawn, a multicenter randomized controlled trial might help to complete the puzzle.
Oraby MI, Srie MA, Abdelshafy S, Elfar E. Diabetic peripheral neuropathy: the potential role of vitamin D deficiency. Egypt J Neurol Psychiatry Neurosurg. 2019;55:10.
Roglic G, World Health Organization, editors. Global report on diabetes. Geneva: World Health Organization; 2016.
Bartoli E, Sainaghi PP, Bergamasco L, Castello L. Hyperosmolar coma due to exclusive glucose accumulation: recognition and computations. Nephrol Carlton Vic. 2009;14:338–44.
Bartoli E, Sainaghi PP, Bergamasco L, Castello L. Computation of the excess glucose and Na deficit of hypo-osmolar hyponatremic hyperglycaemia. Acta Diabetol. 2010;47:147–54.
Tesfaye S, Boulton AJM, Dyck PJ, Freeman R, Horowitz M, Kempler P, et al. Diabetic neuropathies: update on definitions, diagnostic criteria, estimation of severity, and treatments. Diabetes Care. 2010;33:2285–93.
Abdelsadek SE, El Saghier EO, Abdel Raheem SI. Serum 25(OH) vitamin D level and its relation to diabetic peripheral neuropathy in Egyptian patients with type 2 diabetes mellitus. Egypt J Neurol Psychiatry Neurosurg. 2018;54:36.
Bellan M, Sainaghi PP, Pirisi M. Role of vitamin D in rheumatoid arthritis. Adv Exp Med Biol. 2017;996:155–68.
Bellan M, Pirisi M, Sainaghi PP. Osteoporosis in rheumatoid arthritis: role of the vitamin D/parathyroid hormone system. Rev Bras Reumatol. 2015;55:256–63.
Availability of data and materials
Ethics approval and consent to participate
Consent for publication
The authors declare that they have no competing interests.
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
About this article
Cite this article
Baldrighi, M., Avanzi, G.C. Comment to “Diabetic peripheral neuropathy: the potential role of vitamin D deficiency” by Oraby et al.. Egypt J Neurol Psychiatry Neurosurg 55, 27 (2019). https://doi.org/10.1186/s41983-019-0082-y
- Vitamin D
- Diabetic neuropathy