Vitamin D deficiency is associated with painful diabetic neuropathy

Abstract

BackgroundThe aetiology of painful diabetic neuropathy is unclear. We have evaluated vitamin D levels in diabetic patients with and without painful neuropathy.MethodsForty‐three patients with type 1 diabetes and painless (DPN) (n = 20) or painful (PDN) (n = 23) neuropathy and 14 non‐diabetic healthy control subjects (C) underwent assessment of neurologic deficits, quantitative sensory testing (QST), electrophysiology, skin biopsy, corneal confocal microscopy (CCM) and measurement of serum 25(OH)D.ResultsThere were no significant differences for age, BMI, HbA1c, lipids, neurological deficits, QST, electrophysiology, intra‐epidermal nerve fibre density (IENFD) and corneal nerve morphology between patients with DPN and PDN. Both positive (hyperalgesia and allodynia) and negative symptoms (paraesthesia and numbness) of diabetic neuropathy were greater in PDN compared with DPN (P = .009 and P = .02, respectively). Serum 25(OH)D levels were significantly lower in PDN (24.0 ± 14.1 ng/mL) compared with DPN (34.6 ± 15.0 ng/mL, P = .01) and controls (34.1 ± 8.6 ng/mL, P = .03). The odds ratio in favour of painful diabetic neuropathy was 9.8 [P = .003 (95% CI, 2.2–76.4)] for vitamin D deficiency (<20 ng/mL) and 4.4 [P = .03 (95% CI, 1.1‐19.8)] for vitamin D insufficiency (<30 ng/mL).ConclusionsThis study suggests that vitamin D deficiency and insufficiency are associated with painful diabetic neuropathy.

Better Islet Function and Cardiovascular Autonomic Function in Chinese Type 2 Diabetic Patients with Pure Small Fiber Neuropathy than with Mixed Neuropathy

“…We noted that the level of vitamin D was lower in the mixed DPN group than in the non-DPN group, which is in line with results from several previous studies [ 15 – 17 ]. Possible mechanisms include a role of vitamin D in protecting Schwann cells against advanced glycation end product (AGE)-induced apoptosis [ 18 ] and the promotion of proangiogenic molecules [ 19 ].…”

Better Islet Function and Cardiovascular Autonomic Function in Type 2 Diabetic Patients With Pure Small Fibre Neuropathy Than With Mixed Neuropathy

“…We noticed that the level of vitamin D was lower in the mixed DPN group than in the non-DPN group, which was in line with several previous studies [14][15][16]. Possible mechanisms include vitamin D protecting Schwann cells against advanced glycation end product (AGE)-induced apoptosis [17] and promoting proangiogenic molecules [18].…”

Assessment of Serum Vitamin D Levels in the serum of Patients with Postherpetic neuralgia and its correlation to pain severity: A cross‐sectional comparative study

“…Patients with lower back pain had their pain severity negatively correlated with their vitamin D levels 40 . Vitamin D deficiency is associated with painful diabetic neuropathy in type 2 DM 41,42 . In patients with rheumatoid arthritis, the severity of neuropathic pain was negatively associated with vitamin D levels ( P = .001), and neuropathic pain was 5.8 times higher in patients with serum levels of vitamin D < 20 ng/ml than those above 30 ng/ml 43 …”