Does Vitamin D deficiency play a role in peripheral neuropathy in Type 2 diabetes?

Diabet. Med. 29, 43–49 (2012)

Abstract

Aim  Despite recent reports linking vitamin D deficiency with increased risk of diabetes mellitus and complications, there is limited data on patients with diabetic peripheral neuropathy. We aimed to evaluate the incidence and associations of vitamin D deficiency in 210 patients with Type 2 diabetes with and without diabetic peripheral neuropathy.

Methods  Renal, liver, lipid profile and HbA_1c were measured. Vitamin D status was determined by measuring 25-dihydroxyvitamin D. Presence or absence of coronary heart disease was determined and early-morning urine microalbumin:creatinine ratio was measured. All patients were assessed clinically using neuropathy symptom score, neuropathy disability score and nerve conduction study.

Results  Eighty-seven patients had diabetic peripheral neuropathy and these patients had significantly longer duration of diabetes and higher HbA_1c. Age, gender, incidence of retinopathy and coronary heart disease were not significantly different from those without neuropathy. Mean (SD) vitamin D was significantly lower in those with neuropathy [36.9 (39.9) nmol/l] compared with those without [58.32 (58.9) nmol/l] and 81.5% of patients with neuropathy had vitamin D deficiency compared with 60.4% of those without. Vitamin D showed significant (P < 0.05) correlations with total cholesterol, LDL-cholesterol and urine microalbumin:creatinine ratio. Binary logistic regression analysis showed that diabetic peripheral neuropathy was significantly associated with vitamin D deficiency (odds ratio = 3.47; 95% CI = 1.04–11.56, P = 0.043) after inclusion of potential confounders such as duration of diabetes, HbA_1c and LDL-cholesterol.

Conclusion  Vitamin D deficiency is an independent risk factor for diabetic peripheral neuropathy, and further studies are required to confirm if Vitamin D supplementation could prevent or delay the onset.