AUTHOR=Xiaohua Gong , Dongdong Luo , Xiaoting Niu , Shuoping Chen , Feixia Shen , Huajun Yang , Qi Zhou , Zimiao Chen 

TITLE=Severe Vitamin D Deficiency Is Associated With Increased Expression of Inflammatory Cytokines in Painful Diabetic Peripheral Neuropathy

JOURNAL=Frontiers in Nutrition

VOLUME=8

YEAR=2021

URL=https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2021.612068

DOI=10.3389/fnut.2021.612068

ISSN=2296-861X

ABSTRACT=<p><bold>Background:</bold> The exact pathogenic mechanism of the painful diabetic peripheral neuropathy (DPN) is poorly understood. Our study aimed to evaluate the association amongst vitamin D status, inflammatory cytokines, and painful DPN.</p><p><bold>Methods:</bold> A total of 483 patients were divided into three groups, i.e., diabetes without DPN (no-DPN, <italic>n</italic> = 86), diabetes with painless DPN (painless DPN, <italic>n</italic> = 176) and diabetes with painful DPN (painful DPN, <italic>n</italic> = 221) groups. Basic information and laboratory results were collected. The concentrations of vitamin D (25-hydroxyvitamin D), high-sensitivity C-reactive protein, interleukin (IL)-2, IL-4, IL-6, IL-10, tumor necrosis factor-α (TNF-α), and interferon-γ (IFN-γ) were also measured.</p><p><bold>Results:</bold> The prevalence of severe vitamin D deficiency (&lt;10 ng/mL) was more common in the painful DPN group than in the painless DPN and no-DPN groups (25.8,12.5, and 8.1%, respectively, <italic>P</italic> &lt; 0.01). Cases in the painful DPN group had significantly higher concentrations of IL-6 (<italic>P</italic> &lt; 0.01) and TNF-α (<italic>P</italic> &lt; 0.01) than those in the two other groups. The multivariate logistic analysis showed that severe vitamin D deficiency, IL-6, and TNF-α were independent risks for painful DPN after adjusting for confounding factors. Furthermore, the vitamin D status had significantly negative correlations with IL-6 (<italic>r</italic> = −0.56, <italic>P</italic> &lt; 0.01) and TNF-α (<italic>r</italic> = −0.47, <italic>P</italic> &lt; 0.01) levels.</p><p><bold>Conclusion:</bold> Severe vitamin D deficiency was an independent risk factor for the painful DPN. Severe vitamin D deficiency status may play a role in the painful DPN pathogenesis through elevated IL-6 and TNF-α levels.</p>