The Relationship of Serum Vitamin B12 and Ferritin Levels with Disease Severity and Neuropathic Pain in Fibromyalgia Syndrome.

Objective: To investigate the relationship of serum vitamin B12 (vB12) and ferritin levels with disease severity and neuropathic pain in fibromyalgia syndrome (FMS).

Study design: Observational study. Place and Duration of the Study: Department of Physical Medicine and Rehabilitation, Faculty of Medicine, Inonu University, Malatya, Turkiye, from October to December 2023.

Methodology: A total of 110 patients, aged between 18 and 65 years, diagnosed with FMS according to the 2016 ACR diagnostic criteria, were included in this study. The participants were evaluated using the Fibromyalgia Impact Questionnaire (FIQ) to measure symptoms impacting daily activities such as pain, sleep disturbances, and fatigue. The Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) is a clinical scale used to investigate the neuropathic component of pain. The serum levels of vB12 and ferritin were compared between the patients with and without neuropathic pain symptoms and the impact of these parameters on disease severity and activities of daily life was analysed.

Results: Among the participants, 105 were females and 5 were males. Sixty-nine patients reported neuropathic pain, while 41 did not. Patients with neuropathic pain had significantly higher VAS and FIQ scores and significantly lower vB12 and ferritin levels (p <0.05). A significant inverse relationship was found between FIQ scores and both vB12 levels (p = 0.047, r = -0.190) and ferritin levels (p = 0.007, r = -0.256).

Conclusion: In this study, fibromyalgia patients with neuropathic pain had higher pain and disease activity scores, and low serum vB12 and ferritin levels were found to be associated with disease severity and neuropathic pain.

Key words: Fibromyalgia syndrome, Neuropathic pain, Vitamin B12, Ferritin, Pain.