Vitamin D, Chronic Migraine, and Extracranial Pain: Is There a Link? Data From an Observational Study

Several studies focused on the role of vitamin D (vitD) in pain chronification. This study focused on vitD level and pain chronification and extension in headache disorders. Eighty patients with primary headache underwent neurological examination, laboratory exams, including serum calcifediol 25(OH)D, and headache features assessment along with three questionnaires investigating depression, anxiety and allodynia. The 82.6% of the population had migraine (48% episodic and 52% chronic). The 45% of patients had extracranial pain and 47% suffered from allodynia. A VitD deficit, namely a serum 25(OH)D level less than of 20 ng/ml, was detectable in 45.8% of the patients, and it occurred more frequently (p=0.009) in patients suffering from chronic migraine (CM)- medication overuse migraine (MOH) (64.7%) than in episodic migraine (EM) or tension type headache (TTH). The occurrence of extracranial pain and allodynia was higher in the CM-MOH than in the EM and in the TTH groups, but was not related to the co-occurrence of vit-D deficiency (Fischer’s exact test p=0.11 and p=0.32 respectively). Our findings show that 25(OH)D deficit is related to chronic in headache also, probably because of vitD anti-inflammatory and tolerogenic properties, reinforcing the idea of a neuroinflammatory mechanism underpinning migraine chronification.