Serum vitamin D levels in patients with Bell's palsy: a systematic review and meta-analysis. - Foroughi, Elaheh; Mozafar, Mehrdad; Haghighi, Shayesteh; Baerz, Maryam Moghbel; Torabi, Kosar Salehi; Bafti, Aref Hafezi; Asadi, Fatemeh; Askari, Mani Khorsand; Shahabinejad, Erfan (BMC Neurology, 2025)