Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 60 5 2022 06 08 283 292 Rawdha Tekaya Department of Rheumatology, Charles Nicolle Hospital, Tunis, Tunisia . AND Faculty of Medicine of Tunis, University Tunis el Manar, Tunis, Tunisia. Ons Hamdi Department of Rheumatology, Charles Nicolle Hospital, Tunis, Tunisia. AND Faculty of Medicine of Tunis, University Tunis el Manar, Tunis, Tunisia Ines Jemmali Faculty of Medicine of Tunis, University Tunis el Manar, Tunis, Tunisia . AND Department of Biochemistry, Charles Nicolle Hospital, Tunis, Tunisia Aicha Ben Tekaya Department of Rheumatology, Charles Nicolle Hospital, Tunis, Tunisia 2 Faculty of Medicine of Tunis, University Tunis el Manar, Tunis, Tunisia Leila Rouached Department of Rheumatology, Charles Nicolle Hospital, Tunis, Tunisia . AND Faculty of Medicine of Tunis, University Tunis el Manar, Tunis, Tunisia. Olfa Saidane Department of Rheumatology, Charles Nicolle Hospital, Tunis, Tunisia, AND Faculty of Medicine of Tunis, University Tunis el Manar, Tunis, Tunisia Selma Bouden Department of Rheumatology, Charles Nicolle Hospital, Tunis, Tunisia. AND Faculty of Medicine of Tunis, University Tunis el Manar, Tunis, Tunisia Kahena Bouzid Faculty of Medicine of Tunis, University Tunis el Manar, Tunis, Tunisia . AND Department of Biochemistry, Charles Nicolle Hospital, Tunis, Tunisia Ines Mahmoud Department of Rheumatology, Charles Nicolle Hospital, Tunis, Tunisia. AND Faculty of Medicine of Tunis, University Tunis el Manar, Tunis, Tunisia Leila Abdelmoula Department of Rheumatology, Charles Nicolle Hospital, Tunis, Tunisia . AND Faculty of Medicine of Tunis, University Tunis el Manar, Tunis, Tunisia 2020 10 07 2021 12 09 Fatigue is a common symptom in ankylosing spondylitis. Hypovitaminosis D is one of the factors influencing fatigue during inflammatory rheumatisms. This study aimed to determine the influence of vitamin D deficiency on fatigue in ankylosing spondylitis. In this cross-sectional study, 40 patients with ankylosing spondylitis and 40 patients suffering from low back pain were recruited. Clinical and laboratory data, including vitamin D dosage, disease activity, functional impairment, and quality of life, were evaluated using specific and validated scores. Fatigue was assessed by the FACIT-F score. Both groups of patients were compound of 27 men and 13 women with a mean of 43.55±12.26 years in the study group and 47.77±13.63 years in the case group, respectively. Ankylosing spondylitis was active according to the ASDASCRP score in 67.5% of cases. All patients were suffering from fatigue with a mean FACIT-F score of 21.13. Severe levels of fatigue were noted in 50% of cases. 92.5% of patients were vitamin D deficient with a mean vitamin D of 16.57±7.15 ng/mL. Factors associated with fatigue were: female gender (P=0.05), spinal pain (P<0.001), enthesitis (P<0.001), disease activity (P<0.001), functional impairment (P<0.001), and quality of life (P<0.001). However, smoking was the only factor related to vitamin D deficiency (P=0.05). Vitamin D level was not correlated with fatigue (r= -0.02, P=0.91). In our study, vitamin D status did not seem to have an impact on fatigue in patients with ankylosing spondylitis. https://acta.tums.ac.ir/index.php/acta/article/view/8854