Serum magnesium levels and their association with sleep quality and disease severity in fibromyalgia syndrome: An observational cross-sectional study.

Fibromyalgia syndrome (FMS) is a multifactorial condition characterized by chronic widespread pain, fatigue, and sleep disturbances, often accompanied by biochemical and psychosocial alterations. Sleep quality plays a critical role in disease severity and patient functionality. Recent evidence suggests that magnesium may influence both pain and sleep regulation. This observational cross-sectional study aimed to investigate the relationship between sleep quality and serum magnesium levels in patients with FMS and to explore their associations with clinical characteristics such as pain severity and functional status. Eighty-two patients diagnosed with FMS were grouped based on their Pittsburgh Sleep Quality Index (PSQI) scores: PSQI ≤ 5 (n = 27) and PSQI > 5 (n = 55). Demographic and clinical parameters, including age, body mass index, tender points, Fibromyalgia Impact Questionnaire (FIQ), and serum magnesium levels, were compared between the groups. Correlation analyses were performed to assess associations between magnesium levels and clinical variables. No significant differences were found between the groups in terms of age and body mass index (P > .05 for all). The PSQI > 5 group demonstrated significantly higher tender points (P = .035), visual analog scale scores (P = .002), FIQ scores (P < .001), and lower serum magnesium levels (P = .038) compared to the PSQI ≤ 5 group. Significant negative correlations were observed between magnesium levels and tender points (ρ = -0.293, P = .008), visual analog scale score (ρ = -0.252, P = .023), FIQ scores (ρ = -0.242, P = .028), PSQI scores (ρ = -0.324, P = .003). The findings indicate that lower serum magnesium levels are associated with poorer sleep quality, higher pain severity, and greater functional impairment in patients with FMS. These findings suggest a potential link between magnesium levels and the pathophysiology of sleep disturbances in FMS. However, due to the cross-sectional nature of the study and possible confounding influences, further longitudinal and interventional research is required to determine whether magnesium supplementation could offer clinical benefits in this population.