Russian University of Medicine; Dolgorukovskaya ul., 4, Moscow, 127006, Russian Federation

Introduction. The high prevalence of obesity increases the importance of understanding the control of disease progression and associated metabolic abnormalities. Recent studies have revealed melatonin as a cause of degenerative joint diseases and a molecular link between sleep disorders and metabolic diseases, due to its powerful biological functions that have a specific effect on the metabolism of osteochondral tissue. Thus, melatonin plays an important role in the regulation of the sleep/wake cycle, adaptation to environmental changes and is considered a key mediator of pathologi-cal processes such as osteoarthritis. Aim – to assess the severity of somnological disorders and the level of nocturnal secretion of the pineal hormone melatonin in patients with the meta-bolic phenotype of osteoarthritis. Material and Methods. 80 patients has took part in the study. Participants were divided into 2 groups: group 1 – patients without joint pathology and normal body mass index; group 2 - patients with the metabolic phenotype of osteoarthritis. The subjects underwent a collection of complaints, anam-nesis, as well as a general clinical and orthopedic examination. Serum melatonin levels were determined. Results. Patients with the metabolic phenotype of osteoarthritis showed dysfunction in scores on the subcomponents of sleep quality and quantity. Patients demonstrated a tendency to daytime sleepiness, dissatisfaction with sleep duration, and frequent awakenings at night, which may be due to pain and symptoms of osteoarthritis. It was found that patients with the metabolic phenotype of osteoarthritis showed a decrease in nocturnal excre-tion of the pineal gland hormone melatonin in comparison with patients in group 1. Conclusions. The findings support the growing evidence of a significant interaction between melatonin secretion and metabolically associated diseas-es.