Relationships between Musculoskeletal Disorders, Sleep Impairment, and Cardiorespiratory Fitness among Adolescents Aged 15-19 Years in Douala, Cameroon: A Cross-sectional Study

Background: Musculoskeletal disorders (MSDs) are a leading cause of disability worldwide. While poor sleep quality (PSQ) is considered an important risk factor for pain, high cardiorespiratory fitness (CRF) is a somewhat controversial protective factor. The present study investigated the association between MSDs, PSQ, and CRF in adolescents.Methods: A cross-sectional, prospective study was conducted from November 2023 to March 2024 in Douala, Cameroon, among 15-to 19-year-old adolescents from public and private secondary schools. MSDs over the past three months (MSDs-3m) and the past week (MSDs-7d), as well as PSQ, were assessed using the Nordic and Pittsburgh sleep quality questionnaires, respectively. Then, CRF was estimated using the 20-meter shuttle run test. Quantitative analyses were performed using a t-test and qualitative by the chi-square test, respectively. Also, logistic regression was used to identify associations between MSDs, PSQ, and CRF, with statistical significance set at P<0.05.Results: A total of 549 adolescents were included with a female predominance (64.5%). The respective prevalence rates for PSQ, MSDs-3m and MSDs-7d were 64.1%, 60.3% and 44.3%. MSDs were predominantly found in adolescents with PSQ (MSDs- 3m: 52.8%, P=0.007; MSDs-7d: 64.5%, P<0.001). The neck (MSDs-3m=40.3%) and lower back (MSDs-7d=23.3%) were the body parts most affected in adolescents with PSQ. Neck pain was associated with MSDs (P<0.01) and an increase in all PSQ components, with sleep disturbances being mostly associated with MSDs in body regions (P<0.01). No association (P>0.05) was noticed between CRF and MSDs.Conclusion: PSQ was a significant risk factor for MSDs in adolescents, whilst CRF did not protect against MSDs.