The impact of schoolbag weight and carrying style on musculoskeletal pain: A 5-year prospective cohort study among schoolchildren in Misrata, Libya

Background Musculoskeletal pain is a growing public health concern among school-aged children, with significant physical and psychosocial implications. Schoolbag weight and carrying style have been identified as critical ergonomic risk factors. However, evidence from developing countries, including Libya, remains limited, particularly regarding longitudinal impacts. Objective This study aimed to evaluate the association between schoolbag weight, carrying style, and musculoskeletal pain over a five-year period among elementary schoolchildren in Misrata, Libya. Methods A cohort of 443 elementary schoolchildren (grades 1–4) was followed for five years, with 421 completing all assessments. Data were collected on schoolbag weight, carrying style, walking duration, and pain characteristics. Descriptive statistics, Chi-square tests, and logistic regression were applied to explore the prevalence and predictors of pain. Repeated Measures ANOVA and Friedman tests were used to assess changes in continuous and categorical outcomes across time points. Results Musculoskeletal pain prevalence increased from 0.0% at baseline to 10.1% at the first follow-up before declining to 5.6% and 6.2% in subsequent follow-ups. Carrying style emerged as the most significant predictor of pain, with the mid-back (T12) style reducing the risk of pain by up to 98.8% compared to the low-back (L3) style. Schoolbag weight, while exceeding recommended thresholds, was not a significant predictor of pain. Gender differences were noted, with girls at higher risk during early follow-ups. Walking duration played a marginal role, influencing pain risk only in the first follow-up. Conclusion This study highlights the critical role of ergonomic carrying styles, particularly the mid-back (T12) position, in reducing musculoskeletal pain among schoolchildren. Findings challenge the conventional emphasis on bag weight alone and highlight the need for multifaceted interventions, including ergonomic education and policy changes, to promote musculoskeletal health.