Low back pain disparities in Portugal: a population-based study analysing the role of social determinants of health

Introduction: Despite growing research, the relationship between social determinants of health (SDoH) and low back pain (LBP) remains inconsistent. This study aimed to investigate the associations between SDoH and self-reported LBP in the Portuguese population in 2019 and explore potential differences between rural and urban areas. Methods: This is a cross-sectional study that includes 13,230 participants from the 2019 Portuguese National Health Interview Survey. Multivariable logistic regression models were used to assess the associations between SDoH and LBP. Interaction effects were examined to determine whether these relationships are modified by the degree of urbanisation/rurality. Results: The regression model for demographic and economic determinants showed associations between LBP and sex, age, marital status, education and financial capacity, with older rural residents having a higher likelihood of reporting LBP. The psychosocial model revealed that poor health status, sleep disturbances, fatigue, and dissatisfaction with life course were positively associated with LBP. In the behavioural model, obesity and history of smoking increased the probability of reporting LBP, whereas exercise behaviours reduced it and significantly varied across urban and rural regions. Health-system factors, including hospital visits, medication use, consultations with rehabilitation professionals, delayed healthcare access, and unmet health needs due to financial constraints, were associated with LBP. Rural residents were more likely to seek outpatient care at hospitals. Discussion: These findings emphasise the importance of integrating the evaluation of SDoH into healthcare settings to develop tailored interventions for LBP management. Conclusion: LBP was influenced by several SDoH, but differences between rural and urban areas were limited.