Responding holistically: Does total U.S. state safety net support generosity prevent child maltreatment?

Spinal pain is a highly prevalent musculoskeletal disorder worldwide, imposing a substantial burden on patients’ quality of life, functional status, and socioeconomic well-being. According to data from the Global Burden of Disease Study, more than 628 million people globally were affected by low back pain in 2021, with Chinese patients accounting for as high as 16%. Low back pain has become the leading cause of disability worldwide, particularly prevalent among middle-aged and elderly populations. Despite a decline in age-standardized prevalence, the absolute number of cases and disability-adjusted life years (DALYs) continue to rise, indicating that the disease burden of spinal pain is still increasing. Epidemiological studies further reveal significant gender and age differences in the distribution of spinal pain: females not only have higher prevalence and incidence rates than males but also bear a heavier disease burden. Notably, the clinical course of spinal pain is highly heterogeneous – some patients achieve rapid recovery, while others may experience persistent or fluctuating functional impairment. This variability is closely associated with multiple biopsychosocial factors. The comorbidity of spinal pain and depressive disorders has attracted increasing attention in clinical practice, with its underlying mechanisms involving complex physiological and psychological pathways. Chronic pain can induce dysfunctions of the neuroendocrine and immune systems by activating the hypothalamic-pituitary-adrenal (HPA) axis and proinflammatory cytokine networks, thereby contributing to the development of depressive symptoms. On the other hand, depressive states may exacerbate pain experiences by lowering pain thresholds, intensifying central sensitization of pain perception, and prompting patients to adopt negative coping strategies. This bidirectional mechanism is particularly prominent in the elderly population. Studies have shown that back pain can predict the occurrence of sleep problems within the subsequent 6 years, while sleep disorders fail to predict the onset of back pain, indicating the temporal impact of pain on psychological status. In addition, psychological factors such as pain catastrophizing and fear-avoidance beliefs have been identified as important predictors of pain-related functional impairment, with their influence even exceeding that of pain intensity itself. In terms of clinical prognosis, spinal surgery patients with comorbid depressive symptoms exhibit a higher risk of residual pain, highlighting the key role of psychological factors in the chronicization of pain. Previous studies have explored the association between spinal pain and depressive symptoms scores from multiple aspects, but several limitations remain. Cross-sectional studies are difficult to establish the direction of causality, while most longitudinal studies have failed to fully control for potential confounding variables. Although some studies have indicated that biopsychosocial characteristics affect disability trajectories in a cumulative and dose-dependent manner, individual outcomes cannot be fully predicted based on baseline characteristics alone. In recent years, large-scale population studies have provided new perspectives for understanding this association. Research has found that there is a significant interaction between activities of daily living (ADLs) and sleep duration on low back pain – especially among adults aged 60 years and above, short sleep combined with limitations in basic activities of daily living (BADLs) exhibits an additive interaction. In addition, the regulatory role of dyslipidemia in the association between depressive symptoms and spinal pain has received increasing attention. Interaction analysis shows it is statistically significant, although the low mediation proportion suggests that its pathway may be dominated by effect modification rather than a mediating mechanism. These findings emphasize the importance of considering the complex interactions of multiple physiological and metabolic factors when investigating the relationship between depressive symptoms and pain.