Abstract
BACKGROUND: Back pain is influenced by biological, psychological, and social factors, yet is often investigated separately. METHODS: Cross-sectional analysis of the UK Biobank comparing well-being (Patient Health Questionnaire-4; 4-16 points; higher scores indicate greater levels of depressive and anxiety symptoms), number of stressful life events, C-reactive protein (CRP), and physical activity (International Physical Activity Questionnaire) among pain-free, acute, and chronic back pain individuals. The sample included 22,864 individuals: 5716 with acute back pain, 5716 with chronic back pain, and 11,432 pain-free controls. Group comparisons were performed using network analysis and analysis of covariance, adjusted for socioeconomic deprivation, body mass index, smoking, and alcohol consumption. RESULTS: Well-being was poorer in acute (mean difference [95% CI]: 0.20 [0.14, 0.25] points; p < 0.001) and chronic back pain (0.39 [0.34, 0.45] points; p < 0.001) compared to controls. More stressful life events were measured in acute (0.03 [0.01, 0.05] points; p = 0.041) and chronic back pain (0.03 [0.01, 0.05] points; p = 0.028) compared to controls. However, this finding was not robust to sensitivity analyses. Elevated CRP was found in acute (2.28 [0.57, 3.99]%; p = 0.024; ES = very small), but not in chronic back pain, compared to controls. No significant group differences were observed for physical activity. Network structures did not differ between groups. CONCLUSIONS: Differences in well-being and CRP among pain-free, acute, and chronic back pain individuals were identified, suggesting that variables may be affected by back pain temporality. Further prospective research incorporating additional variables is needed to explore the drivers of back pain. SIGNIFICANCE STATEMENT: Individuals with acute back pain showed 2% higher CRP than controls, though values remained within the normal range (< 5 mg/L) across groups and below clinical relevance, suggesting limited utility of CRP in distinguishing acute from chronic back pain. Poorer well-being in both acute and chronic back pain underscores the need to explore underlying causal pathways. Moreover, similar network structures among groups indicate no neuroimmune involvement in back pain onset or chronification based on the variables examined.