Association between low back pain and psychological stress response in a Japanese population-based study

Background: Psychological stress response refers to the negative emotional states generated when an individual perceives that they do not have the resources to cope with or respond to a threat. Low back pain (LBP) is a complex condition with multiple contributors, including psychological factors. However, whether LBP is a stressor that causes a psychological stress response remains unknown. This study aimed to investigate the association between LBP and psychological stress response in a Japanese populationbased cohort. Methods: Participants aged >50 years were recruited from inhabitants of a mountain village in Japan. The participants completed the following patient-reported outcome measures. The extent of the psychological stress response was measured using the Stress response scale (SRS)-18, which includes the subscales "Depression/Anxiety", "Irritability/Anger", and "Helplessness". LBP intensity in several situations/positions was measured using a numerical rating scale (NRS). Quality of life (QOL) was measured using the Oswestry Disability Index, EuroQol 5-dimension, and EuroQol visual analog scales. The association between SRS-18 and each parameter was statistically evaluated. Results: A total of 282 participants (72.1 years old) were analyzed in this study, and 29.1% had chronic LBP. The SRS-18 total score of all participants ranged from 0 to 43, and the average SRS-18 total score was 7.7 +/- 8.8 (depression/anxiety: 2.3 +/- 3.2, irritability/anger: 2.4 +/- 3.3, helplessness: 2.9 +/- 3.2). SRS-18 scores of participants with LBP were significantly higher than those of participants without LBP. SRS18 scores were significantly correlated with QOL scores (P < 0.01, correlation coefficient 1/4 0.22-0.46). Multiple regression analysis showed that the NRS score of LBP during morning awakening was significantly associated with the SRS-18 total, depression/anxiety, and helplessness scores. Conclusions: Psychological stress responses were associated with LBP and LBP-related QOL among residents of a Japanese mountain village.