Association between smoking and central sensitization pain: a web-based cross-sectional study.

PURPOSE: This study aimed to investigate whether smoking is an independent risk factor for central sensitization syndrome (CSS) in individuals with pain as measured by the Central Sensitization Inventory (CSI). METHODS: In 2020, we conducted an Internet survey targeting 2000 ordinary residents of Japan (aged 20-69 years) who had pain symptoms from October to November 2020. A multiple regression analysis was performed on the association between smoking status (nonsmokers and current smokers; Brinkman index) and CSI values. Moreover, compared to nonsmokers, the relative risk (RR) of the CSI cut-off score of 40 points or higher among current smokers was calculated using a modified Poisson regression model. Covariates included age, sex, body mass index, marital status, equivalized income, exercise habits, history of hypertension, history of hyperlipidemia, history of diabetes, pain chronicity, and Pain Catastrophizing Scale score. RESULTS: This study analyzed 1,822 individuals (1,041 men and 781 women). Among those experiencing pain, current smoking was associated with the increase in CSI values (ß = 0.07). The Brinkman index was also significantly associated with the increase in CSI values (ß = 0.06). Current smoking also increased the risk of being over the CSI cut-off score, with a relative risk (RR) of 1.29 (95% confidence intervals, 1.04-1.60). Younger age, being women, experiencing chronic pain, and higher pain catastrophizing thinking were also significantly associated with increased CSS severity, independent of smoking status. CONCLUSION: Smoking is an independent risk factor for CSS. This indicates that smoking may be an important factor in the management of central pain disorders.

Sex-Specific Impact of Pain Severity, Insomnia, and Psychosocial Factors on Disability due to Spinal Degenerative Disease.

Purpose: Pain experience due to spinal degenerative disease decreases activity of daily living and quality of life. The present cross-sectional study was aimed at examining the sex-specific impact of pain severity, psychosocial factors, and insomnia on the disability due to chronic pain arising from spinal degenerative disease. Methods: In total, 111 outpatients with chronic spinal degenerative on initial diagnosis were analyzed. The definition of chronic spinal degenerative disease was (1) pain duration ≥3 months, (2) findings of nerve root compression on neurological examination and imaging, and (3) localized neck or lower back pain (not widespread, upper or lower limb pain). We used Numerical Rating Scale (NRS), Pain Disability Assessment Scale (PDAS), Hospital Anxiety and Depression Scale (HADS), Pain Catastrophizing Scale (PCS), and Athens Insomnia Scale (AIS) to assess patients. Univariate regression analysis was performed to investigate whether sex influences the PDAS score, and sex-stratified multivariate regression analysis was conducted to identify the variables associated with the PDAS score. Results: Sex was identified as a predictor of the PDAS score (standardized coefficient (ß) = 0.28; 95% confidence interval (CI), 0.10-0.46; p=0.003). In men, the AIS score was associated with PDAS (ß = 0.36, 95% CI 0.09-0.63). Age (ß = 0.31, 95% CI 0.06-0.55) and NRS (ß = 0.40, 95% CI 0.14-0.67) were associated with PDAS in women. HADS-A, HADS-D, and PCS were not associated with PDAS in both sexes. Conclusion: Insomnia was associated with disability in men, whereas aging and pain severity were associated with disability in women. Catastrophic thinking was not associated with disability in both sexes.

Association between change in self-efficacy and reduction in disability among patients with chronic pain.

PURPOSE: This study aimed to investigate whether changes in psychosocial factors and pain severity were associated with reduction in disability due to pain among patients with chronic pain. We hypothesized that increased self-efficacy would reduce disability. PATIENTS AND METHODS: This longitudinal observational study included 72 patients. Patients' psychological and physical variables were assessed before and after 3 months of treatment. Demographic and clinical information were collected, including the Pain Disability Assessment Scale (PDAS), the Pain Self-Efficacy Questionnaire (PSEQ), the Hospital Depression and Anxiety Scale, and the Numeric Rating Scale (NRS) to assess pain intensity. First, univariate regression analyses were conducted to clarify associations between change in PDAS and sex, age, pain duration, changes in psychosocial factors (self-efficacy, anxiety, and depression) and change in pain intensity. Second, multivariate regression was conducted using the variables identified in the univariate analyses (PSEQ and NRS) to detect the most relevant factor for reducing disability. RESULTS: Univariate regression analyses clarified that changes in PSEQ (ß = -0.31; 95% CI: -0.54--0.08, p = 0.008) and NRS (ß = 0.24; 95% confidence interval [CI]: 0.01-0.47, p = 0.04) were associated with reduction in PDAS. Multivariate regression analysis demonstrated that change in PSEQ (ß = 0.26; 95% CI: -0.50--0.02; p = 0.01) was associated with a reduction in disability, independent of change in NRS. CONCLUSION: These findings suggest improved self-efficacy is associated with reduced disability in patients with chronic pain, independent of reduction in pain intensity. Focusing on improvement in self-efficacy may be an effective strategy in chronic pain treatment in addition to pain relief.