Yukiko Shiro

Background/Objectives: The prevalence of pain increases with age, particularly in middle-aged women, when sex hormone levels fluctuate drastically. While climacteric symptoms and their relationship with pain have been extensively studied in women, it remains unclear whether these symptoms and their association with pain are limited to women. This study aimed to investigate the association between climacteric symptoms and pain in both women and men. Methods: A cross-sectional online survey using a non-probability quota panel conducted in March 2024 assessed the presence, location, and intensity of pain during the past 28 days (numerical rating scale ≥ 1, irrespective of pain duration) among 6000 Japanese adults aged 30–59 years (3000 women, 3000 men). Climacteric symptoms were assessed using the Simplified Menopausal Index for women and the Aging Males’ Symptoms scale for men. Quality of life was assessed using the EQ-5D-5L. Pain intensity was analyzed only in participants with pain (433 women, 488 men). Results: As symptom scores increased, both men and women showed higher pain prevalence and intensity and lower quality of life. Symptom scores were positively correlated with pain intensity in both sexes (Spearman’s ρ = 0.35 in women, 0.39 in men), with no evidence of a sex difference (interaction p = 0.991). Somatic scores showed the strongest associations (standardized β = 0.21 in women, 0.22 in men), followed by vasomotor symptoms in women (β = 0.16) and psychological symptoms in men (β = 0.20). The associations remained after excluding pain-related items. Conclusions: Climacteric symptoms were associated with pain intensity in both men and women, without clear evidence of a sex difference. Causality cannot be inferred from this cross-sectional design; prospective studies are needed.

Background: Chronic low back pain (CLBP) is associated with impaired muscle performance, including reduced trunk strength, as well as disturbances in body perception. Virtual reality (VR) enables modulation of body representation, and the Proteus effect suggests that embodying a stronger avatar may influence perceived bodily capability and behavior. Although preliminary CLBP studies have reported short-term improvements in pain and beliefs, it remains unclear whether avatar-based embodiment can acutely modify muscle strength or relate to subjective embodiment. Objective: This study aimed to examine immediate changes in muscle strength and pain after a VR-based squat task with a progressively muscular avatar in individuals with CLBP and explore associations between strength changes and subjective embodiment. Methods: In this exploratory pre-post proof-of-concept study, 16 individuals with CLBP and 16 age- and sex-matched healthy controls performed a VR-based squat task with a progressively muscular avatar. Muscle strength (handgrip, trunk extension, and knee extension) was assessed before and after VR. Pain and fear were assessed in CLBP only. Subjective embodiment was assessed using the Virtual Embodiment Questionnaire (VEQ). Group × time effects were analyzed using repeated-measures ANOVA, and associations were analyzed using Spearman correlations with false discovery rate correction. All participants completed the VR-based task and assessments, and no missing data were observed in variables included in the analyses. Results: Significant time effects were observed for handgrip strength ( P =.04), trunk extension strength ( P <.001), and knee extension strength ( P <.001), whereas no significant group × time interactions were observed for handgrip, trunk extension, or knee extension strength ( P =.75, P =.19, and P =.28, respectively). Trunk extension strength significantly increased in healthy controls (mean difference 0.04 kgf/kg, 95% CI 0.03 to 0.05; Bonferroni-adjusted P <.001) but not in individuals with CLBP (mean difference 0.02 kgf/kg, 95% CI 0.001-0.05; Bonferroni-adjusted P =.08). Knee extension strength increased in both the CLBP group (mean difference 0.06 kgf/kg, 95% CI 0.02-0.11; Bonferroni-adjusted P =.02) and healthy controls (mean difference 0.09 kgf/kg, 95% CI 0.06-0.12; Bonferroni-adjusted P <.001). In the CLBP group, pain intensity decreased during VR compared with pre-VR levels ( P =.02), whereas post-VR pain did not differ from pre-VR levels. Changes in trunk extension strength were positively correlated with VEQ change in the CLBP group (ρ=0.76, 95% CI 0.41-0.94; false discovery rate–adjusted P =.006). Conclusions: Trunk and knee extension strength showed time-related increases without significant group × time interactions, and trunk extension strength change was associated with VEQ change in the CLBP group. These findings suggest that avatar-based modulation of body perception may relate to individual variability in motor output. However, without a neutral-avatar control condition, the observed changes cannot be attributed specifically to the progressive muscular transformation of the avatar. Further research is needed to clarify the role of avatar-based embodiment in exercise-based rehabilitation.

This study aimed to investigate the relationship between women’s health issues (WHI) and pain symptoms among Japanese female workers, influencing health–related quality of life (HRQOL) and work productivity. A population–based cross–sectional online survey targeting Japanese female workers aged 20–69 years was conducted in July 2023. A total of 3,564 participants with 2,999 valid responses were recorded. The prevalence of pain was 49.8%, with comorbidity rate of 29.9% for pain and WHI. The key risk factors included menstrual–related symptoms, menopausal symptoms, and pelvic floor disorders. The number of pain sites was greater in women experiencing both pain and WHI than in those experiencing pain alone. Women with menstrual, menopausal, and pelvic floor disorders reported more severe pain in multiple areas of the body, along with elevated levels of occupational stress, reduced HRQOL, increased psychological distress, and markedly higher levels of presenteeism than those with pain alone. Overall, this study highlights the coexistence of WHI, such as menstrual, menopausal, and pelvic floor disorders, with pain in female workers, which potentially exacerbates pain severity, lowers HRQOL, and negatively impacts work productivity. Therefore, addressing the WHI in female workers experiencing pain is crucial for alleviating the symptoms, enhancing HRQOL, and improving workplace productivity.

Background: There are many factors associated with chronic pain, including changes in the nervous and musculoskeletal systems and so on. Recently, it has become clear that the gut microbiota (GM) influences these factors, and there are many reports of GM dysbiosis in patients with chronic pain. However, the relationship between pain and GM remains unclear. Our previous study reported that defecation status, which reflects GM composition, was associated with pain intensity and that this relationship was different for each pain site. Our study investigated the association between pain site and the GM composition of feces in chronic pain patients. Methods: The subjects were 136 patients with chronic pain and 125 healthy controls. Patients were classified into four groups, whole body (WB) pain, lower back and lower extremity (LL) pain, headache, and upper back and upper extremity pain, based on the site of pain, and we investigated differences in GM taxonomy groups compared with healthy subject. Results: Chronic pain patients had a lower alpha diversity (effect size=0.16, p=0.02). But each pain site group did not differ in alpha diversity. WB pain patients showed higher Eggerthellaceae (LDA=3.09, p< 0.01) and lower Halomonas (LDA =− 2.72, p< 0.01). LL pain patients had increased Fusobacterium and Sellimonas (LDA=4.09,3.03 p< 0.01, 0.01) but reduced Halomonas (LDA=− 2.59, p< 0.01), and other key taxa. Conclusion: WB and LL patients may have GM compositions different from healthy controls, but larger studies are needed to confirm this.

The proportion of neck injuries due to traffic accidents is increasing. Little is known about high-cost patients with acute whiplash-associated disorder (WAD). The present study aimed to investigate whether time to first visit for conventional medicine, multiple doctor visits, or alternative medicine could predict high-cost patients with acute WAD in Japan. Data from a compulsory, no-fault, government automobile liability insurance agency in Japan between 2014 and 2019 were used. The primary economic outcome was the total cost of healthcare per person. Treatment-related variables were assessed based on the time to first visit for conventional and alternative medicine, multiple doctor visits, and visits for alternative medicine. Patients were categorized according to total healthcare cost (low, medium, and high cost). The variables were subjected to univariate and multivariate analysis to compare high-cost and low-cost patients. A total of 104,911 participants with a median age of 42 years were analyzed. The median total healthcare cost per person was 67,366 yen. The cost for consecutive medicine, for consecutive and alternative medicine, and total healthcare costs were significantly associated with all clinical outcomes. Female sex, being a homemaker, a history of WAD claim, residential area, patient responsibility in a traffic accident, multiple doctor visits, and visits for alternative medicine were identified as independent predictive factors for a high cost in multivariate analysis. Multiple doctor visits and visits for alternative medicine showed large differences between groups (odds ratios 2673 and 694, respectively). Patients with multiple doctor visits and visits for alternative medicine showed a significantly high total healthcare cost per person (292,346 yen) compared to those without (53,587 yen). A high total healthcare cost is strongly associated with multiple doctor visits and visits for alternative medicine in patients with acute WAD in Japan.

: The gut microbiota (GM) plays an important role in gut-brain communication, and the ‘gut-brain axis’ has attracted much attention as a factor influencing human host health. We previously reported that pain perception may be associated with GM composition in males. The aim of this study was to investigate the relationship between GM composition and pain perception among 42 healthy female university students in Japan. Pain perception was evaluated by pressure pain threshold (PPT), current perception threshold (CPT), temporal summation of pain (TSP), conditioned pain modulation (CPM), and a questionnaire on psychological state. CPT was stimulated at 5, 250, and 2,000 Hz, which reflected the thresholds of the C, Aδ, and Aβ fibers, respectively. Also, GM composition was estimated using 16S rRNA analysis. The lower alpha diversity was associated with, the lower PPT (rs = 0.330, P < 0.05) and CPT of 2000 Hz (re = 0.339, P < 0.05). Furthermore, alpha diversity was identified as an explanatory variable for PPT (β = 0.424, P < 0.01) and TSP (β = -0.317, P < 0.05), alpha diversity and state anxiety for CPT of 2000 Hz (β = 0.321, P < 0.05), and state anxiety for CPT of 250 Hz (β = 0.320, P < 0.05). However, there was no relationship between the rate of major phylum and pain perception.

Purpose: The purpose of the present study was to investigate the visual attentional behavior towards a pain-affected area and face/body images using eye tracking in complex regional pain syndrome (CRPS) patients. Moreover, we investigated the relationship between visual attentional behavior and clinical symptoms. Patients and methods: Eight female patients with CRPS type 1 in their upper limbs and 8 healthy adult women participated in this study. First, the participants were asked to watch videoclips in a relaxed manner (Videoclip 1 featured young adults who introduced themselves; Videoclip 2 featured young adults touching the hand of the other person sitting across from them with their hand.) Eye movement data were tracked with eye-tracking glasses. Results: In video clip 1, the fixation duration (FD) and fixation count (FC) on faces tended to be lower in CRPS patients than in healthy controls. This tendency was found in patients with low body cognitive distortions. In video clip 2, CRPS patients displayed significantly lower FD and FC on the unaffected hand while watching a video of the unaffected hand being touched compared with healthy controls. Moreover, patients with low body cognitive distortion displayed significantly longer FD on the affected hand. Conclusion: Some CRPS patients differed in visual attentional behavior toward the face and body compared with healthy controls. In addition, our findings suggest that patients with lower body cognitive distortion may have a high visual attention for the affected hand, while patients with higher distortion may be neglecting the affected hand.

Introduction Multidisciplinary pain management programs incorporating a cognitive-behavioral therapy (CBT) approach have been reported to be helpful for elderly people with chronic pain. However, it is unclear whether the same program for elderly people with chronic pain would translate to different cultures. This study investigated whether a multidisciplinary program based on that of Nicholas et al. (Pain 154(6):824–835, 2013) in Australia would be effective for elderly people with chronic pain in Japan. Methods Twenty-seven community-dwelling elderly people with chronic pain were enrolled to confirm changes (effect size d = 0.5) in pain disability, which were previously reported by Nicholas et al. The multidisciplinary program consisted of eight sessions (2 sessions a week for 4 weeks). Pain disability was assessed using the Pain Disability Assessment Scale (PDAS) as the primary outcome at the baseline, the beginning and the end of the program, and the 1- and 3-month (final) follow-up. We also assessed the pain severity, catastrophizing, pain self-efficacy, and physical function with the Timed Up and Go test (TUG) and the two-step test as secondary outcomes. Results PDAS, pain catastrophizing, and pain self-efficacy were significantly improved immediately after the program compared with baseline, and these effects were maintained at 3-month follow-up. The effect size (d) for the PDAS score was a medium size (0.54) from baseline to 3-month follow-up. Those who showed improvements in TUG immediately after the program tended to report improved psychometric measures at 3-month follow-up. Conclusion These results suggest that the Japanese multidisciplinary program has a similar effect on pain disability as that reported by Nicholas et al. This finding has important implications for the development of pain services in community-dwelling elderly Japanese.

Objective. Virtual reality (VR) is an advanced technology that can be used to attenuate pain. The present study aimed to investigate which method was more effective for pain management: VR combined with exercise imagery or VR distraction. Methods. Fifty-two healthy students participated in this randomized cross-over controlled trial. One VR-based task aimed to passively use the imagery of driving a car as a distraction intervention (the driving group), whereas the other VR-based task aimed to use exercise imagery (running) to actively engage the participants in movement (the running group). The mechanical pressure pain thresholds of the quadriceps and forearm and the heat pain threshold of the hand of each subject were measured before, during, and after each VR task. The differences between the values at each time point and the differences between the groups were analyzed. Results. The pressure and heat pain thresholds were significantly greater during VR task than those before VR task in both driving and running groups. The changes in the pressure pain thresholds that occurred during VR task were significantly higher in the running group than in the driving group. The difference between groups gradually declined after VR task. Conversely, there was no significant difference in the changes in the heat pain thresholds between the groups both during VR task and after VR task. Conclusions. VR combined with exercise imagery has a greater effect on pressure pain thresholds, but not heat pain thresholds, than VR distraction.

Anesthesiology and Pain Medicine