Sex, gender, and pain: a review of recent clinical and experimental findings

Sex, gender, and pain: Evidence and knowledge gaps

Sex and gender contribute to the variation in pain experience. A range of biological, psychological, and social factors are relevant, which point to potential pain mechanisms and the reasons for this sex/gender-based variation. This review provides a brief critical overview of the evidence for these patterns. It draws on both experimental and clinical studies and identifies some of the biological and psychosocial factors that are thought to impact on men and women's pain. There are limitations and gaps in understanding, and numerous challenges exist, ranging from difficulties with concepts through to methodology. There is a focus on gender as a dimensional set of psychosocial constructs, as this offers one approach to help enhance our understanding of men and women's pain.

Alcohol and cannabis use for pain management: Translational findings of relative risks, benefits, and interactions

Chronic pain affects over 20% of the global population and contributes to the vast burden of psychiatric illness. While effective treatments for chronic pain remain limited, both alcohol and cannabis have been used for centuries to manage pain and closely associated negative affective symptoms. However, persistent misuse of alcohol and/or cannabis in such a negative reinforcement fashion is hypothesized to increase the risk of severity of substance use disorders (SUDs). The current review describes neurobiological evidence for the analgesic efficacy of alcohol and primary cannabis constituents and how use or co-use of these substances may influence SUD risk.

Differential effect of three types of exoskeletons and handling height on muscular activity, postural control and perceived effort during simulated bedside mobilization task

Home care workers are affected by musculoskeletal disorders caused by biomechanical factors. This study investigated the effect of three exoskeletons devices (HAPO, HAPO FRONT and Japet.W) during load mobilization tasks at three bed heights in order to reduce physical risk factor. Anterior deltoid and longissimus bilateral muscular activities were recorded by EMG, a force platform was used to record center of pressure (CoP) displacement, and perceived exertion parameters were assessed using the Borg scale while nineteen healthy subjects performed a load manipulation. The use of the HAPO FRONT decreased global muscular activity by 5,6% and deltoid activity by 10,7%, exoskeletons reduced perceived effort, from 42% to 25%. Bed height has an inverse effect on deltoid and longissimus activity. These findings show that exoskeletons can reduce perceived effort and for overall and deltoids muscular activity. Therefore, the combination of shoulder and low back assistance appears as an interesting line of thought.

Inclusive healthcare for people with intellectual disabilities: The impact of labelling and biomedical causal beliefs

BACKGROUND

People with intellectual disabilities often face inequalities in healthcare, including a lack of sensitivity on the part of healthcare professionals who are less able to identify and recognise these people's health needs despite the desire to make healthcare accessible.

AIMS

This study examined the links between variables related to intellectual disability literacy and variables related to stigma which may be related to healthcare professionals' sensitivity to the health needs of people with intellectual disabilities.

METHOD AND PROCEDURE

An online cross-sectional survey was conducted with 163 healthcare professionals. Participants were randomly assigned to one of the following vignettes, with two presentation conditions (labelled or unlabelled) and two gender conditions (male or female), and the participants were asked to complete an intellectual disability literacy scale (IDLS, Scior & Furnham, 2011).

RESULTS

Only 31 % of healthcare professionals in the unlabelled condition recognise a neurodevelopmental disorder. Furthermore, the label predicts an attribution of biomedical causal beliefs and fewer environmental causal beliefs than the unlabelled condition. Moreover, the belief in a biomedical cause predicts a reduction in social distance. Finally, gender and label seem to affect social distance.

CONCLUSIONS AND IMPLICATIONS

Healthcare professionals are not sufficiently aware of intellectual disability (i.e., recognition of symptoms, causes of the disorder). These findings seem all the more important given that our results indicate that attributing a biomedical cause to a person's situation helps reduce social distance, which is an essential element in caring for people. It therefore seems essential to promote practices aimed at improving access to inclusive healthcare.

Pain predicts past-month co-use of alcohol and cannabis among emerging adults: Results from the Population Assessment of Tobacco and Health (PATH) Study

Alcohol use, cannabis use, and pain are public health concerns among emerging adults (18-24 years old). Co-use of alcohol and cannabis is of particular concern since individuals who co-use alcohol and cannabis use more of each substance and experience greater substance-related harm. Pain and substance use frequently co-occur, and a growing body of literature indicates pain is unique risk factor for substance use. The goal of the current study was to examine moderate/severe pain (vs. no/low pain) as a prospective predictor of engaging in co-use of alcohol and cannabis among emerging adults, and to test sex as a moderator of this hypothesized relationship. Data were drawn from Waves 1-5 of the Population Assessment of Tobacco and Health Study (n = 3544). Unadjusted logistic regression revealed that those with moderate/severe pain at baseline were 1.4 times more likely to engage in past-month co-use of alcohol and cannabis over the next four years (p = .046). The effects of pain on co-use were no longer significant after inclusion of covariates and a pain∗sex interaction term, which was also nonsignificant (ps > .05). These findings provide initial support for pain as a risk factor for engaging in co-use of alcohol and cannabis during emerging adulthood. Future research should continue investigating how pain may motivate co-use of alcohol and cannabis, exploring how pain is associated with other measures of co-use, and determining how providers can incorporate pain-substance use psychoeducation for emerging adults in clinical settings.

The spectrum of anguish from osteoarthritis sparks physiological or psychological needs in the young-old and the old-old determined by gender

Knee osteoarthritis (KOA) inducing physiological pain and psychological health which is a public health issue in the older adults. However, research about the gender-specific effects on young-old and old-old is still scarce. The aim was to explore the vulnerability of physiology and psychology to KOA among the young-old and the old-old by gender. This case-control study recruited participants from health examinations at the Tri-Service General Hospital between March 2015 and October 2019. The Western Ontario and McMaster Universities Arthritis Index (WOMAC) and the 12-item short-form survey (SF-12) were used to evaluate the health status and quality of life (QoL) of subjects. Kellgren-Lawrence grading system (KL) was adopted to assess knee radiographs of subjects, KL grade ≥ 2 as KOA patients (KL grade ≥ 3 as severe KOA patients) and KL grade < 2 as controls. Student t-test and χ2 test were used to compare the distribution differences between KOA patients and controls, including demographic data, health statuses and QoL. The association of KOA and QoL was determined using multiple regression analysis. There were 772 subjects (young-old, n = 543; old-old, n = 229) in this study, 406 KOA patients (including 85 severe KOA patients) and 366 healthy individuals. In the young-old, KOA may play a least role in health status and QoL. However, in the old-old, males with severe KOA would cause a decrease in SF-12 mental component summary score (MCS) (β= -13.75, 95% CI: -23.90 to -3.61); however, females with severe KOA would cause a decrease in SF-12 physical functioning domain (β = -19.44; 95% CI: -35.32 to -3.56). The spectrum of anguish from KOA leads to differential reduction of QoL determined by age and gender. This study provides a glimpse on physiological and psychological need among the young-old and the old-old with KOA by gender.

Gender disparities in myotonic dystrophy 1

Myotonic Dystrophy Type 1 (DM1) is a complex, inherited disorder characterized by significant clinical heterogeneity, affecting multiple organ systems with varying severity and age of onset. It is a multisystemic disorder with a wide range of clinical presentations that lead to symptoms and complications associated with various body systems. Predicting the overall phenotype and prognosis is challenging due to the lack of a single determining factor, complicating medical management and clinical trials. While extensive research has explored the genetic and molecular mechanisms of DM1, the influence of gender on disease manifestations, progression, and outcomes remains elusive. Emerging evidence suggests that male patients often experience greater morbidity and mortality with severe muscular, cardiac, central nervous system, and respiratory impairments, while females are more prone to ophthalmological, gastrointestinal, and endocrine complications. Potential gender-based differences in inheritance patterns also require further investigation. Despite these disparities, gender-specific considerations are largely absent in clinical management and research, limiting the development of targeted therapeutic strategies. This review provides a comprehensive analysis of gender-related differences in DM1, emphasizing their implications for disease prognosis, diagnosis, and treatment. Recognizing gender as a crucial factor in DM1 research and clinical practice could improve patient outcomes and more personalized therapeutic approaches.

Multi-omics profiles of chronic low back pain and fibromyalgia-Study protocol

BACKGROUND

Chronic low back pain (CLBP) and fibromyalgia (FM) are leading causes of suffering, disability, and social costs. Current pharmacological treatments do not target molecular mechanisms driving CLBP and FM, and no validated biomarkers are available, hampering the development of effective therapeutics. Omics research has the potential to substantially advance our ability to develop mechanism-specific therapeutics by identifying pathways involved in the pathophysiology of CLBP and FM, and facilitate the development of diagnostic, predictive, and prognostic biomarkers. We will conduct a blood and urine multi-omics study in comprehensively phenotyped and clinically characterized patients with CLBP and FM. Our aims are to identify molecular pathways potentially involved in the pathophysiology of CLBP and FM that would shift the focus of research to the development of target-specific therapeutics, and identify candidate diagnostic, predictive, and prognostic biomarkers.

METHODS

We are conducting a prospective cohort study of adults ≥18 years of age with CLBP (n=100) and FM (n=100), and pain-free controls (n=200). Phenotyping measures include demographics, medication use, pain-related clinical characteristics, physical function, neuropathic components (quantitative sensory tests and DN4 questionnaire), pain facilitation (temporal summation), and psychosocial function as moderator. Blood and urine samples are collected to analyze metabolomics, lipidomics and proteomics. We will integrate the overall omics data to identify common mechanisms and pathways, and associate multi-omics profiles to pain-related clinical characteristics, physical function, indicators of neuropathic pain, and pain facilitation, with psychosocial variables as moderators.

DISCUSSION

Our study addresses the need for a better understanding of the molecular mechanisms underlying chronic low back pain and fibromyalgia. Using a multi-omics approach, we hope to identify converging evidence for potential targets of future therapeutic developments, as well as promising candidate biomarkers for further investigation by biomarker validation studies. We believe that accurate patient phenotyping will be essential for the discovery process, as both conditions are characterized by high heterogeneity and complexity, likely rendering molecular mechanisms phenotype specific.

Gender-Specific Differences in Sedation-Associated Outcomes During Complex Electrophysiological Procedures

Background: Interventional electrophysiology is a rapidly advancing field, with sedation essential for patient comfort and immobility during complex electrophysiological procedures (EPS). However, sedatives and analgesics can cause respiratory depression and hypotension. Gender-specific differences (GDs) are often overlooked in medical research, as protocols and dosages are typically based on male subjects, potentially compromising treatment safety and efficacy for women. This study examines GDs in CO2 levels, respiratory rate, arterial blood pressure (ABP), and anesthetic requirements during deep sedation for EPS. Methods: This prospective study at Ulm University Heart Center included 702 patients (405 men and 297 women) treated under deep sedation between August 2019 and October 2023. Standard monitoring included an electrocardiogram (ECG) with heart rate, non-invasive ABP, oxygen saturation (SpO2), and a frequent venous blood gas analysis (vBGA). The primary composite endpoint was GDs in SpO2 dips below 90% and pathological vBGA changes. Results: The primary composite endpoint was reached by 177 women (59.6%) and 213 men (52.6%), showing no significant difference (p = 0.102). Women had a 1,6-fold higher risk of experiencing SpO2 dips below 90% (p = 0.001). Additionally, women had 1.7 times higher hypoxia rates (p < 0.001) and were 1.5 times more likely to have a mean ABP below 65 mmHg (p < 0.001). On average, they received 65.3 mg less total propofol than men (p = 0.005) and a higher midazolam dose per kilogram of body weight (p < 0.001). Conclusions: Although the primary composite endpoint showed no significant GDs, secondary outcomes highlight the need to consider gender-specific sedation adjustments, particularly for women. This study underscores the need for personalized sedation management and patient monitoring regarding GDs.

Investigating the Prevalence and Level of Pain Experienced by Australian Farmers

OBJECTIVES

This study evaluated the prevalence and level of pain in Australian farmers and how these compare to the general working population. We also explored factors related to the interference of pain on farmers' work.

DESIGN

Logistic regressions were used to examine the prevalence of chronic pain and pain interference with normal work among farmers compared to the general working population, and also to examine the factors associated with pain interference in farmers. A multinomial logistic regression model was used to examine the level of bodily pain among farmers compared to the general working population.

SETTING

The nationally representative HILDA (Household, Income, and Labour Dynamics Australia) survey data (wave 21) was used.

PARTICIPANTS

The final sample included 168 (1.6%) farmers and 10 318 (98.4%) people in the general working population.

RESULTS

There was a higher prevalence of chronic pain (p < 0.001), higher levels of bodily pain (p < 0.001), and pain interference with normal work (p < 0.001) in farmers than in the general working population. Age, gender, Body Mass Index (BMI), education level, remoteness, and personal social cohesion were not associated with pain interference with normal work in farmers.

CONCLUSION

The prevalence of chronic pain, level of bodily pain, and pain interference with normal work in Australian farmers is higher than the general working population. However, information is lacking on the factors that influence pain for this unique group. Further exploration is needed into why factors that are commonly associated with pain are not associated with pain in the farming population.

Sex, Neural Networks, and Behavioral Symptoms Among Adolescents With Multisite Pain

Importance

Multisite pain disproportionately affects females starting in adolescence and is associated with central nervous system dysregulation. Understanding the heterogeneity of underlying neural networks and behavioral symptoms is essential.

Objective

To characterize sex-related resting-state neural networks and co-occurring symptoms, including sleep and behavioral problems, in youth with multisite pain.

Design, Setting, and Participants

This cross-sectional analysis leverages the 2-year follow-up data from the Adolescent Brain and Cognitive Development Study. A total of 684 youth aged 11 to 12 years with multisite pain were compared with 1368 youth with no pain or with regional pain, matched by pubertal status, handedness, and race and ethnicity. Data were collected from July 2018 to February 2021 and released October 2021. Data were analyzed from June 2023 to July 2024.

Exposure

Youth-reported number of painful regions during the last month classified into multisite (≥3), regional (1-2), and no pain groups.

Main Outcomes and Measures

Sex-stratified group iterative multiple model estimation was used for sparse network estimation of regions from the salience network (SLN), sensorimotor network (SMN), and default mode network (DMN). Individual within-network and between-network densities were calculated. Symptoms were behavioral problems and sleep disturbances. Sex-stratified differences in network densities and symptoms were examined between groups. Associations between brain networks and co-occurring symptoms were explored.

Results

Of 2052 participants (1044 [50.88%] female), mean (SD) pubertal status was 2.23 (0.65) and mean (SD) age was 12.02 (0.66) years; 25 (1.22%) were Asian, 149 (7.26%) were Black, 361 (17.59%) were Hispanic, 1307 (63.69%) were White, and 210 (10.23%) were other race or ethnicity. A total of 1646 participants (80.21%) were right-handed, 100 (4.87%) were left-handed, and 306 (14.91%) were ambidextrous. Multisite pain was associated with lower within-SMN connectivity in male (F2,1005 = 61.40; η2 = 0.11; false discovery rate [FDR] P < .001) and female (F2,1041 = 13.38; η2 = 0.03; FDR P < .001) participants and was associated with greater behavioral problems in male (F2,918 = 28.12; η2 = 0.04; FDR P < .001) and female (F2,945 = 9.12; η2 = 0.02; FDR P < .001) participants compared with the subgroup with no pain. Male participants with multisite pain had heightened DMN-SMN connectivity (F2,1005 = 3.55; η2 = 0.007; FDR P = .04). Female participants with multisite pain had heightened sleep disturbances (F2,1039 = 10.64; η2 = 0.02; FDR P = .002), partially explained by reduced within-SMN connectivity (indirect effect estimate, 0.15; 95% CI, 0.03-0.34).

Conclusions and Relevance

In this cross-sectional study of 2052 adolescents, sex-related neurophysiological mechanisms were associated with multisite pain. Brain connectivity partially explained the sleep-pain association in female participants only. On replication and evidence of persistence, these findings suggest that female adolescents with pain may especially benefit from interventions targeting sleep disturbances.

Endogenous pain modulation is not different in basketball or volleyball athletes with patellar tendinopathy compared to asymptomatic athletic controls

BACKGROUND

Patellar tendinopathy is highly prevalent in basketball and volleyball athletes. Despite pain being the main symptom reported, underlying mechanisms are unclear.

OBJECTIVES

Our primary aim was to compare endogenous pain inhibition using a conditioned pain modulation protocol in basketball and volleyball athletes with patellar tendinopathy to asymptomatic athletic controls. Our secondary aim was to compare endogenous pain facilitation using a temporal summation protocol.

DESIGN

Cross-sectional case-control.

METHODS

Twenty-six athletes and 19 asymptomatic controls participated. We calculated the difference in PPT at the patellar tendon over the most painful site (pain site), the ipsilateral tibialis anterior (regional site), and the contralateral elbow lateral epicondyle (remote site), before and after immersion of the hand (ipsilateral to pain site) in painful cold-water. PPT change was used to quantify endogenous pain inhibition. Participants rated pain on a numerical rating scale (NRS; 0 = no pain to 10 = worst pain imaginable) at five, 20, 60 and 120 s during the cold-water immersion task. Change in NRS from five to 20 s quantified temporal summation.

RESULTS

Median symptom duration in our patellar tendinopathy group was 39 (IQR 22.5-55.5) months, and 85% experienced symptoms bilaterally. We did not observe alterations in endogenous pain inhibition at any site, or in temporal summation, in athletes with patellar tendinopathy compared to controls (p > 0.05).

CONCLUSION

Our findings indicate that altered central nervous system function is not a predominate feature contributing to pain in jumping athletes with patellar tendinopathy. Accordingly, clinicians should view pain as being of a local tissue source if targeting this symptom.

Subjective risk factors of severe pain at discharge from the emergency department

OBJECTIVE

To examine the risk factors for severe pain upon discharge from the emergency department, assuming appropriate pharmacological treatment of pain, in order to improve pain relief in emergency departments and reduce the risk of potential chronic pain.

METHODS

An analytic study was conducted utilizing data from a multicenter randomized controlled trial to evaluate patients' experiences upon admission and discharge from the emergency department (ED). Severe pain was defined by a score of six on a numerical rating scale of zero to ten. Stress and negative emotions (including anger, fear, sadness, and regret) were evaluated using numerical rating scales, respectively ranging from 0 to 10 and 1 to 5. The risk factors of severe pain at discharge (SPD) from ED were calculated using logistic regression considering patient characteristics evaluated at their admission to the ED.

RESULTS

From the 1240 patients analyzed, 22.2% had SPD from the ED. Each increase of one point in the intensity of acute pain and anger was significantly associated with a higher risk of SPD from ED. In addition, woman, negative self-perceived health, and age under 65 years, are other significant factors associated with SPD from the ED.

DISCUSSION

In addition to acute pain on admission, this study highlights new factors to consider when managing pain in emergency care, such as anger, and self-perceived health. Addressing these aspects can help reduce the likelihood of developing SPD from the ED, which in turn could potentially lead to the onset of chronic pain in future.

CLINICAL TRIAL REGISTRY

SOFTER IV Project clinical identification number: NCT04916678.

The role of androgens on experimental pain sensitivity: a systemic review and meta-analysis

Animal studies have shown androgens, especially testosterone, may have an analgesic effect on nociceptive behavior. However, it is unclear if this effect is present in humans. This review and meta-analysis aim to summarize and synthesize the role of androgens on experimental pain sensitivity in humans. Studies were included if they examined the (1) relationships between androgens and experimental pain sensitivity, (2) group differences in androgen or pain levels, and (3) the effect of androgen interventions on experimental pain sensitivity. After a comprehensive search, 31 papers were identified. When possible, meta-analyses were performed. Most studies examined the impact of testosterone on experimental pain, and only a few studies focused on other androgens, such as dehydroepiandrosterone and dehydroepiandrosterone sulfate. Overall, the current data do not support the effect of androgens on experimental pain sensitivity in adult men and women with or without chronic pain. In addition, meta-analyses of Pearson correlations did not find relationships between testosterone levels and pain ratings of heat stimulus (3 studies, n = 93, Z correlation coefficient = -0.43, confidence intervals [-1.50, 0.64]) or electrical pain thresholds (4 studies, n = 147, Z correlation coefficient = 0.24, confidence intervals [-0.10, 0.58]). Moreover, contradicting results were found in intervention studies that increased or decreased testosterone levels. Thus, it is suggested that the role of testosterone on experimental pain sensitivity may be minor, even though there is a wide heterogeneity between studies. Future studies should examine the impact of other androgens and the interaction between testosterone and other hormones on experimental pain sensitivity.

Evaluation of a Four Week Interdisciplinary Multimodal Pain Therapy on Chronic Pain Patients-A Comprehensive Approach

Chronic pain syndrome poses a significant challenge to healthcare systems worldwide, affecting millions of individuals and resulting in reduced quality of life and substantial socio-economic costs. This prospective, non-interventional, single-center study evaluated the effectiveness of a four-week interdisciplinary multimodal pain therapy (IMPT) program incorporating neuromuscular training with the HUBER® 360 evolution device. The study included 66 patients diagnosed with chronic pain disorder, divided into an intervention group (n = 49) that completed weekly supervised HUBER® 360 sessions and a control group (n = 17). Measurements were taken at four time points: day of admission (t1), during therapy (t2), at discharge (t3), and three months post-discharge (t4). The study assessed changes in psychological factors, pain intensity, postural control, and quality of life. The results show that this four-week therapy led to significant improvements in psychological factors such as depression, anxiety, and stress, and significantly reduced the subjects' pain. The intervention group showed more pronounced improvements compared to the control group. These findings highlight the potential benefits of IMPT in managing chronic pain and improving both physical and psychological health outcomes. This study contributes to the ongoing development of chronic pain management strategies, emphasizing the importance of a multidisciplinary, patient-centered approach. Future research should explore the scalability of IMPT, stratify results based on demographic factors, and evaluate the long-term efficacy of adjunctive tools like the HUBER® 360 device.

Electronic health record associations in patients self-reporting to be difficult to anesthetize

Background

Patients who report to be difficult to anesthetize for dental procedures are commonly encountered. Determining their frequency and shared characteristics could improve understanding of pain management failures.

Methods

Categorical and continuous variables of 24 demographic, medical history, and dental history variables were compared in a deidentified cross-sectional study using electronic health records (EHR) of patients at the University of Iowa College of Dentistry. Individuals who self-reported to be difficult to anesthetize in their dental health history form were compared to those who reported no complications with local anesthesia. Descriptive, univariate regression, and multivariable regression statistical analyses were completed on the demographic, medical history, and dental history EHR variables.

Results

A total of 12,400 deidentified patient records met the inclusion criteria with a 11.4% (n = 1,411) prevalence of difficult to anesthetize self-reports. Eight categorical variables were found to have statistically significant (95% confidence interval [CI]) adjusted odds ratios (AOR) in the multivariable regression of difficult to anesthetize reporting patients: female gender (AOR = 1.61, 95% CI: 1.32-1.96, P < 0.001), dental fear (AOR = 3.60, 95% CI: 3.01-4.31, P < 0.001), mental health disorders (AOR = 1.21, 95% CI: 1.00-1.46, P < 0.045), problems with general anesthesia (AOR = 1.46, 95% CI: 1.11-1.89, P = 0.005), neurological/nerve disorders (AOR = 1.30, 95% CI: 1.05-1.60, P = 0.015), temporomandibular joint clicking/popping (AOR = 1.31, 95% CI: 1.08-1.60, P = 0.006), needle anxiety (AOR = 29.03, 95% CI: 23.80-35.52, P < 0.001), and history of root canal treatment (AOR 0.82, 95% CI: 0.68-0.99, P = 0.035).

Conclusion

A clinically relevant percentage of patients self-reported being difficult to anesthetize for dental procedures. The relationship between local anesthesia inadequacies and variables such as female gender, dental fear, mental health, and neurological disorders requires further investigation. The use of evidence-based local anesthesia approaches and communication practices is suggested to minimize pain experienced and subsequent fear of dental care.

Global, Regional, and National Burden of Low Back Pain: Findings From the Global Burden of Disease Study 2021 and Projections to 2050

STUDY DESIGN

This was an observational study.

OBJECTIVE

Assessing the global burden of disease for low back pain (LBP) using the 2021 GBD (Global Burden of Disease) database.

SUMMARY OF BACKGROUND DATA

LBP is a leading cause of workforce loss and disability. With societal aging and changes in lifestyle and work habits, the incidence of LBP is expected to rise. This study comprehensively analyzes the epidemiological trends of global LBP from 1990 to 2021.

METHODS

Data publicly available from the 2021 GBD study were utilized, and a systematic analysis was conducted to assess the global burden and epidemiological trends of LBP.

RESULTS

From 1990 to 2021, the age-standardized prevalence, incidence, and Years Lived with Disability (YLD) rates of LBP have slightly declined globally. However, the number of affected individuals, new cases, and YLD numbers have significantly increased, making LBP a leading cause of YLD in 2021. The number of affected individuals increases with age, peaking in both men and women between the ages of 50 and 54. Worldwide, women have a higher prevalence of LBP than men, and this increases with age, with both sexes reaching peak prevalence between 80 and 84 years in 2021. Overall, over the past 3 decades, age-standardized YLD rates have shown a positive correlation with the Socio-demographic Index (SDI). In terms of region and nation, Tropical Latin America and Kingdom of Sweden have seen the greatest increase in age-standardized prevalence rates from 1990 to 2021.

CONCLUSION

Globally, LBP remains a notable public health concern, carrying a consistently high burden. To alleviate the future impact of this disease, it is imperative to increase public awareness regarding its risk factors and to implement preventive measures.

Sex and Strain Differences in Analgesic and Hyperlocomotor Effects of Morphine and μ-Opioid Receptor Expression in Mice

Sex and gender differences in the analgesic efficacy and side effects of opioids have been widely reported, but their underlying neurobiological mechanisms remain poorly understood. Preclinical animal models are essential tools for investigating these differences and providing insights into the neurobiology of opioid effects. Although studies in rats have revealed sex-specific effects of opioids, the sex-dependent behavioral profiles of opioids in mice, particularly across strains, remain largely unexplored. In this study, we characterized sex and strain differences in the antinociceptive and hyperlocomotor effects of morphine in the two most widely used mouse strains-CD1 and C57BL/6-and quantified regional expression of the μ-opioid receptor (MOR) in key brain and spinal cord regions. Both strains exhibited clear, dose-dependent antinociceptive and hyperlocomotor responses to morphine. While no significant sex or strain differences were observed in antinociceptive effects, C57BL/6 mice displayed significantly greater hyperlocomotor activity than CD1 mice. Western blot analyses revealed strain-specific MOR expression, with CD1 mice showing higher spinal cord and periaqueductal gray MOR levels, particularly in females, while C57BL/6 mice exhibited elevated MOR expression in the caudoputamen. Morphine treatment increased spinal MOR expression in CD1 mice but not C57BL/6, suggesting strain-dependent regulation of MOR. These findings highlight strain-specific behavioral and molecular responses to morphine, emphasizing the importance of strain and sex considerations in preclinical opioid research.

Genetic Variation and Sex-Based Differences: Current Considerations for Anesthetic Management

Biomedical sciences have made immense progress and numerous discoveries aimed at improving the quality of life and life expectancy in modern times. Anesthesiology is typically tailored to individual patients as its clinical effects depend on multiple factors, including a patient's physiological and pathological states, age, environmental exposures, and genetic variations. Sex differences are also paramount for a complete understanding of the effects of specific anesthetic medications on men and women. However, women-specific research and the inclusion of women in clinical trials, specifically during child-bearing years, remain disproportionately low compared to the general population at large. This review describes and summarizes genetic variations, including sex differences, that affect responses to common anesthetic medications such as volatile anesthetics, induction agents, neuromuscular blocking drugs, opioids, and local anesthetics. It also discusses the influence of genetic variations on anesthesia outcomes, such as postoperative nausea and vomiting, allergic reactions, pain, depth of anesthesia, awareness under anesthesia and recall, and postoperative delirium.

Patients' Experiences Participating Within an Interdisciplinary Primary Care Program for Low Back Pain

A common recommendation to improve the management of low back pain (LBP) is the use of interdisciplinary teams. However, many challenges remain in establishing interdisciplinary care, particularly in community-based primary care settings. This study explored patients' experiences with interdisciplinary care for LBP using an applied phenomenological research approach. Semistructured open-ended interviews were conducted with fifteen adults enrolled in a 6-month interdisciplinary LBP program within an integrated care network. The analysis included detailed descriptions of participants' experiences and interpretations by the researchers of the main themes: (i) challenging start-"It's intimidating," (ii) desire for flexibility-"I didn't need as much," (iii) better collaboration-"They are all together," (iv) grasping the pain issue-"They helped," (v) care was responsive to needs and experience-"Always centered on me, not general," (vi) meanings of recovery-"I'm able to function." Participants viewed the interdisciplinary LBP program as the culmination of a long journey toward recovery. The findings identified as important to patients contribute to our understanding of how to optimize patient-centered care for individuals living with chronic pain.

Sex-specific role of RNA-binding protein, pAUF1, on prolonged hypersensitivity after repetitive ischemia with reperfusion injury

ABSTRACT

Repetitive ischemia with reperfusion (I/R) injury is a common cause of myalgia. Ischemia with reperfusion injuries occur in many conditions that differentially affect males and females including complex regional pain syndrome and fibromyalgia. Our preclinical studies have indicated that primary afferent sensitization and behavioral hypersensitivity caused by I/R injury may be due to sex-specific gene expression in the dorsal root ganglia (DRG) and distinct upregulation of growth factors and cytokines in the affected muscles. To determine how these unique gene expression programs may be established in a sex-dependent manner in a model that more closely mimics clinical scenarios, we used a developed prolonged ischemic myalgia model in mice whereby animals experience repeated I/R injuries and compared behavioral results with unbiased and targeted screening strategies in male and female DRG. Several distinct proteins were found to be differentially expressed in male and female DRG, including phosphorylated AU-rich element RNA-binding protein (pAUF1), which is known to regulate gene expression. Nerve-specific siRNA-mediated knockdown of AUF1 inhibited prolonged hypersensitivity in females only, whereas overexpression of AUF1 in male DRG neurons increased pain-like responses. AUF1 knockdown was able to specifically inhibit repeated I/R-induced gene expression in females potentially downstream of prolactin receptor signaling. Data suggest RNA-binding proteins such as pAUF1 may underlie the sex-specific effects on DRG gene expression that modulates behavioral hypersensitivity after repeated I/R injury through prolactin signaling. This study may aid in finding distinct receptor differences related to the evolution of acute to chronic ischemic muscle pain development between sexes.

Epigenomic landscape of the human dorsal root ganglion: sex differences and transcriptional regulation of nociceptive genes

ABSTRACT

Cell states are influenced by the regulation of gene expression orchestrated by transcription factors capable of binding to accessible DNA regions. To uncover if sex differences exist in chromatin accessibility in the human dorsal root ganglion (hDRG), where nociceptive neurons innervating the body are found, we performed bulk and spatial assays for transposase-accessible chromatin technology followed by sequencing (ATAC-seq) from organ donors without a history of chronic pain. Using bulk ATAC-seq, we detected abundant sex differences in the hDRG. In women, differentially accessible regions (DARs) mapped mostly to the X chromosome, whereas in men, they mapped to autosomal genes. Hormone-responsive transcription factor binding motifs such as EGR1/3 were abundant within DARs in women, while JUN, FOS, and other activating protein 1 factor motifs were enriched in men, suggesting a higher activation state of cells compared with women. These observations were consistent with spatial ATAC-seq data. Furthermore, we validated that EGR1 expression is biased to female hDRG using RNAscope. In neurons, spatial ATAC-seq revealed higher chromatin accessibility in GABAergic, glutamatergic, and interferon-related genes in women and in Ca2+-signaling-related genes in men. Strikingly, XIST, responsible for inactivating 1 X chromosome by compacting it and maintaining at the periphery of the nucleus, was found to be highly dispersed in female neuronal nuclei. This is likely related to the higher chromatin accessibility in X in female hDRG neurons observed using both ATAC-seq approaches. We have documented baseline epigenomic sex differences in the hDRG which provide important descriptive information to test future hypotheses.

No gender difference in cardiac interoceptive accuracy: Potential psychophysiological contributors in heartbeat counting task

Gender differences in interoceptive awareness-awareness of internal bodily signals such as heartbeat perception-have been suggested, with some findings indicating behaviourally reduced but subjectively enhanced awareness in women, though these findings are still contentious. This study aimed to comprehensively examine gender differences in three aspects of interoceptive awareness: behavioural accuracy, subjective confidence, and relationship between them (i.e., metacognition). We used a modified heartbeat counting task that prohibited estimation strategies and increased the number of trials up to 20. Using data from 74 healthy young adults (39 women and 35 men), we evaluated gender differences and practice effects for each measure via Bayesian linear mixed models, controlling for individual heart rate and trial duration on a trial-by-trial basis. Contrary to previous research, the results revealed no reduced interoceptive accuracy in women; instead, higher interoceptive accuracy score was associated with shorter trial durations and lower heart rates regardless of gender. Moreover, women exhibited underconfidence about their performance, and therefore lower metacognition scores, compared to men. Trial repetitions moderated women's lowered metacognition but did not affect accuracy or confidence. These findings highlight potential physiological and psychological confounding factors in the heartbeat counting task, such as heart rate and reporting style, and emphasise several cautions for studying gender differences in interoceptive awareness.

Pain Predicts Cannabis Initiation Among Emerging Adults: Results from the Population Assessment of Tobacco and Health (PATH) Study

Pain is highly prevalent among emerging adults (18-25 years old), and rates of cannabis use are increasing among this population. Research indicates pain is a unique risk factor and motivator for substance use. However, evidence for pain-cannabis use relations among emerging adults is largely cross-sectional, and the only prospective evidence focuses on the frequency, quantity, and consequences of cannabis use, not initiation. Accordingly, this is the first study to examine pain as a prospective predictor of cannabis initiation among emerging adults. Data were drawn from five annual waves of the Population Assessment of Tobacco and Health Study. Emerging adults who denied cannabis use at baseline (n = 4,185) were included in the analysis. At baseline, a tenth of emerging adults reported moderate/severe pain (≥4/10). Adjusted Cox regression analysis revealed that emerging adults with moderate/severe baseline pain were more likely to initiate cannabis use, and did so earlier over the subsequent 4 years, than those with no/low baseline pain. These findings provide initial evidence for pain as a risk factor for cannabis initiation during emerging adulthood. Future research is needed to identify mechanisms by which pain motivates cannabis initiation and to examine the utility of pain-targeted content in cannabis use prevention and intervention efforts among emerging adults.

Pain Pressure Threshold as a Non-Linear Marker of Neural Adaptation in Amputees: Evidence from the DEFINE Cohort

BACKGROUND

Amputation poses significant physical, psychological, and emotional challenges, with chronic pain being one of the most debilitating outcomes. Pain Pressure Threshold (PPT), a measure of nociceptive sensitivity, is a valuable tool for assessing changes in pain perception. Understanding PPT modulation in amputees is crucial for uncovering the mechanisms underlying pain and developing targeted interventions for pain management.

OBJECTIVE

This study aimed to evaluate PPT in amputees and identify factors associated with PPT variation in this population.

METHODS

This cross-sectional study analyzed neurophysiological, clinical, and demographic data from 86 amputee patients. PPT was assessed as the primary outcome, and its associations with demographic and clinical predictors were examined using both linear and quadratic regression models.

RESULTS

Multivariate analysis identified a significant association between PPT and biological sex, with females exhibiting lower PPT values than males. Quadratic regression analyses revealed inverted U-shaped associations between PPT and age, BMI, and duration since amputation. PPT increased with age, peaking at 45.8 years, followed by a decline. Similar patterns were observed for BMI, peaking at 27.0 kg/m2, and for amputation duration, peaking at 26.6 months.

CONCLUSIONS

Our findings indicate that sex, age, BMI, and time since amputation are significant factors influencing PPT in amputees, with nonlinear relationships observed for age, BMI, and amputation duration. These results suggest that physiological and disease-related factors (such as age, BMI, and duration of injury) have specific peaks for optimal PPT, highlighting their role in the brain's compensatory system and potential implications for targeted pain management strategies.

Women are worse off in developing and recovering from temporomandibular disorder symptoms

Decision-making for temporomandibular disorders (TMDs) is reported being a clinical challenge, partly due to uncertainities in assessment of long-term prognosis. Therefore, our aim was to explore variations over time in TMD symptoms and possible sex or age differences. In this cohort study, data were prospectively collected 2010-2017 from the general population in Västerbotten, Northern Sweden. Adults were eligible if they had undergone at least two routine dental check-ups that included screening for TMDs (3Q/TMD) from which states were defined as absence or presence of TMD pain and/or jaw catching/locking. The rate of transitions was estimated between TMD states within a time span of one year. A total of 94,769 individuals were included (49.9% women) with 205,684 repeated visits and 9,006 state transitions recorded over the 8-year period. Compared to men, women had higher rates of transitions from no TMDs to any TMD symptoms. Furthermore, women had a lower rate of transition from TMD pain only to no TMDs. The finding of a poorer prognosis in women, as well as previously reported potential gender differences in pain perception and reporting, reinforces that gender differences should be accounted for in the treatment planning stage for patients with onset of TMDs.

The use of strong analgesics for prehospital pain management in children in the region of Southern Denmark: a register-based study

BACKGROUND

Acute pain in the prehospital setting is frequent and prehospital pain management presents multiple challenges, especially in children. There is a lack of high-level evidence regarding prehospital pain management in the paediatric population worldwide. In Denmark, this lack of evidence particularly concerns the frequency of the prehospital use of strong analgesics. Guidelines are sparse but there is evidence that prehospital fentanyl may be administered up to 5 µg/kg.

METHOD

This register-based study investigated the prehospital analgesic treatment in the population under 15 years from January 2017 to December 2022 in the Region of Southern Denmark. Data were extracted from electronic prehospital medical records. The analgesic treatment was characterised by the type of medication, dosage, administration method, and cause of ambulance dispatch. Lastly, response- and transport times were registered.

RESULTS

A total of 28,933 prehospital paediatric medical records were examined. In one in seventeen of all prehospital contacts with children, fentanyl, alfentanil, morphine and/or s-ketamine was administered. Three-quarters of the doses of strong analgesics were administered to patients older than 10 years. Fentanyl was the most frequently administered medication (96.4%). The median fentanyl-equipotent doses of opioids were 1.7 µg/kg adjusted according to standardised patient weight. In 63.4% of cases, the analgesic treatment was administered intravenously.

CONCLUSION

The doses of opioids as administered by the EMS personnel seem safe as 97% of the doses were within the recommended range and even at the lower end of the recommended range. Although apparently safe, the utilisation of strong analgesics points to a risk of under-treating pain in children.

Pain assessment and management of adult patients in the Swedish EMS: a nationwide registry study

BACKGROUND

Pain is a frequent reason for contacting the Emergency Medical Services (EMS), and effective pain management constitutes one of its cornerstones. The aims of this study have been: (a) to describe the prevalence of pain intensity ratings in EMS care of patients with pain-related conditions; (b) to describe pain treatment in the EMS setting in terms of drugs administered and the proportion of patients receiving analgesics and (c) to investigate the relationship between patients' self-reported pain intensity and vital signs.

METHODS

This is a retrospective observational cohort study using data from 394,700 EMS missions conducted 2021 and 2022, as recorded in the Swedish Ambulance Registry. The study focused on patients who contacted the EMS due to pain, trauma, or injury. Pain intensity was recorded using the Numeric Rating Scale (NRS). NRS scores of 5-10 were considered as high-level pain and NRS ≤ 4 as low-level. Descriptive statistics were used to present categorical and continuous variables. Chi-square tests were applied for dichotomous variables, while Kruskal-Wallis tests were used for ordinal data. Logistic regression analysis was carried out to identify factors associated with pain intensity and analgesic treatment. p value < 0.001 was considered statistically significant.

RESULTS

Pain intensity was recorded in 23.6% of cases. Most patients rated their pain as high-level (NRS 5-10, 57.4% of those assessed). Analgesics were administered in 27.5% of cases, with higher administration rates observed when pain intensity was documented. Female sex, higher breathing rates, and higher systolic blood pressure were associated with higher pain intensity, while increasing age was associated with lower odds of reporting high-level pain intensity. No significant association was found between heart rate and pain intensity.

CONCLUSION

This 2-year cohort study highlights significant deficiencies in recorded pain assessment and management in the Swedish EMS. Only 22.5% of the patients had their pain assessed with a validated scale, while 27.5% received analgesics, although pain-related conditions were a common reason for contacting the EMS. The findings indicate a lack of systematic pain assessment which puts many patients at risk of insufficient pain relief.

The Potential of a Robot Presence in Close Relationship to Influence Human Responses to Experimental Pain

Pain management is a critical challenge in healthcare, often exacerbated by loneliness and emotional distress. This study investigated the potential of a communication robot, Moffuly, to reduce pain perception and influence hormonal responses in a controlled experimental setting. Nineteen healthy participants underwent heat pain stimulation under two conditions: with and without robotic interaction. Pain levels were assessed using the Short-form McGill Pain Questionnaire and the Visual Analogue Scale, while mood and mental states were evaluated through established questionnaires including the Profile of Mood States, Hospital Anxiety and Depression Scale, and Self-Rating Depression Scale. Hormonal changes, including cortisol, growth hormone, oxytocin, estradiol, and dehydroepiandrosterone-sulfate, were measured from blood samples collected at key time points. The results demonstrated significant reductions in subjective pain and improvements in mood following robotic interaction. These effects were accompanied by favorable hormonal changes, including increased oxytocin and decreased cortisol and growth hormone levels. The findings suggest that robotic interaction may serve as an innovative approach to pain management by addressing both physiological and psychological factors. This study highlights the potential of robotics to complement traditional therapies in alleviating pain and enhancing emotional well-being. By mitigating emotional distress and loneliness, robotic interventions may enhance existing pain therapies and offer innovative solutions for resource-limited healthcare systems.

Personality and Its Influence on Pain Sensitivity Based on Different Hormonal Responses to Individual vs. Group Exercise Styles

Individual differences in pain sensitivity are thought to relate to personality traits, but the underlying mechanisms remain unclear. Exercise influences hormonal secretion via the hypothalamic-pituitary system, which may link personality, hormonal responses, and pain perception. This study investigated these relationships in 14 healthy participants (3 females, 11 males, aged 20-50 years, mean 28 ± 9.25 years). Participants rated thermal pain stimuli and completed the NEO Personality Inventory-Revised (NEO-PI-R) to identify their personality. Each participant engaged in personal and group training sessions, with blood samples collected to measure cortisol, growth hormone, and other indicators. Participants were clustered into cortisol hypersecretors and hyposecretors based on their hormonal response. Hypersecretors exhibited significantly lower neuroticism scores and pain ratings than hyposecretors. These findings suggest a potential association between cortisol responsiveness during exercise, neuroticism, and pain sensitivity. This study highlights potential links between personality traits and reactive hormonal patterns, offering insights into the psychophysiological mechanisms underlying pain expression.

Perceived Stress, Perceived Social Support, and Global Health in Adults with Chronic Pain

BACKGROUND

Chronic pain is a common problem in adults that can have a significant impact on individuals' quality of life and on society. The complex pain experience emerges from a dynamic combination of biological, psychological, and social factors. Previous research has shown that social support has positive effects on health-related outcomes through two mechanisms: direct-effects and stress-buffering effects. The aim of this study was to investigate the role that perceived stress, perceived social support, and their interaction play as predictors of global physical health and global mental health in adults with chronic pain.

METHOD

One hundred sixty-five adults with chronic pain completed measures of pain, perceived stress, perceived social support, global physical health, and global mental health.

RESULTS

Perceived stress but not perceived social support made a significant and independent contribution to the prediction of global physical health; both perceived stress and perceived social support made independent contributions to the prediction of global mental health. The perceived stress × perceived social support interaction did not make a significant contribution to the prediction of either criterion variable. The results suggested that perceived stress has an impact on both global physical and mental health, whereas perceived social support associated mostly with global mental health. In addition, perceived social support does not appear to moderate the impact of stress on global physical and mental health.

CONCLUSION

The findings are more consistent with a direct-effects model than a stress-buffering model of social support.

Experiences of Gender-Diverse Youth Living With Chronic Pain

BACKGROUND

Although sex differences in pain are well documented, little is known regarding the relationship between gender and pain. Gender-diverse youth experience unique pain risk factors, including minority stress exposure, but are underrepresented in research.

OBJECTIVE

Elicit experiences of gender-diverse youth who live with chronic pain.

METHODS

Semistructured interviews were conducted with youth virtually using Zoom. Youth were recruited from a Canadian tertiary care pediatric hospital, community-based clinics, and the general population. Interviews were recorded, transcribed, and analyzed with a patient partner using reflexive thematic analysis, integrating relevant existing theoretical and empirical models for understanding gender and pain, identity development, minority stress, and intersectionality.

RESULTS

The final sample included 19 youth who represented a variety of gender identities and pain conditions and reported accessing a range of types and levels of care. Three themes were identified through qualitative analysis: (1) the fight to legitimize both their pain and gender, (2) the tension between affirming gender and managing pain and the role of gender euphoria as a buffer against pain, and (3) the role of intersecting (eg, neurodiversity and race) identities in understanding gender-diverse youths' pain experiences.

CONCLUSIONS

In a diverse sample of gender-diverse youth who live with chronic pain, experiences of invalidation and difficulty managing pain were experienced in the context of unique stressors and sources of joy in living as a gender-diverse individual. These results point to the need for more intersectional and affirming pain research and integration of findings into clinical practice.

Histamine H3 receptor blockade alleviates neuropathic pain through the regulation of glial cells activation

Neuropathic pain is a disorder affecting the somatosensory nervous system. However, this condition is also characterized by significant neuroinflammation, primarily involving CNS-resident non-neuronal cells. A promising target for developing new analgesics is histamine H3 receptor (H3R); thus, we aimed to determine the influence of a novel H3R antagonist/inverse agonist, E-98 (1-(7-(4-chlorophenoxy)heptyl)-3-methylpiperidine), on pain symptoms and glia activation in model of neuropathic pain in male mice (chronic constriction injury to the sciatic nerve). We investigated the effects of single intraperitoneal (i.p.) (1, 5, 10, 20 mg/kg) and intrathecal (i.th.) (10, 30, 60 µg/5 µL) E-98-injections on mechanical (von Frey) and thermal (cold plate, tail flick) stimuli. The effect of chronic E-98 (10 mg/kg, i.p.) treatment and its influence on glia activation within the lumbar spinal cord was investigated. The anti-inflammatory properties of E-98 (10 µM) were screened in primary microglial and astroglial cell cultures. We assessed the presence of H3R within the spinal cord of control and neuropathic animals and in cell cultures. E-98 attenuated nociceptive responses in a dose- and time-dependent manner, and this effect is correlated with reduced microglia and increased astroglia activation. In vitro studies showed a decreased pro-inflammatory IL-6 level in both cell cultures. We observed co-localization of H3R with spinal neurons, microglia, and astrocytes and in primary glial cell cultures. We suggest that an analgesic effect of E-98 is partially due to the modulation of glial activation. We explore a new mechanism of H3R antagonists/inverse agonists analgesic action, bringing the potential benefits in pain management strategies.

Education, gender, and frequent pain among middle-aged and older adults in the United States, England, China, and India

ABSTRACT

Using cross-sectional data from the United States, England, China, and India, we examined the relationship between education and frequent pain, alongside the modification role of gender in this relationship. We further examined patterns of 3 pain dimensions among participants who reported frequent pain, including pain severity, interference with daily activities, and medication use (these pain dimension questions were not administered in all countries). Our analytical sample included 92,204 participants aged 50 years and above. We found a high prevalence of frequent pain across the 4 countries ranging from 28% to 41%. Probit models showed that higher education was associated with lower risk of pain (United States: -0.26, 95% CI: -0.33, -0.19; England: -0.32, 95% CI: -0.39, -0.25; China: -0.33, 95% CI -0.41, -0.26; India: -0.18, 95% CI -0.21, -0.15). Notably, in China and India, the negative association between higher education and frequent pain was less pronounced among women compared with men, which was not observed in the United States or England. Further analysis showed that individuals with higher education experiencing frequent pain reported less severity, fewer daily activity interferences, and less medication use compared with those with lower education. In the United States, these associations were stronger among women. Our findings highlight the prevalent pain among middle-aged and older adults in these 4 countries and emphasize the potentially protective role of higher education on frequent pain, with nuanced gender differences across different settings. This underscores the need for tailored strategies considering educational and gender differences to improve pain management and awareness.

Do female and male chests feel the same? A comprehensive quantitative sensory analysis

INTRODUCTION

There is growing interest in understanding chest sensory function due to the significant morbidity associated with impaired sensation following nerve injury. While the baseline quantitative sensory and pain thresholds in female and male patients have been studied in various other anatomic areas, there is little knowledge on quantitative sensation at the chest as well as the presence of possible gender differences. Therefore, this study aimed to conduct a comprehensive quantitative sensory analysis to determine if female and male chests feel the same.

METHODS

A total of 100 chests in 50 subjects (25 females and 25 males) were evaluated. Quantitative sensory testing (QST) was performed on the nipple areola complex (NAC) and surrounding chest skin and included mechanical detection using Semmes-Weinstein monofilaments, two-point discrimination, vibration detection, pin prick, cold detection, warm detection, heat pain and pressure pain thresholds.

RESULTS

Male chests were significantly more sensitive to mechanical detection, two-point discrimination, vibration, pin prick as well as cold and warm detection at both the NAC and chest as compared to female chests (p<0.05). Females had significantly lower sensory thresholds to heat pain and pressure pain detection at both the NAC and chest as compared to males (p<0.05).

CONCLUSION

The quantitative sensory functions of female and male chests are significantly different. This knowledge helps to better understand baseline sensory functions at the chest and the awareness of gender differences in this anatomic area.

The prediction of the analgesic placebo response is moderated by outward-focused attention: A sham, randomized clinical trial of chronic back pain patients

The within-subject variability (WSV) of pain-intensity reports has gained attention as a predictor of the placebo response but has demonstrated mixed results. We hypothesized that participants' inward- and outward-directed attention will moderate WSV's prediction of the analgesic placebo response. In this sham randomized clinical trial (protocol number NCT05994118); placebo response was induced in chronic back-pain patients (n=113) through a saline injection plus verbal suggestion. The WSV assessed by the focused analgesia selection test (FAST) served as a predictor. The revised Self-Consciousness Scale (SCS-R), evaluating a person's tendency to focus attention inward or outward was used to moderate the prediction. The placebo response prediction was significantly moderated by 2 SCS-R subscales: public self-consciousness (b = 46.36, SE = 23.08, t = 2.0, p = 0.047) and social anxiety (b = 44.01, SE = 18.02, t = 2.44, p = 0.016). The prediction was significant at low levels of both moderators (p < 0.01), but not at high levels of these traits. Prediction of the placebo response is of value and could promote personalized medical care. Better understanding of factors shaping the placebo response could further contribute to both clinical practice and clinical trials. PERSPECTIVE: The current study demonstrates that the prediction of the analgesic placebo response could be improved if relevant personal characteristics are included as moderators of the prediction. Better predictions of the placebo response could contribute to improve both clinical research and clinical care.

Preoperative Cervical Epidural Steroid Injections: Utilization and Postoperative Complications in ACDF, PCDF, and Decompression

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

Identify factors associated with cervical epidural steroid injection (CESI) receipt before anterior cervical discectomy and fusion (ACDF), posterior cervical decompression and fusion (PCDF), or decompression; evaluate the association between CESI receipt and 90-day postoperative complications; and determine characteristics of CESI associated with complications.

SUMMARY OF BACKGROUND DATA

Previous literature has suggested that a preoperative CESI may increase the risk of postoperative complications. However, these studies were limited in the procedures and complications they evaluated.

METHODS

The IBM MarketScan database was queried for patients aged 18 years or older who underwent ACDF, PCDF, or cervical decompression for disc herniation, stenosis, radiculopathy, myelopathy, and/or spondylosis without myelopathy between January 1, 2014 and September 30, 2020. CESI receipt within 12 months preoperatively, injection characteristics, and postoperative complications were extracted. Multivariable logistic regression models were used to investigate associations between patient characteristics and receipt of CESI, receipt of a CESI and each 90-day postoperative complication, and CESI characteristics and each 90-day complication.

RESULTS

Among the unique patients who underwent each procedure, 20,371 ACDF patients (30.93%), 1259 (22.24%) PCDF patients, and 3349 (36.30%) decompression patients received a preoperative CESI. In all 3 cohorts, increasing age, increasing comorbidity burden, smoker status, and diagnosis of myelopathy were associated with decreased odds of preoperative CESI receipt, while female sex and diagnosis of radiculopathy and spondylosis without myelopathy were associated with increased odds. There were no meaningful between-group comparisons or significant associations between preoperative CESI receipt and any 90-day postoperative complications in multivariable models (all P >0.05).

CONCLUSIONS

This study elucidated the main determinants of CESI receipt and found no differences in the odds of developing 90-day postoperative complications, but did identify differential outcomes with regard to some injection characteristics.

LEVEL OF EVIDENCE

Level III.

Lipid Lowering Therapy Utilization and Lipid Goal Attainment in Women

PURPOSE OF REVIEW

The purpose of this review is to provide an overview of the current status of lipid-lowering therapy utilization and lipid goal attainment in women. We focus on lipid-lowering therapy in individuals with and without established atherosclerotic cardiovascular disease, as well as familial hypercholesterolemia. Additionally, this review aims to explore the underlying mechanisms driving these sex differences and to identify existing knowledge gaps in this area.

RECENT FINDINGS

Despite the proven efficacy of lipid-lowering therapy in both sexes, real-world studies indicate that women with comparable risk profiles are less likely than men to receive these treatments. Furthermore, women who are prescribed statins typically receive lower-intensity regimens than men and are less likely to achieve guideline-recommended low-density lipoprotein cholesterol goals. Despite advancements in lipid-lowering therapies, women compared to men, are systematically undertreated. This difference is influenced by patient-related, physician-related, and societal factors.

The incidence of inflow and drain pain and associated risk factors for patients on peritoneal dialysis

BACKGROUND

The high prevalence and prolonged duration of inflow pain and drain pain experienced by peritoneal dialysis (PD) patients following PD catheter implantation impact their quality of life. However, there is limited data on the frequency and predisposing factors of these pains in the Chinese population undergoing peritoneal dialysis.

METHODS

This study encompassed individuals who underwent peritoneal dialysis catheter implantation at our institution from September 1, 2023, to March 31, 2024. Patients' experiences of inflow pain and drain pain were evaluated using a questionnaire survey and the visual analog scale (VAS), with pain status followed up via telephone for 3 months post-surgery.

RESULTS

A total of 141 patients were included in this study. Inflow pain occurred at rates of 56.0%, 20.9%, 16.9%, and 17.3% at 1-week, 1-month, 2-month, and 3-month postoperatively, respectively, while drain pain rates were 51.8%, 24.3%, 22.3%, and 19.5% for the same period. Slowing down the infusion rate of dialysate (57.0%) or stopping its drainage (60.3%) proved effective in reducing pain. Logistic regression analysis revealed that age (OR = 0.96, P = 0.02), gender (OR = 0.37, P = 0.03), and the method of PD catheter implantation (OR = 2.37, P = 0.04) were independent factors associated with inflow or drain pain within 1-week postoperatively.

CONCLUSION

The occurrence of inflow pain and drain pain following peritoneal dialysis catheter implantation is notable. Age, gender, and the method of catheter implantation were identified as independent factors influencing the incidence of inflow or drain pain within the first postoperative week.

Development and validation of a prediction model for chronic post-surgical pain risk: a single-center prospective study of video-assisted thoracoscopic lung cancer surgery

BACKGROUND

Chronic post-surgical pain (CPSP) is a common complication following video-assisted thoracoscopic surgery (VATS) that significantly impacts the quality of life of patients. Although multiple risk factors have been identified, no systematically validated prediction model exists to guide clinical decision-making.

OBJECTIVES

This study aimed to develop and validate a risk prediction model for CPSP in patients undergoing VATS for lung cancer.

METHODS

This prospective cohort study included clinical data from 400 patients with non-small cell lung cancer who underwent VATS from June 2022 to June 2023. Patients were randomly assigned to a training cohort and an internal test cohort and assessed for sleep quality, psychological status, and pain levels. A nomogram prediction model was established based on variables significantly associated with CPSP in the training cohort. The model was internally validated in the internal test cohort to evaluate its discrimination, calibration, and clinical utility.

RESULTS

Independent risk factors for CPSP included female gender, severe acute pain post-surgery, lymph node dissection, and cold pain sensation, while paravertebral nerve block was identified as a protective factor. The AUC values were 0.878 in training cohort and 0.805 in internal test cohort, respectively, indicating that the model performed well in identifying patients at risk for CPSP. The calibration curves in both cohorts showed a good fit, indicating that the model's predictions were reliable. And the DCA curve showed that using our model to guide decisions resulted in a higher net benefit compared to a strategy of not screening or treating all patients.

CONCLUSION

An effective risk prediction model for CPSP was successfully developed and validated in this study. This model can aid physicians in conducting more accurate assessments of CPSP risk in patients prior to surgery and in offering personalized strategies for managing CPSP.

CLINICAL REGISTRATION NUMBER

Registration website: https://www.chictr.org.cn/ . Registration date: 2022/5/21.

REGISTRATION NUMBER

ChiCTR2200060196.

Gene Expression Correlates with Disability and Pain Intensity in Patients with Chronic Low Back Pain and Modic Changes in a Sex-Specific Manner

Chronic low back pain (cLBP) lacks clear physiological explanations, and the treatment options are of limited effect. We aimed to elucidate the underlying biology of cLBP in a subgroup of patients with Modic changes type I (suggestive of inflammatory vertebral bone marrow lesions) by correlating gene expression in blood with patient-reported outcomes on disability and pain intensity and explore sex differences. Patients were included from the placebo group of a clinical study on patients with cLBP and Modic changes. Blood was collected at the time of inclusion, after three months, and after one year, and gene expression was measured at all time points by high-throughput RNA sequencing. The patients reported disability using the Roland-Morris Disability Questionnaire, and pain intensity was assessed as a mean of three scores on a 0-10 numeric rating scale: current LBP, worst LBP within the last two weeks, and mean LBP within the last two weeks. The gene expression profiles were then correlated to the reported outcomes. Changes in gene expression over time correlated significantly with changes in both disability and pain. The findings showed distinct patterns in men and women, with negligible overlap in correlated genes between the sexes. The genes involved were enriched in immunological pathways, particularly T cell receptor complex and immune responses related to neutrophils. Several of the genes harbour polymorphisms that previously have been found to be associated with chronic pain. Taken together, our results indicate gender differences in the underlying biology of disability and pain intensity in patients with low back pain.

Prescription of Strong Opioids in Chronic Non-Cancer Pain in the Province of Valladolid (Spain)

Background: Chronic non-cancer pain (CNCP) is one of the leading causes of disability. The use of strong opioids (SOs) in the management of CNCP is increasing, although evidence supporting their use remains limited. Primary care (PC) plays a key role in this context. Objectives: Our objectives were to determine the prevalence and profile of patients using SOs for CNCP in PC consultations in Valladolid in 2022, and to describe the consumption of SO prescribed for CNCP from 2020 to 2023. Methods: We conducted a descriptive and retrospective study using data extracted from the Pharmaceutical Consumption Information System of Castilla y León. Patients in Valladolid with SO use for more than three months due to CNCP were analyzed. Sociodemographic and clinical characteristics of these patients in 2022 were described. The number of defined daily doses (nº DDDs) and costs from 2020 to 2023 were analyzed. Results: A total of 3642 patients were included (0.7% of the population of Valladolid), 71.8% of whom were women. Of the patients, 62.4% were aged 70 or older, 39.8% lived in rural areas, and 9.9% resided in nursing homes. The most frequently prescribed SOs in nº DDDs were fentanyl and tapentadol. The highest consumption in nº DDDs was in patients who lived in nursing homes, were over 70 years old and were resident in rural areas. The number of DDDs from 2020 to 2023 for SOs in DCNO increased by 41%. Conclusions: In total, 0.7% of the population of Valladolid consumes SOs for CNCP, mostly women and people over 70 years old. The consumption of strong opioids in DDDs grew by 41% from 2020 to 2023.

Sex-specific differences in insulin response and substrate oxidation after repeated, brief whole-body immersion in 45 °C water: A prospective, interventional study

Prolonged heat exposure is suggested to improve glucose metabolism and fat oxidation, but no studies have addressed whether brief heat stimuli represent a viable, time-efficient, alternative approach. Consequently, we examined the ability of brief stimuli evoked by 45 °C water to improve glucose tolerance, insulin sensitivity, and fat oxidation in young, non-obese, males and females. Twenty-four participants completed fourteen 5-min sessions involving whole body passive heating in 45 °C water. Changes in resting catecholamines, cytokines, substrate oxidation, resting energy expenditure, glucose tolerance, and insulin release in response to an oral glucose tolerance test, were assessed before and 24-h after intervention, and 1 month after the end of the intervention. The results showed that repeated short-duration heat intervention had no significant effects on epinephrine, norepinephrine, interleukin-6, and tumor necrosis factor alpha production in both sexes. Glucose area under the curve (AUC) was not affected. However, females had a lower insulin AUC and improved insulin sensitivity as indicated by a decrease in homeostatic model assessment for insulin resistance, and an increase in the quantitative insulin sensitivity check index and the Matsuda insulin sensitivity index values one month after the end of the heat intervention. No effect was observed in resting energy expenditure, but carbohydrate oxidation per kilogram increased in females, and this substrate oxidation change was maintained after one month. In conclusion, fourteen sessions of brief 5-min whole-body immersion in 45 °C water produced an improvement in insulin sensitivity and increased reliance on carbohydrate oxidation in females.

Characterizing pain in Parkinson's disease: types, predictors, and management implications

Background

Pain impacts quality of life (QoL) in Parkinson's disease (PD) patients, yet it is often overlooked. This study aims to comprehensively evaluate pain in PD, particularly focusing on differences between neuropathic pain (NP) and other types.

Methods

We conducted a cross-sectional study involving PD patients, assessing the prevalence and characteristics of pain. Various scales were employed to evaluate anxiety, depression, and QoL. We investigated associations between pain, demographic, and clinical variables to determine predictors and pain-related factors. Additionally, factors related to NP were explored.

Results

During the study period, a total of 109 patients were examined. Sixteen patients were excluded due to various reasons. The final analysis included 93 patients (34 females and 59 males). Pain was reported by 80.6% of PD patients, with no significant demographic or clinical differences between those with and without pain. However, longer disease duration predicted NP, and musculoskeletal pain was more prevalent in females. Anxiety was common in patients with central parkinsonian pain (CPP). Patients taking amantadine reported less radicular/ neuropathic pain (RNP), suggesting a therapeutic role.

Conclusions

Our findings underscore the high prevalence of pain in PD and its impact on QoL. NP appears to be associated with disease progression, while sex-specific differences highlight the need for personalized pain management strategies. The association between anxiety and CPP emphasizes the importance of addressing psychological factors in PD pain management. Further research on amantadine's benefits in reducing RNP is warranted, emphasizing the importance of tailored pain management strategies for PD patients.

Mental burden of ocular surface discomfort

OBJECTIVE

This research investigates the associations between Dry Eye Disease (DED), pain perception, and mental health, focusing on how neuropathic pain influences treatment efficacy and patients' quality of life.

METHODS AND RESULTS

The study delves into the complexity of DED by assessing the correlation between ocular pain, depression, PTSD, and systemic pain conditions. It highlights the role of chronic neuropathic pain in DED and the nociceptive hypothesis, which suggests that psychological stress can exacerbate DED symptoms. Additionally, it explores diagnostic and management strategies for DED, emphasizing the importance of considering psychological aspects to improve patient care.

CONCLUSIONS

The intricate nature of DED, closely linked to mental health issues, requires a comprehensive diagnostic and therapeutic approach. Addressing neuropathic pain and psychological factors is crucial for effective DED management. Future efforts should focus on developing specific interventions targeting DED's physical and emotional impacts to enhance overall patient well-being.

The Association Between Pain and Physical Frailty Among Older Adults in India: Depression and Insomnia as Mediators

OBJECTIVES

To investigate the association between body pain and physical frailty among older adults in India and to examine whether this association is mediated by symptoms of depression and insomnia.

METHODS

Data were obtained from the Longitudinal Aging Study in India, comprising 31,464 adults aged 60 and older. Physical frailty was assessed using a modified version of the frailty phenotype developed by Fried and colleagues. Multivariable logistic regression was used to analyze associations, and the Karlson-Holm-Breen method was employed to evaluate mediation effects.

RESULTS

The prevalence of frailty was 30.65%, with women showing a higher prevalence than men (33.16% vs. 27.85%). Older adults experiencing body pain had increased odds of frailty (adjusted odds ratio [aOR]: 1.17, 95% CI: 1.06-1.35). Depression (aOR: 1.70, 95% CI: 1.44-2.01) and insomnia symptoms (aOR: 1.58, 95% CI: 1.38-1.81) were independently associated with higher odds of frailty. Mediation analysis showed that depression mediated 8.4% of the association between pain and frailty in men and 6.11% in women. Insomnia symptoms mediated 11.47% of the association in men and 14.54% in women.

CONCLUSION

Body pain was significantly associated with a higher likelihood of frailty among older adults in India. Symptoms of depression and insomnia partially mediated this association, with a stronger mediating effect observed for insomnia in women. Inclusive health care strategies addressing pain, depression, and insomnia could help mitigate the risk of frailty in this population.

Peritraumatic C-reactive protein levels predict pain outcomes following traumatic stress exposure in a sex-dependent manner

Background

Chronic pain following traumatic stress exposure (TSE) is common. Increasing evidence suggests inflammatory/immune mechanisms are induced by TSE, play a key role in the recovery process versus development of post-TSE chronic pain, and are sex specific. In this study, we tested the hypothesis that the inflammatory marker C-reactive protein (CRP) is associated with chronic pain after TSE in a sex-specific manner.

Methods

We utilized blood-plasma samples and pain questionnaire data from men (n=99) and (n=223) women enrolled in AURORA, a multi-site emergency department (ED)-based longitudinal study of TSE survivors. We measured CRP using Ella/ELISA from plasma samples collected in the ED ('peritraumatic CRP', n=322) and six months following TSE (n=322). Repeated measures mixed-effects models were used to assess the relationship between peritraumatic CRP and post-TSE chronic pain.

Results

Peritraumatic CRP levels significantly predicted post-TSE chronic pain, such that higher levels of CRP were associated with lower levels of pain over time following TSE, but only in men (men:β=-0.24, p=0.037; women:β=0.05, p=0.470). By six months, circulating CRP levels had decreased by more than half in men, but maintained similar levels in women (t(290)=1.926, p=0.055). More men with a decrease in CRP levels had decreasing pain over time versus women (men:83% women:65%; Z=2.21, p=0.027).

Conclusions

In men but not women, we found circulating peritraumatic CRP levels predict chronic pain outcomes following TSE and resolution of CRP levels in men over time might be associated with increased pain recovery. Further studies are needed to validate these results.

Same patient but different worlds: A state-of-the-art review translating best practice psychosocial care from musculoskeletal care to the orthopaedic context

BACKGROUND

Individuals with chronic musculoskeletal conditions experience persistent pain and disability that has deleterious impacts on physical function, psychological health, social engagement, relationships, and work participation. This impact is greater in people with psychosocial risk factors, and best practice musculoskeletal care recommends a biopsychosocial approach to management. Orthopaedic surgery is often an effective management approach for chronic musculoskeletal conditions, but research has only recently explored the links between differing patient outcomes after orthopaedic surgery and psychosocial risk factors. Implementing biopsychosocial approaches to musculoskeletal care has taken great strides in the primary care setting however, implementation of the biopsychosocial approach in orthopaedic surgery brings complexity as the context changes from primary care to hospital based secondary care. The aim of this review therefore is to explore implementation of psychosocial care in the elective orthopaedic surgery context, informed by evidence in musculoskeletal care.

ASSESSMENT AND MANAGEMENT OF PSYCHOSOCIAL FACTORS

Several composite screening tools for psychosocial factors or 'yellow flags' are recommended for use in primary care for musculoskeletal conditions alongside a comprehensive patient interview. However, in the orthopaedic surgery context, composite measures have focused on discharge destination, and there is not a universal approach to comprehensive patient interview incorporating a biopsychosocial approach. A range of biopsychosocial approaches to musculoskeletal conditions have been developed for the primary care setting, yet few have been explored in the context of orthopaedic surgery.

IMPLEMENTATION OF PSYCHOSOCIAL CARE

Implementing best practice psychosocial care into the orthopaedic context has enormous potential for all stakeholders, but several barriers exist at the level of the individual patient and practitioner, workforce, health service and society. We have discussed key considerations for implementation including workforce composition, patient-centred care and shared decision making, health literacy, continuity of care, and consideration of preferences for women and culturally diverse communities.

CONCLUSION

This review considers current literature exploring implementation of psychosocial care into the orthopaedic surgery context, informed by current research in musculoskeletal care. This presents a critical opportunity for orthopaedic surgery to provide optimised, equitable, high-value, patient-centred care.