Conceptual complexity of gender and its relevance to pain

Associations of Gender Role and Pain in Musculoskeletal Disorders: A Mixed-Methods Systematic Review

Previous studies have investigated the association of gender roles with pain outcomes in healthy individuals. However, little is known about this association in those with musculoskeletal (MSK) disorders. Therefore, this mixed-methods systematic review aimed to investigate the association of sociocultural gender roles on pain outcomes in adults with MSK disorders. Literature from Medline, CINAHL, Web of Science, and Embase was reviewed from inception to February 2023. Eligibility criteria included studies of adults with an MSK pain disorder that explored the relationship between gender roles and pain for all primary qualitative and quantitative study designs. Exclusion criteria were gray literature, review articles, case studies, and conference proceedings. Risk of bias was assessed via the Quality Appraisal for Diverse Studies for quantitative studies and the McMaster Quality Appraisal Tool for qualitative studies. Eleven studies were included, 9 qualitative, and 2 quantitative with a total of 540 participants (19.6% women, 80.4% men) with various MSK disorders. The convergent integrated approach was used to synthesize data from the qualitative and quantitative studies resulting in 3 themes and 7 subthemes. Our findings identified differences in the way individuals explained the cause of their pain, were treated for their pain in a social and systemic context, and in describing the effect pain had on their lives based on gender roles. There is a need for pain management to evolve to acknowledge the individual pain experience through exploration of an individual's gender identity and roles. PERSPECTIVE: This article demonstrates that gender roles have a multidimensional influence on the pain experience in those with MSK disorders. These findings support the development of gender-sensitive, patient-centered approaches to pain management, acknowledging each individual's important roles and identities.

Developing a gender measure and examining its association with cardiovascular diseases incidence: a 28-year prospective cohort study

BACKGROUND

Cardiovascular diseases (CVD) are the leading cause of morbidity and mortality worldwide. Examining gender (socio-cultural) in addition to sex (biological) is required to untangle socio-cultural characteristics contributing to inequities within or between sexes. This study aimed to develop a gender measure including four gender dimensions and examine the association between this gender measure and CVD incidence, across sexes.

METHODS

A cohort of 9188 white-collar workers (49.9% females) in the Quebec region was recruited in 1991-1993 and follow-up was carried out 28 years later for CVD incidence. Data collection involved a self-administered questionnaire and extraction of medical-administrative CVD incident cases. Cox proportional models allowed calculations of hazard ratios (HR) and 95% confidence intervals (CI), stratified by sex.

RESULTS

Sex and gender were partly independent, as discordances were observed in the distribution of the gender score across sexes. Among males, being in the third tertile of the gender score (indicating a higher level of characteristics traditionally ascribed to women) was associated with a 50% CVD risk increase compared to those in the first tertile (HR = 1.50; 95% CI: 1.24 to 1.82). This association persisted after adjustment for several CVD risk factors (HR = 1.42; 95% CI: 1.16 to 1.73). Conversely, no statistically significant association between the third tertile of the gender score and CVD incidence was observed in females (HR = 0.79, 95% CI: 0.60-1.05).

CONCLUSIONS

The findings suggested that males within the third tertile of the gender score were more likely to develop CVD, while females with those characteristics did not exhibit an increased risk. These findings underline the necessity for clinical and population health research to integrate both sex and gender measures, to further evaluate disparities in cardiovascular health and enhance the inclusivity of prevention strategies.

The prevalence of chronic pain in children and adolescents: a systematic review update and meta-analysis

ABSTRACT

Chronic pain, defined as persistent or recurring pain or pain lasting longer than 3 months, is a common childhood problem. The objective of this study was to conduct an updated systematic review and meta-analysis on the prevalence of chronic pain (ie, overall, headache, abdominal pain, back pain, musculoskeletal pain, multisite/general pain, and other) in children and adolescents. EMBASE, PubMed, CINAHL, and PsycINFO were searched for publications between January 1, 2009, and June 30, 2023. Studies reporting population-based estimates of chronic nondisease related pain prevalence in children or adolescents (age ≤ 19 years) were included. Two independent reviewers screened articles based on a priori protocol. One hundred nineteen studies with a total of 1,043,878 children (52.0% female, mean age 13.4 years [SD 2.4]) were included. Seventy different countries were represented, with the highest number of data points of prevalence estimates coming from Finland and Germany (n = 19 each, 4.3%). The overall prevalence of chronic pain in children and adolescents was 20.8%, with the highest prevalence for headache and musculoskeletal pain (25.7%). Overall, and for all types of pain except for back pain and musculoskeletal pain, there were significant differences in the prevalence between boys and girls, with girls having a higher prevalence of pain. There was high heterogeneity (I 2 99.9%). Overall risk of bias was low to moderate. In summary, approximately 1 in 5 children and adolescents experience chronic pain and prevalence varies by pain type; for most types, there is higher pain prevalence among girls than among boys. Findings echo and expand upon the systematic review conducted in 2011.

Social Determinants and Consequences of Pain: Toward Multilevel, Intersectional, and Life Course Perspectives

Despite wide endorsement of a biopsychosocial framework for pain, social aspects of pain remain rarely addressed in the context of pain prevention and management. In this review, we aim to 1) examine the broad scope of social determinants and consequences of pain and their interactions across multiple levels of organization, and 2) provide a framework synthesizing existing concepts and potential areas for future work on social aspects of pain, drawing upon socioecological, intersectional, and life course approaches. Integrating interdisciplinary theory and evidence, we outline pathways through which multilevel social factors and pain may affect each other over time. We also provide a brief summary of intrapersonal aspects of pain, which are thought to operate at the interface between individuals and the social context. Progressing from micro- to macrolevel factors, we illustrate how social determinants of pain can directly or indirectly contribute to pain experiences, expression, risk, prognosis, and impact across populations. We consider 1) at the interpersonal level, the roles of social comparison, social relatedness, social support, social exclusion, empathy, and interpersonal conflict; 2) at the group or community level, the roles of intimacy groups, task groups, social categories, and loose associations; and 3) at the societal level, the roles of political, economic, and cultural systems, as well as their policies and practices. We present examples of multilevel consequences of pain across these levels and discuss opportunities to reduce the burden and inequities of pain by expanding multilevel social approaches in pain research and practice. PERSPECTIVE: Despite wide endorsement of a biopsychosocial framework for pain, social aspects of pain are often unclearly defined, hindering their use in pain prevention, management, and research. We summarize the scope of social aspects of pain and provide a framework synthesizing existing concepts and potential areas for future work.

Understanding Risk of Chronic Pain Development and Related Mental Health Disparities Among Transgender People: A Review of Current Literature and Future Directions

Biomedical and clinical research has traditionally focused on binary sex assignments as opposed to gender identity. This oversight has resulted in other gender minority populations being understudied. As a result, there is limited literature on chronic pain and mental health in transgender populations. These socially vulnerable individuals may be at increased risk for chronic pain development and related mental health disorders. Transgender individuals experience higher rates of social stigma and discrimination than their cisgender counterparts, and these factors have been linked to an increased prevalence of chronic pain, depression, and stress. Beyond chronic pain and mental health research, large overall health disparities and differences exist for transgender people compared with their cisgender peers. Therefore, it is crucial to include transgender individuals, as well as other gender minority people, in research in order to fully understand the impact of gender minority status on pain and quality of life. PERSPECTIVE: This review explores the intersectional impact of stress and mental health on chronic pain development and the unequal risk for transgender individuals. Promoting inclusion of gender minority individuals in research is a critical step to understanding the factors contributing to minority stress.

Gender Diversity Among Youth Attending an Intensive Interdisciplinary Pain Treatment Program

Transgender and gender diverse (TGD) youth with chronic pain may be at unique risk for psychological distress and associated functional impairment, yet research on the intersection of chronic pain and gender identity is lacking. In a retrospective chart review of 491 participants admitted to a pediatric intensive interdisciplinary pain treatment (IIPT) program in the midwestern United States over an approximately 4-year period, 6.11% were TGD. TGD participants who completed the IIPT program reported significant and large improvements in anxiety, depression, pain catastrophizing, and functional ability. At baseline, TGD participants presented as more emotionally distressed and functionally impaired compared to age-matched, cisgender peers. When accounting for baseline scores, TGD participants who completed the IIPT program reported similar scores to cisgender peers at discharge, yet TGD youth were significantly less likely than cisgender peers to complete the IIPT program. Future directions and implications for clinical practice are discussed.

Sex differences in mechanisms of pain hypersensitivity

The introduction of sex-as-a-biological-variable policies at funding agencies around the world has led to an explosion of very recent observations of sex differences in the biology underlying pain. This review considers evidence of sexually dimorphic mechanisms mediating pain hypersensitivity, derived from modern assays of persistent pain in rodent animal models. Three well-studied findings are described in detail: the male-specific role of spinal cord microglia, the female-specific role of calcitonin gene-related peptide (CGRP), and the female-specific role of prolactin and its receptor. Other findings of sex-specific molecular involvement in pain are subjected to pathway analyses and reveal at least one novel hypothesis: that females may preferentially use Th1 and males Th2 T cell activity to mediate chronic pain.

How are sex-gender differences in chair-and-desk-based postural variability explained? A scoping review

BACKGROUND

Desk-work-related musculoskeletal pain is more prevalent among female workers than male workers. This may be contributed to by sex and/or gender differences in postural variability however, the mechanisms underpinning these differences are poorly understood. This review investigates whether desk-based postural variability studies investigate sex-gender differences and, how they explain the mechanisms behind these differences.

METHODS

A scoping review was conducted with four databases (PubMed, Embase, Scopus and ProQuest) searched in June and July 2023. Studies investigating postural variability among desk-based workers were included and a narrative approach used to synthesise results.

RESULTS

15 studies were included. Only four reported on sex-gender differences. None collected psychological or social information to explore reasons for sex-gender differences.

CONCLUSION

The mechanisms behind postural variability differences between sexes and genders are complex and multifactorial. Studies largely do not consider sex and gender and do not collect the information necessary to explain their results.

A developmental framework for understanding the influence of sex and gender on health: Pediatric pain as an exemplar

Sex differences are a robust finding in many areas of adult health, including cardiovascular disease, psychiatric disorders, and chronic pain. However, many sex differences are not consistently observed until after the onset of puberty. This has led to the hypothesis that hormones are primary contributors to sex differences in health outcomes, largely ignoring the relative contributions of early developmental influences, emerging psychosocial factors, gender, and the interaction between these variables. In this paper, we argue that a comprehensive understanding of sex and gender contributions to health outcomes should start as early as conception and take an iterative biopsychosocial-developmental perspective that considers intersecting social positions. We present a conceptual framework, informed by a review of the literature in basic, clinical, and social science that captures how critical developmental stages for both sex and gender can affect children's health and longer-term outcomes. The literature on pediatric chronic pain is used as a worked example of how the framework can be applied to understanding different chronic conditions.

Changing society, changing research: integrating gender to better understand physical and psychological treatments use in chronic pain management

ABSTRACT

Treatment of chronic pain should be multimodal and include pharmacological, physical, and psychological treatments. However, because various barriers to physical and psychological treatments (PPTs) exist, a better understanding of biopsychosocial factors leading to their use is relevant. This study aimed to explore the association between gender identity, gender-stereotyped personality traits, and the use of PPTs in chronic pain management. The ChrOnic Pain trEatment cohort, a self-reported data infrastructure resulting from a web-based recruitment of 1935 people living with chronic pain (Quebec, Canada) was analyzed. Gender identity was operationalized as women, men, and nonbinary. Gender-stereotyped personality traits were measured using the Bem Sex-Role Inventory (feminine, masculine, androgynous, undifferentiated). A checklist of 31 types of PPTs that can be used for chronic pain management was presented to participants (yes/no). From the 1433 participants, 85.5% reported using at least one PPT. Hot-cold therapies (43.4%), exercise (41.9%), and meditation (35.2%) were the most frequently used PPTs, but most popular PPTs were not the same among women and men. Women reported a significantly higher use of PPTs in general (87.2% vs 77.2%; P < 0.001). Multivariable and interaction analyses showed that identifying as a man decreased the odds of reporting the use of PPTs (odds ratio: 0.32, 95% confidence interval: 0.11-0.92) but only among participants who scored high on both masculine and feminine personality traits (those classified as androgynous). The high prevalence of PPTs use found in our study is positive. Our results are relevant for a more personalized promotion of PPTs for chronic pain management.

Challenges with embedding an integrated sex and gender perspective into pain research: Recommendations and opportunities

The focus of this article, within this BBI horizons special issue, is on sex, gender, and pain. We summarise what is currently known about sex- and gender-related variations in pain, exploring intersectional biological and psychosocial mechanisms, and highlight gaps in knowledge and understanding. Five key challenges with the exploration of sex and gender in pain research are presented, relating to: conceptual imprecision, research bias, limitations with binary descriptions, integrating sex and gender, and timely adoption/implementation of good research practice. Guidance on how to overcome such challenges is provided. Despite clear evidence for sex and gender differences in pain, there are conceptual and methodological barriers to overcome. Innovation in methods and approach can help develop more effective and tailored treatment approaches for men, women, boys, girls, and gender-diverse people.

Sex and Age-at-Injury as Determinants of Social Behavior Outcomes After TBI

While our understanding of long-term disability after traumatic brain injury (TBI) has habitually focused on cognitive and sensorimotor functioning, it is increasingly appreciated that changes in social function for survivors of a brain injury are common and have a profound impact on one's quality of life. In this chapter, we highlight the consequences of TBI on social behavior, taking into account evidence from studies of patient populations as well as from preclinical animal models. After first considering the protracted nature of the development of social behavior across the lifespan, including the neurobiological networks that underlie social functioning, we discuss how TBI results in social behavior impairments and how these manifest. We focus particularly on how age-at-injury influences TBI-induced social impairments, with most of the evidence suggesting age-dependent vulnerability after injury at a younger age. In addition, we explore how biological sex is a key determinant of social behavior impairments after TBI, while gender in humans may also influence the nature and extent of social outcomes. Finally, we identify key knowledge gaps and emphasize the need for further research in the field.

Expectations of treatment outcome in complex cases of patients with chronic pain: A study on the DATAPAIN cohort

BACKGROUND

A better insight in how the biopsychosocial factors influence patient outcome(s) may provide information that helps selecting the optimal pain management for a specific group.

METHODS

Categorization was made in the prospective DATAPAIN registry, in which patients with pain severity (Numeric Rating Scale [NRS]: 7-10), depression or anxiety (Hospital Anxiety and Depression Scale: > 10), and pain catastrophizing (Pain Catastrophizing Scale: > 31) were identified as complex cases. Patient outcomes; treatment satisfaction on the Patient Global Impression of Change (PGIC), pain relief (NRS), pain interference on the Brief Pain Inventory (BPI) and quality of life indicator General Perceived Health (GPH) were evaluated. Logistic regression analyzed if belonging to the complex cases showed modification in the outcome of the PGIC and GPH. Linear regression was observed if complex cases differed in average reduction in pain relief and interference compared to non-complex cases.

RESULTS

1637 patients were included, of which 345 (21.08%) were considered complex cases. The changes in scores of pain relief and BPI active subscale were not significantly different between groups. The BPI affective subscale had a different change in score (-0.509; p: 0.002). The complex cases had an odds ratio (OR) of 0.59 (95% confidence interval [CI]: 0.36-0.77) on treatment satisfaction compared to non-complex cases, and an OR of 0.28 (95% CI: 0.11-0.56) on the GPH.

CONCLUSION

When treating patients with complex cases, desired treatment outcome(s) should be recognized by specialists and patients, as these may be less likely to occur.

Effectiveness of Self-Care Education for Chronic Neck Pain: A Systematic Review and Meta-Analysis

Self-care programs for chronic neck pain are relevant to everyday life and can lead to long- term improvement. More studies on their effectiveness, key components and appropriate duration are needed. The aim of this study was to determine the effectiveness of self-care programs for patients with chronic neck pain. A systematic review and meta-analysis of randomized controlled trials was conducted according to the PRISMA guidelines. After searching in PubMed, Web of Science, Scopus and ScienceDirect, eleven studies met the inclusion criteria. Self-care education interventions typically consisted of education (i.e., pain neuro-science education or general educational concepts) accompanied by exercise or manual therapy. The most frequent components were addressing physical and psychological symptoms and engaging in self-care strategies. The least frequent ones were monitoring and recording symptoms and discussing with providers of medical care. The duration of the interventions ranged from three sessions to six months. Finally, individual and supervised modalities were the most frequent. After pooling the data, a meta-analysis was carried out according to four variables (i.e., pain, disability, kinesiophobia and catastrophization) and showed significant results (p < 0.05) in favor of self-care interventions. This systematic review and meta-analysis suggests that self-education interventions improve pain, psychological pain-related variables and disability in patients with chronic neck pain. The most frequently used components were addressing physical and psychological symptoms and engaging in self-care strategies. Future trials should focus on including other components, such as discussing symptoms with providers of medical care or self-monitoring symptoms. Additional areas of focus include more homogeneous doses and comparator treatments, as well as studies with better evidence to reach more solid conclusions.

Gender-based differences in assessment and management of acute abdominal pain in the emergency department: A retrospective audit

BACKGROUND

Previous research has identified gender-based differences in acute pain management in the emergency department [ED]. The aim of this study was to compare pharmacological management of acute abdominal pain in the ED by gender.

METHODS

A retrospective chart audit was conducted at one private metropolitan ED including adult patients (18-80 years) who presented with acute abdominal pain in 2019. Exclusion criteria included: pregnancy, repeat presentation within the study period, pain-free at initial medical review or documented refusal of analgesia, and oligo-analgesia. Comparisons by gender included: (1) analgesia type and (2) time to analgesia. Bivariate analysis was undertaken using SPSS.

RESULTS

There were 192 participants: 61 (31.6 %) men and 131 (67.9 %) women. Men were more likely to get combined opioid and non-opioid medication as first line analgesia (men: 26.2 % n = 16; women: 14.5 % n = 19, p = .049). Median time from ED presentation to analgesia was 80 min for men (IQR: 60) versus 94 min for women (IQR: 58), (p = .119). Women (25.2 % n = 33) were more likely to receive their first analgesic after 90 min from ED presentation compared to men versus men (11.5 %, n = 7 p = .029). In addition, women waited longer before receiving second analgesia (women: 94, men: 30 min, p = .032).

CONCLUSION

Findings confirm there are differences in pharmacological management of acute abdominal pain in the ED. Larger studies are required to further explore differences observed in this study.

Sex and gender differences in healthcare utilisation trajectories: a cohort study among Quebec workers living with chronic pain

OBJECTIVES

Chronic pain (CP) is a poorly recognised and frequently inadequately treated condition affecting one in five adults. Reflecting on sociodemographic disparities as barriers to CP care in Canada was recently established as a federal priority. The objective of this study was to assess sex and gender differences in healthcare utilisation trajectories among workers living with CP.

DESIGN

Retrospective cohort study.

PARTICIPANTS

This study was conducted using the TorSaDE Cohort which links the 2007-2016 Canadian Community Health Surveys and Quebec administrative databases (longitudinal claims). Among 2955 workers living with CP, the annual number of healthcare contacts was computed during the 3 years after survey completion.

OUTCOME

Group-based trajectory modelling was used to identify subgroups of individuals with similar patterns of healthcare utilisation over time (healthcare utilisation trajectories).

RESULTS

Across the study population, three distinct 3-year healthcare utilisation trajectories were found: (1) low healthcare users (59.9%), (2) moderate healthcare users (33.6%) and (3) heavy healthcare users (6.4%). Sex and gender differences were found in the number of distinct trajectories and the stability of the number of healthcare contacts over time. Multivariable analysis revealed that independent of other sociodemographic characteristics and severity of health condition, sex-but not gender-was associated with the heavy healthcare utilisation longitudinal trajectory (with females showing a greater likelihood; OR 2.6, 95% CI 1.6 to 4.1).

CONCLUSIONS

Our results underline the importance of assessing sex-based disparities in help-seeking behaviours, access to healthcare and resource utilisation among persons living with CP.

A genderful research world: rapid review, design, and pilot study of an interactive platform for curated sex and gender health research resources

BACKGROUND

Integration of sex and gender into health research is best practice for designing and conducting equitable, rigorous scientific research. Many evidence-based resources exist to support researchers in this endeavour, but such resources often remain underutilized as they are difficult to find, are not publicly accessible, or are specific to a particular research phase, context, or population. The development and evaluation of a repository of resources was deemed important to create an accessible platform for promoting sex- and gender-integration in health research.

METHODS

A rapid review was conducted of critical resources for conducting sex and gender health research. These were integrated into a prototype website design (the Genderful Research World; GRW) that provided an interactive digital landscape for researchers to access these resources. A pilot study evaluated the GRW website for applicability, desirability, and usability with an international sample of 31 health researchers from various disciplines and career stages. Quantitative data from the pilot study was summarized with descriptive statistics. Qualitative data was summarized narratively and used to identify concrete elements for improvement in a second design iteration.

RESULTS

Results of the pilot study revealed that the GRW was considered user friendly and desirable by health researchers and helped them access relevant information. Feedback suggested that providing these resources in a playful way may enhance the experience of the user, particularly given the high 'desirability' scores and that users emphasized the interactive layout as being key to their intention to integrate it into their teaching endeavors. Key feedback from the pilot study (e.g., addition of resources specific to research with transgender populations, revision of website layout) was integrated into the current version of the website: www.genderfulresearchworld.com .

CONCLUSIONS

The present research suggests a utility for a repository of resources for integrating sex and gender considerations into research, and that providing a logical, intuitive means of cataloguing and navigating such resources is critical for usability. The results of this study may inform the development of other novel researcher-directed resource curation efforts to address health equity issues and encourage and support health researchers to integrate a sex and gender perspective in their work.

Polygenic Contributions to Chronic Overlapping Pain Conditions in a Large Electronic Health Record Sample

Chronic overlapping pain conditions (COPCs) are believed to share common etiological mechanisms involving central sensitization. Genetic and environmental factors putatively combine to influence susceptibility to central sensitization and COPCs. This study employed a genome-wide polygenic risk score approach to evaluate genetic influences on 8 common COPCs. COPCs were identified by International Classification of Disease codes in Vanderbilt's deidentified clinical biorepository (BioVU), with each COPC condition empirically weighted for the level of central sensitization based on prior work. A centralized pain score (CPS) was calculated for 55,340 individuals by summing the weighted number of COPCs. Overall, 12,502 individuals (22.6%) were diagnosed with at least 1 COPC, with females exhibiting nearly twice the mean CPS as males. To assess the genetic influence on centralized pain in COPCs, 6 pain polygenic risk scores (PRSs) were developed using UK Biobank data to predict 6 pain criteria (no pain, neck/shoulder, abdomen, hip, knee, low back pain). These PRSs were then deployed in the BioVU cohort to test for association with CPS. In regression models adjusted for age, sex, and BMI, all pain PRSs except hip pain were significantly associated with CPS. Our findings support a shared polygenic influence across COPCs potentially involving central sensitization mechanisms. PERSPECTIVE: This study used a polygenic risk score approach to investigate genetic influences on chronic overlapping pain conditions. Significant findings in this study provide evidence supporting previous hypotheses that a shared polygenic influence involving central sensitization may underly chronic overlapping pain conditions and can guide future biomarker and risk assessment research.

Alterations in pain during adolescence and puberty

During adolescence and puberty, alterations in pain, both experimental and clinical, are observed. In addition, adolescents undergo extensive biopsychosocial changes as they transition from childhood to adulthood. However, a better understanding of how the biopsychosocial changes during adolescence impact pain is needed to improve pain management and develop targeted pain interventions for adolescents. This review synthesizes the literature on alterations in pain during adolescence in humans, describes the potential biopsychosocial factors impacting pain during adolescence, and suggests future research directions to advance the understanding of the impact of adolescent development on pain.

Psychosocial resources predict frequent pain differently for men and women: A prospective cohort study

INTRODUCTION

Psychosocial resources, psychological and social factors like self-efficacy and social support have been suggested as important assets for individuals with chronic pain, but the importance of psychosocial resources for the development of pain is sparsely examined, especially sex and gender differences. The aim of this study was to investigate associations between psychosocial resources and sex on the development of frequent pain in a general population sample, and to deepen the knowledge about sex and gender patterns.

METHODS

A sample from the Swedish Health Assets Project, a longitudinal cohort study, included self-reported data from 2263 participants, 53% women, with no frequent pain at baseline. The outcome variable was frequent pain at 18-months follow-up. Psychosocial resources studied were general self-efficacy, instrumental and emotional social support. Log binomial regressions in a generalised linear model were used to calculate risk ratios (RRs), comparing all combinations of men with high psychosocial resources, men with low psychosocial resources, women with high psychosocial resources and women with low psychosocial resources.

RESULTS

Women with low psychosocial resources had higher risk of frequent pain at follow-up compared to men with high resources: general self-efficacy RR 1.82, instrumental social support RR 2.33 and emotional social support RR 1.94. Instrumental social support was the most important protective resource for women, emotional social support was the most important one for men. Results were discussed in terms of gender norms.

CONCLUSIONS

The psychosocial resources general self-efficacy, instrumental and emotional support predicted the risk of developing frequent pain differently among and between men and women in a general population sample. The results showed the importance of studying sex and gender differences in psychological and not least social predictors for pain.

The Geography of Pain in the United States and Canada

Pain epidemiologists have, thus far, devoted scant attention to geospatial analyses of pain.  Both cross-national and, especially, subnational variation in pain have been understudied, even though geographic comparisons could shed light on social factors that increase or mitigate pain. This study presents the first comparative analysis of pain in the U.S. and Canada, comparing the countries in aggregate, while also analyzing variation across states and provinces. Analyses are based on cross-sectional data collected in 2020 from U.S. and Canadian adults 18 years and older (N = 4,113). The focal pain measure is a product of pain frequency and pain interference. We use decomposition and regression analyses to link socioeconomic characteristics and pain, and inverse-distance weighting spatial interpolation to map pain levels. We find significantly and substantially higher pain in the U.S. than in Canada. The difference is partly linked to Americans' worse economic conditions. Additionally, we find significant pain variability within the U.S. and Canada. U.S. states in the Deep South, Appalachia, and parts of the West stand out as pain 'hotspots' with particularly high pain levels. Overall, our findings identify areas with a high need for pain prevention and management; they also urge further scholarship on geographic factors as important covariates in population pain. PERSPECTIVE: This study documents the high pain burden in the U.S. versus Canada, and points to states in the Deep South, Appalachia, and parts of the West as having particularly high pain burden. The findings identify geographic areas with a high need for pain prevention and management.

General self-efficacy and social support in men and women with pain - irregular sex patterns of cross-sectional and longitudinal associations in a general population sample

BACKGROUND

The study of sex and gender patterns in psychosocial resources is a growing field of interest in pain research with importance for pain rehabilitation and prevention. The aims of this study were first, to estimate cross-sectional differences in psychosocial resources (general self-efficacy and social support) across men and women in a population with frequent musculoskeletal pain (pain in the back or neck/shoulder nearly every day or now and again during the week for the last 12 months) and to compare these differences with a population with no frequent pain. Second, to examine if psychosocial resources at baseline were associated with pain at follow-up among men and women in the frequent pain population.

METHODS

This study was based on survey data from the Swedish Health Assets Project, including The General Self-Efficacy Scale and social support questions. Participants (n = 4010, 55% women) were divided into no frequent pain (n = 2855) and frequent pain (n = 1155). General self-efficacy and social support were analyzed (cross-sectional and longitudinal data) with linear and logistic regressions.

RESULTS

Men, with and without frequent pain, had higher general self-efficacy than the corresponding groups in women. Women, with and without frequent pain, had stronger emotional social support than the corresponding groups in men. Men with no frequent pain had weaker instrumental social support than women with no frequent pain (OR = 0.64 (95% CI 0.47-0.87)), men with frequent pain did not (OR = 1.32 (95% CI 0.86-2.01)). In the frequent pain population, the interaction between sex and strong (compared to weak) emotional social support was statistically significant (p = 0.040) for no frequent pain at follow-up, with women having OR = 1.81 and men OR = 0.62. Among women, strong emotional social support was associated with no frequent pain at follow-up. Among men, strong emotional social support was associated with frequent pain at follow-up.

CONCLUSION

Some of the associations between general self-efficacy, social support and musculosceletal pain showed unexpected sex patterns. Gendered expectations might have relevance for some of the results.

Sexual dimorphism of early transcriptional reprogramming in degenerating peripheral nerves

Sexual dimorphism is a powerful yet understudied factor that influences the timing and efficiency of gene regulation in axonal injury and repair processes in the peripheral nervous system. Here, we identified common and distinct biological processes in female and male degenerating (distal) nerve stumps based on a snapshot of transcriptional reprogramming 24 h after axotomy reflecting the onset of early phase Wallerian degeneration (WD). Females exhibited transcriptional downregulation of a larger number of genes than males. RhoGDI, ERBB, and ERK5 signaling pathways increased activity in both sexes. Males upregulated genes and canonical pathways that exhibited robust baseline expression in females in both axotomized and sham nerves, including signaling pathways controlled by neuregulin and nerve growth factors. Cholesterol biosynthesis, reelin signaling, and synaptogenesis signaling pathways were downregulated in females. Signaling by Rho Family GTPases, cAMP-mediated signaling, and sulfated glycosaminoglycan biosynthesis were downregulated in both sexes. Estrogens potentially influenced sex-dependent injury response due to distinct regulation of estrogen receptor expression. A crosstalk of cytokines and growth hormones could promote sexually dimorphic transcriptional responses. We highlighted prospective regulatory activities due to protein phosphorylation, extracellular proteolysis, sex chromosome-specific expression, major urinary proteins (MUPs), and genes involved in thyroid hormone metabolism. Combined with our earlier findings in the corresponding dorsal root ganglia (DRG) and regenerating (proximal) nerve stumps, sex-specific and universal early phase molecular triggers of WD enrich our knowledge of transcriptional regulation in peripheral nerve injury and repair.

A framework for sex, gender, and diversity analysis in research

Funding agencies have ample room to improve their policies.

Sexually dimorphic transcriptional programs of early-phase response in regenerating peripheral nerves

The convergence of transcriptional and epigenetic changes in the peripheral nervous system (PNS) reshapes the spatiotemporal gene expression landscape in response to nerve transection. The control of these molecular programs exhibits sexually dimorphic characteristics that remain not sufficiently characterized. In the present study, we recorded genome-wide and sex-dependent early-phase transcriptional changes in regenerating (proximal) sciatic nerve 24 h after axotomy. Male nerves exhibited more extensive transcriptional changes with male-dominant upregulation of cytoskeletal binding and structural protein genes. Regulation of mRNAs encoding ion and ionotropic neurotransmitter channels displayed prominent sexual dimorphism consistent with sex-specific mRNA axonal transport in an early-phase regenerative response. Protein kinases and axonal transport genes showed sexually dimorphic regulation. Genes encoding components of synaptic vesicles were at high baseline expression in females and showed post-injury induction selectively in males. Predictive bioinformatic analyses established patterns of sexually dimorphic regulation of neurotrophic and immune genes, including activation of glial cell line-derived neurotrophic factor Gfra1 receptor and immune checkpoint cyclin D1 (Ccnd1) potentially linked to X-chromosome encoded tissue inhibitor of matrix metallo proteinases 1 (Timp1). Regulatory networks involving Olig1, Pou3f3/Oct6, Myrf, and Myt1l transcription factors were linked to sex-dependent reprogramming in regenerating nerves. Differential expression patterns of non-coding RNAs motivate a model of sexually dimorphic nerve regenerative responses to injury determined by epigenetic factors. Combined with our findings in the corresponding dorsal root ganglia (DRG), unique early-phase sex-specific molecular triggers could enrich the mechanistic understanding of peripheral neuropathies.

Gender Differences in Medication Adverse Effects Experienced by People Living With Chronic Pain

Objectives

Understanding gender differences in chronic pain (CP) outcome research is essential to optimal treatment delivery. This study explored the associations between gender identity, gender roles, and the number of non-life-threatening pain medication adverse effects reported as severe by people living with CP.

Methods

The analyses were conducted using the COPE Cohort, a dataset generated through a web-based recruitment of adults with CP. Participants were asked how they identified themselves (women, men, unknown, unspecified) and gender roles were measured using the Bem Sex-Role Inventory (subgroups were formed applying the median split method). Pain medication adverse effects were assessed using a standardized checklist (none/mild/moderate/severe). A zero-inflated Poisson model was used to assess gender identity, gender roles and their interaction as potential predictors of the number of pain medication adverse effects.

Results

A total of 1,343 participants reported using pain medications. Adjusting for potential confounders, both gender identity (men vs. women: ß = −0.32, p = 0.0024) and gender roles (androgynous vs. undifferentiated: ß = 0.26, p = 0.0030) were associated with the number of pain medication adverse effects reported as severe, and they interacted with each other. The stratified analysis by gender roles showed that women reported a greater number of severe adverse effects than men among those classified as masculine and androgynous.

Discussion

Although we are unable to confirm whether the associations can be explained by differences in the experience or in the reporting of effects, gender identity and gender roles should both be explored when studying pain medication adverse effects.

The Multifaceted Role of Mating Type of the Fungus and Sex of the Host in Studies of Fungal Infections in Humans

This review discusses the inclusion of sex and gender variables in studies of fungal infections in humans at the pathogen, host, and antifungal trial levels. The mating type of some fungi, or perhaps more likely the absence of the other, appears to be associated with some infections. Sexual and parasexual reproduction of some fungi is an important mechanism for the development of antifungal drug resistance. Host sex or gender influences the incidence of some infections such as aspergillosis, cryptococcosis, paracoccidioidomycosis, dermatophytosis, and candidiasis due to differences in immune response, behavior, and awareness for early detection and treatment. Participant sex (and age) is relevant not only in clinical antifungal trials but also in preclinical studies. The dimensions of sex and gender are important determinants throughout the fungal infection process and in approaches to prevent or treat these infections, as well as in development of antifungal drugs. Failure to consider sex and gender may be detrimental to the holistic understanding of the processes involved in fungal infection.

Sex-Specific B Cell and Anti-Myelin Autoantibody Response After Peripheral Nerve Injury

Immunotherapy holds promise as a non-addictive treatment of refractory chronic pain states. Increasingly, sex is recognized to impact immune regulation of pain states, including mechanical allodynia (pain from non-painful stimulation) that follows peripheral nerve trauma. This study aims to assess the role of B cells in sex-specific responses to peripheral nerve trauma. Using a rat model of sciatic nerve chronic constriction injury (CCI), we analyzed sex differences in (i) the release of the immunodominant neural epitopes of myelin basic protein (MBP); (ii) the levels of serum immunoglobulin M (IgM)/immunoglobulin G (IgG) autoantibodies against the MBP epitopes; (iii) endoneurial B cell/CD20 levels; and (iv) mechanical sensitivity behavior after B cell/CD20 targeting with intravenous (IV) Rituximab (RTX) and control, IV immunoglobulin (IVIG), therapy. The persistent MBP epitope release in CCI nerves of both sexes was accompanied by the serum anti-MBP IgM autoantibody in female CCI rats alone. IV RTX therapy during CD20-reactive cell infiltration of nerves of both sexes reduced mechanical allodynia in females but not in males. IVIG and vehicle treatments had no effect in either sex. These findings provide strong evidence for sexual dimorphism in B-cell function after peripheral nervous system (PNS) trauma and autoimmune pathogenesis of neuropathic pain, potentially amenable to immunotherapeutic intervention, particularly in females. A myelin-targeted serum autoantibody may serve as a biomarker of such painful states. This insight into the biological basis of sex-specific response to neuraxial injury will help personalize regenerative and analgesic therapies.

Modeling the transition from acute to chronic postsurgical pain in youth: A narrative review of epidemiologic, perioperative and psychosocial factors

A growing number of studies have identified high rates of pediatric chronic postsurgical pain (CPSP) after major surgery. Pediatric CPSP is associated with pain-related distress and comorbid mental health outcomes, such as anxiety and depression. From a biopsychosocial perspective, youth factors, such as genetics, epigenetics, sex, presurgical pain, sleep, anxiety, and pain catastrophizing, as well as parent factors, such as cognitive appraisals of their child’s pain expression and pain catastrophizing, converge and lead to chronic pain disability. A comprehensive and testable psychosocial model of the transition from acute to chronic pediatric postsurgical pain has not been developed. This narrative review begins by evaluating the epidemiology and trajectories of pediatric CPSP and moves on to examine the more influential psychosocial models that have been proposed to understand the development of pediatric CPSP. Much of the literature to date has been conducted on adolescents undergoing spinal fusion. To conceptualize the transition from acute to chronic pain in youth, a combined diathesis-stress and interpersonal fear avoidance model is presented. Novel areas of future research include the potential influence that siblings and peers have on a youth’s development of CPSP as well as the influence of gender.

Communicating Endometriosis Pain in France and Australia: An Interview Study

Endometriosis is characterized by persistent, fluctuating pain associated with menstruation, a biological function which is socially invisible. The degree and quality of pain cannot easily be measured, observed, or documented. Difficulties in communicating pain pose particular challenges when seeking diagnosis and support from health professionals. In this paper we explore the experiences and characterization of pain by thirteen Australian and thirteen French women with endometriosis. Data were collected through semi-structured interviews using a life-history approach to illness symptoms, diagnosis and treatment. We explore the experiences of women with endometriosis in two phases: from onset of symptoms to seeking advice from a clinician, and from first consulting a clinician to receiving a diagnosis. On average, initial pain symptoms were identified 2.1 years before consulting a health practitioner, after which women reported pain symptoms 8.5 years prior to diagnosis; that is, the time between consulting a clinician and receiving a diagnosis was almost four times the period between experiencing symptoms and consulting a doctor. Pain was often “made real” to doctors by findings consistent with endometriosis on ultrasound and MRI, mostly used in France, or laparoscopy, the predominant diagnostic tool in Australia. No woman described her practitioner using standardized pain assessment tools. Thus, the validation of pain relies largely on disease visibility and the clinician-classified degree of severity rather than self-reported grades of pain or impact on activities of daily living. The invisible and enigmatic pain of this chronic women's disease remains difficult to communicate to doctors, and the recognition of severe pain is often key to timely diagnostic procedures. Clinicians need to be more proactive about severe pain related to menstruation, taking into consideration women's individual circumstances, and maintain a high index of suspicion of underlying endometriosis as a condition characterized primarily by pain.

Biopsychosocial Factors Predicting Pain Among Individuals Experiencing the Novel Coronavirus Disease (COVID-19)

BACKGROUND

Pain is one of the most common symptoms of novel coronavirus disease (COVID-19). Being both a physical and a psychological experience, pain is affected by many factors, including biological, psychological, and social rather than a single variable.

AIMS

To determine the effects of biological, psychological, and social factors on pain level among participants experiencing with the COVID-19.

DESIGN

A web-based, retrospective, and descriptive study SETTING: Social media sources such as Facebook, WhatsApp, Instagram, and E-mail PARTICIPANTS: One hundred forty-nine participants were included.

METHODS

Data were collected based on the biopsychosocial model. Pain level was evaluated using the visual analog scale (VAS). The data were analyzed using descriptive, correlational statistics, and structural equation modeling.

RESULTS

The mean age of participants was 32.87 (SD = 11.32) years. The VAS scores were associated with gender (Z = -2.103, p = .035), and chronic disease status (Z = 3.001, p = .003), and the Chalder Fatigue Scale total score (β = 0.718, p < .001) associated with biological factors. The Coronavirus Anxiety Scale scores among psychological factors showed a direct impact on the VAS scores (β = 0.583, p < .001). The Patterns of Activity Measure-Pain total score examined within social factors directly affected the VAS score. The VAS score did not correlate with age, smoking status, hospitalization status, respiratory support, marital status, education level, employment, and income status.

CONCLUSIONS

The pain level in COVID-19 participants was determined by biological, psychological, and social factors. Females and participants with chronic illness, anxiety, fatigue, and low physical activity were found to experience high levels of pain. Education and counseling programs for pain management should be comprehensively structured and include anxiety reduction programs, and fatigue management.

Innovations and advances in modelling and measuring pain in animals

Best practices in preclinical algesiometry (pain behaviour testing) have shifted over the past decade as a result of technological advancements, the continued dearth of translational progress and the emphasis that funding institutions and journals have placed on rigour and reproducibility. Here we describe the changing trends in research methods by analysing the methods reported in preclinical pain publications from the past 40 years, with a focus on the last 5 years. We also discuss how the status quo may be hampering translational success. This discussion is centred on four fundamental decisions that apply to every pain behaviour experiment: choice of subject (model organism), choice of assay (pain-inducing injury), laboratory environment and choice of outcome measures. Finally, we discuss how human tissues, which are increasingly accessible, can be used to validate the translatability of targets and mechanisms identified in animal pain models.

Culture and musculoskeletal pain: strategies, challenges, and future directions to develop culturally sensitive physical therapy care

BACKGROUND

Pain experience has a multidimensional nature. Assessment and treatment recommendations for pain conditions suggest clinicians use biopsychosocial approaches to treat pain and disability. The current pain research is overwhelmingly skewed towards the study of biological and psychological factors including interventions, whereas, cultural factors are often ignored.

OBJECTIVE

The aims of this Masterclass is threefold: (1) to discuss cultural influences on pain, (2) to provide strategies for delivering appropriate pain education and exercises in culturally diverse people with chronic pain, and (3) to present challenges and future directions to clinicians and researchers.

DISCUSSION

Cultural factors have a relevant influence on the way individuals experience and manage health and illness. Thus, people with different cultural experience perceive, respond, communicate and manage their pain in different ways. In this aspect, the contents of pain education should be presented using different culturally appropriate examples, metaphors, images, and delivery methods that may enhance the impact of the message. Efforts should be made to produce and spread culturally adapted evidence-based materials and resources. In addition, a culturally sensitive approach may help to introduce patients to graded activities, so that they can apply these strategies in culturally acceptable and meaningful ways. Future studies should investigate the effectiveness of culturally-adapted interventions in pain-related outcomes in different pain conditions in patients with different cultural backgrounds.

Sexual Dimorphism of Early Transcriptional Reprogramming in Dorsal Root Ganglia After Peripheral Nerve Injury

Peripheral nerve injury induces genome-wide transcriptional reprogramming of first-order neurons and auxiliary cells of dorsal root ganglia (DRG). Accumulating experimental evidence suggests that onset and mechanistic principles of post-nerve injury processes are sexually dimorphic. We examined largely understudied aspects of early transcriptional events in DRG within 24 h after sciatic nerve axotomy in mice of both sexes. Using high-depth RNA sequencing (>50 million reads/sample) to pinpoint sexually dimorphic changes related to regeneration, immune response, bioenergy, and sensory functions, we identified a higher number of transcriptional changes in male relative to female DRG. In males, the decline in ion channel transcripts was accompanied by the induction of innate immune cascades via TLR, chemokine, and Csf1-receptor axis and robust regenerative programs driven by Sox, Twist1/2, and Pax5/9 transcription factors. Females demonstrated nerve injury-specific transcriptional co-activation of the actinin 2 network. The predicted upstream regulators and interactive networks highlighted the role of novel epigenetic factors and genetic linkage to sex chromosomes as hallmarks of gene regulation post-axotomy. We implicated epigenetic X chromosome inactivation in the regulation of immune response activity uniquely in females. Sexually dimorphic regulation of MMP/ADAMTS metalloproteinases and their intrinsic X-linked regulator Timp1 contributes to extracellular matrix remodeling integrated with pro-regenerative and immune functions. Lexis1 non-coding RNA involved in LXR-mediated lipid metabolism was identified as a novel nerve injury marker. Together, our data identified unique early response triggers of sex-specific peripheral nerve injury regulation to gain mechanistic insights into the origin of female- and male-prevalent sensory neuropathies.

Influences of Gender on Intravenous Nalbuphine Actions After Major Abdominal Surgery: A Multicenter Study

INTRODUCTION

Nalbuphine, a synthetic kappa-opioid receptor (KOR) agonist and a partial µ-opioid receptor (MOR) antagonist, has been used for years as an effective analgesic. It has been shown to have a better safety profile than morphine. Considering the long history of use of this drug, it is interesting that only a limited amount of information exists on how gender differences influence nalbuphine responses. In this randomized double-blind comparative trial after major abdominal surgery, the analgesic effects of two doses of continuous intravenous infusion of nalbuphine were evaluated based on gender.

METHODS

Enrolled patients were divided into four groups (two females and two males with 32 patients in each group). Two of them (groups A1 and A2), one male and one female, received postoperative continuous intravenous infusions of nalbuphine at 2 mg/h via patient-controlled analgesia (PCA). Each patient had the potential of receiving a rescue bolus of 1 mg of nalbuphine with a lock out time of 15 min. The other two groups (groups B1 and B2) received half the infusion dose, 1 mg/h, and half the nalbuphine rescue dose with the PCA pump, 0.5 mg maximum every 15 min as needed. Patients' vital signs, numerical pain rating scores, rescue nalbuphine, and incidence of side effects were assessed immediately after the operation, and every 3 h during the first 12 h.

RESULTS

Nalbuphine 2 mg/h dosing led to significantly lower pain scores amongst females compared to males at 6, 9, and 12 h; while the 1 mg/h infusion pain scores were only lower at the 9-h time period. Females receiving the nalbuphine 2 mg dose at 6 h, and the 1 mg dose at 6, 9, and 12-h measurements needed significantly lower doses of rescue nalbuphine. Females on the 1 mg dose experienced significantly more nausea, vomiting, and sedation at the 6-, 9-, and 12-h measurement times. In the multivariate analysis, female gender was a negative predictor at all measurement times.

CONCLUSIONS

The current study supports the hypothesis that although nalbuphine was found to be an effective and well-tolerated analgesic after major abdominal surgery, females were statistically more responsive than males.

TRIAL REGISTRATION

The study was registered at the Pan African Clinical trials Registry PACTR201304000486309, and approved for the Ethical aspects.

The Measurement and Conceptualization of Coping Responses in Pediatric Chronic Pain Populations: A Scoping Review

Background: Pediatric chronic pain is a prevalent condition that requires significant coping to encourage optimal functioning; however, relevant research is vast, heterogeneous, and difficult to interpret. To date, no attempt has been made to map and summarize the measurement and conceptualization of coping responses in the context of pediatric chronic pain. Objectives: A scoping review was conducted to map and summarize the participant characteristics, methodologies, theoretical frameworks, and measures used to assess coping responses in youth with chronic pain. The extent to which authors used definitions and examples of coping responses (conceptual clarity) as well as consistently used measures (measurement consistency) and their corresponding conceptualizations (conceptual consistency) relative to how they were intended to be used were assessed. Methods: Searches were conducted through MEDLINE (PubMed) and PsycINFO. Following title/abstract screening, full-text extractions were performed on 125 English-language publications on coping in youth with chronic pain. Results: Of the 125 studies, only 12.8% used a theoretical framework to explain the coping responses assessed, and even fewer (7.2%) used theory to guide measure selection. Conceptual clarity was rated "low/very low" (i.e., no definitions and/or examples) for 47.2% of studies. The majority of studies were conducted in the United States (67%) and a preponderance of White and female participants was sampled. The research primarily used quantitative methods (85%) and cross-sectional designs (67%). Parent- or self-report questionnaires were the most common methods for assessing coping (86%). Of the 95 studies that utilized one of the 14 questionnaires with known psychometric properties, 33.7 and 55.8% had one or more discrepancies for conceptual and measurement consistency, respectively. Conclusions: This review highlights the lack of clear descriptions and theoretical frameworks of coping responses for pediatric chronic pain. Inconsistencies in the measurement and conceptualization of coping responses limit research and clinical advancements. As a field, we need to strive toward using well-developed theory to create fewer, more well-established standardized measures with clearly defined coping responses. Opportunities for qualitative and observational research in more diverse patient populations should be considered for theory construction and measure validation. Clinical Trial Registration: https://osf.io/xvn2a/?view_only=eff04e0c0b9649be89d403b10e9ff082.

Gender Biases in Estimation of Others' Pain

Caregiving and other interpersonal interactions often require accurate perception of others' pain from nonverbal cues, but perceivers may be subject to systematic biases based on gender, race, and other contextual factors. Such biases could contribute to systematic under-recognition and undertreatment of pain. In 2 experiments, we studied the impact of perceived patient sex on lay perceivers' pain estimates and treatment recommendations. In Experiment 1 (N = 50), perceivers viewed facial video clips of female and male patients in chronic shoulder pain and estimated patients' pain intensity. Multi-level linear modeling revealed that perceivers under-estimated female patients' pain compared with male patients, after controlling for patients' self-reported pain and pain facial expressiveness. Experiment 2 (N = 200) replicated these findings, and additionally found that 1) perceivers' pain-related gender stereotypes, specifically beliefs about typical women's vs. men's willingness to express pain, predicted pain estimation biases; and 2) perceivers judged female patients as relatively more likely to benefit from psychotherapy, whereas male patients were judged to benefit more from pain medicine. In both experiments, the gender bias effect size was on average 2.45 points on a 0-100 pain scale. Gender biases in pain estimation may be an obstacle to effective pain care, and experimental approaches to characterizing biases, such as the one we tested here, could inform the development of interventions to reduce such biases. Perspective: This study identifies a bias towards underestimation of pain in female patients, which is related to gender stereotypes. The findings suggest caregivers' or even clinicians' pain stereotypes are a potential target for intervention.

Cross-national trends of chronic back pain in adolescents: results from the HBSC study, 2001-2014

Chronic back pain is a common problem that negatively impacts the wellbeing of many adolescents. Prior research suggests that the prevalence of chronic back pain has increased over the last decades, but research on this issue is scarce, single country-based, and has yielded inconsistent results. This study aimed to examine trends in the prevalence of chronic back pain over time in adolescents aged 11, 13 and 15, using data from the Health Behavior in School-aged Children (HBSC) survey. We conducted a secondary analysis of data from 650,851 adolescents, retrieved from four waves (2001/02, 2005/06, 2009/10 and 2013/14) of HBSC data from 33 countries or regions. The prevalence of back pain was higher (1) in each successive survey over time (18.3% in 2001/02, 19.3% in 2005/06, 20.4% in2009/10 and 21.6% in 2013/14), (2) in girls (21.9%) compared to boys (17.8%), and (3) in older adolescents compared to younger ones (14.5% in 11-year-olds, 19.6% in 13-year-olds and 25.5% in 15-year-olds). The increase in prevalence from 2001/02 to 2013/14 was more marked in older girls compared to younger girls, and in older boys compared to younger boys, and it ranged between 1% for 11-year-old boys and 7% for 15-year-old girls. More resources should be allocated to the prevention and treatment of chronic back pain in adolescents, especially for older girls.

Mouse Anesthesia: The Art and Science

There is an art and science to performing mouse anesthesia, which is a significant component to animal research. Frequently, anesthesia is one vital step of many over the course of a research project spanning weeks, months, or beyond. It is critical to perform anesthesia according to the approved research protocol using appropriately handled and administered pharmaceutical-grade compounds whenever possible. Sufficient documentation of the anesthetic event and procedure should also be performed to meet the legal, ethical, and research reproducibility obligations. However, this regulatory and documentation process may lead to the use of a few possibly oversimplified anesthetic protocols used for mouse procedures and anesthesia. Although a frequently used anesthetic protocol may work perfectly for each mouse anesthetized, sometimes unexpected complications will arise, and quick adjustments to the anesthetic depth and support provided will be required. As an old saying goes, anesthesia is 99% boredom and 1% sheer terror. The purpose of this review article is to discuss the science of mouse anesthesia together with the art of applying these anesthetic techniques to provide readers with the knowledge needed for successful anesthetic procedures. The authors include experiences in mouse inhalant and injectable anesthesia, peri-anesthetic monitoring, specific procedures, and treating common complications. This article utilizes key points for easy access of important messages and authors’ recommendation based on the authors’ clinical experiences.

Attentional Biases Towards Body Expressions of Pain in Men and Women

This study investigated whether there are gender differences in attention to bodily expressions of pain and core emotions. Three experiments are reported using the attentional dot probe task. Images of men and women displaying bodily expressions, including pain, were presented. The task was used to determine whether participants' attention was drawn towards or away from target expressions. Inconsistent evidence was found for an attentional bias towards body expressions, including pain. While biases were affected by gender, patterns varied across the Experiments. Experiment 1, which had a presentation duration of 500 ms, found a relative bias towards the location of male body expressions compared to female expressions. Experiments 2 and 3 varied stimulus exposure times by including both shorter and longer duration conditions (e.g., 100 vs. 500 vs. 1250 ms). In these experiments, a bias towards pain was confirmed. Gender differences were also found, especially in the longer presentation conditions. Expressive body postures captured the attention of women for longer compared to men. These results are discussed in light of their implications for why there are gender differences in attention to pain, and what impact this has on pain behaviour. PERSPECTIVE: We show that men and women might differ in how they direct their attention towards bodily expressions, including pain. These results have relevance to understanding how carers might attend to the pain of others, as well as highlighting the wider role that social-contextual factors have in pain.

Female Gender Is Associated with a Higher Prevalence of Chronic Neck Pain, Chronic Low Back Pain, and Migraine: Results of the Spanish National Health Survey, 2017

OBJECTIVES

To assess the prevalence of chronic neck pain (CNP), chronic low back pain (CLBP), and migraine headache (MH) in the Spanish population and to identify sociodemographic and health-related variables associated with CNP, CLBP, and MH.

DESIGN

Observational study.

SETTING

Spain.

SUBJECTS

A total of 22,511 persons 18 years of age or older (10,304 males and 12,207 females) who participated in the 2017 Spanish National Health Survey.

METHODS

Stratified three-stage sampling was applied. CNP, CLBP, and MH were the dependent variables. The analysis was conducted separately by gender. Sociodemographic features, self-perceived health status, lifestyle habits, comorbidities, and pain features were analyzed by using logistic regression models.

RESULTS

Females reported a higher prevalence of CNP, CLBP, and MH (P < 0.001) than males. For both sexes, anxiety and/or depression and poor self-rated health were associated with a significantly increased prevalence of CNP, CLBP, and MH. For CNP and CLBP, the identified associated factors were older age and limitations to usual activity. For CNP and MH, the most common associated factor was comorbid respiratory disease.

CONCLUSIONS

Our study identified several factors associated with CNP, CLBP, and MH in Spanish female and male adults, with potential implications for health care providers.

A qualitative study of the experience and impact of neuropathic pain in people living with HIV

Painful distal symmetrical polyneuropathy is common in HIV and is associated with reduced quality of life. Research has not explored the experience of neuropathic pain in people with HIV from a person-centred perspective. Therefore, a qualitative interview study was conducted to more deeply understand the experience and impact of neuropathic pain in this population. Semistructured interviews were conducted with 26 people with HIV and peripheral neuropathic pain symptoms. Interviews explored the impact of pain and participants' pain management strategies. Interviews were transcribed verbatim and analysed using thematic analysis. Four themes and 11 subthemes were identified. Theme 1 reflects the complex characterisation of neuropathic pain, including the perceived unusual nature of this pain and diagnostic uncertainty. Theme 2 centred on the interconnected impacts of pain on mood and functioning and includes how pain disrupts relationships and threatens social inclusion. Theme 3 reflects the struggle for pain relief, including participants' attempts to "exhaust all options" and limited success in finding lasting relief. The final theme describes how pain management is complicated by living with HIV; this theme includes the influence of HIV stigma on pain communication and pain as an unwanted reminder of HIV. These data support the relevance of investigating and targeting psychosocial factors to manage neuropathic pain in HIV.

Pain in Women: A Perspective Review on a Relevant Clinical Issue that Deserves Prioritization

Introduction

Gender equity and gender medicine are opportunities not to be missed, and this Expert Group Opinion Paper on pain in women aims to review the treatment of pain conditions mainly affecting women, as well as the fundamental aspects of the different clinical response to drug treatment between the genders, and what can be done for gender-specific rehabilitation.

Methods

Perspective review.

Results

Genotypic and phenotypic differences in pain between the sexes are conditioned by anatomical, physiological, neural, hormonal, psychological, social, and cultural factors, such as the response to pharmacological treatment to control pain. The examination of these factors shows that women are affected by pain diseases more frequently and severely than men and that they report pain more frequently and with a lower pain threshold than men. Some forms of pain are inherently related to gender differences, such as pain related to the genitourinary system. However, other forms of chronic pain are seen more frequently in women than men, such as migraine, rheumatological, and musculoskeletal pain, in particular fibromyalgia.

Discussion

Research is needed into the pathophysiological basis for gender differences in the generation of acute pain and maintenance of chronic pain, including the factors that put women at higher risk for developing chronic pain. In addition, different specialties need to collaborate to develop gender-related diagnostic and therapeutic guidelines, and healthcare professionals need to upskill themselves in the appropriate management of pain using existing diagnostic tools and therapeutic options.

Confirmatory factor analysis of the International Pain Outcome questionnaire in surgery

Supplemental Digital Content is Available in the Text.

The reliability and validity of International Pain Outcome questionnaire Spanish adaptation is confirmed in a large heterogeneous sample. Factor scores can be used as a global outcome analysis tool.

Background:

Choosing perioperative suitable treatments requires reliable and valid outcome measurements. The International Pain Outcome (IPO) questionnaire has been widely used for quality improvement and research purposes within the PAIN-OUT network that has collected more than 550,000 data sets of postoperative patients in 200 hospitals worldwide. Our aim is to confirm psychometric properties of the Spanish version of the IPO questionnaire and its invariance by pain predictors.

Method:

Sample included 4014 participants within a large age range, who underwent different surgical procedures. Confirmatory factor analysis (CFA) assessed internal structure, considering invariance by sex, age, procedure, smoking, obesity, affective disorder, and chronic pain. Incremental predictive validity of factor scores on question would have liked more pain treatment and opioid requirement was also estimated with logistic binary regression.

Results:

Confirmatory factor analysis verified original structure in 3 factors measuring pain intensity and interference (F1), adverse effects (F2), and perceptions of care (F3), with good internal consistency. Multigroup CFA analysis confirmed invariance by assessed pain predictors. Good incremental predictive capacity to identify would have liked more pain treatment was achieved.

Conclusion:

Our study confirms the factor structure, supports reliability, and adds some evidence of convergent validity of the Spanish adaptation of the IPO questionnaire. The sum of scores in its main factors serves a global outcome analysis tool. Low scores in F1 and F2 with high scores in F3 would indicate optimal quality of care.

Sexual dimorphism in the contribution of neuroendocrine stress axes to oxaliplatin-induced painful peripheral neuropathy

ABSTRACT

Although clinical studies support the suggestion that stress is a risk factor for painful chemotherapy-induced peripheral neuropathy (CIPN), there is little scientific validation to support this link. Here, we evaluated the impact of stress on CIPN induced by oxaliplatin, and its underlying mechanisms, in male and female rats. A single dose of oxaliplatin produced mechanical hyperalgesia of similar magnitude in both sexes, still present at similar magnitude in both sexes, on day 28. Adrenalectomy mitigated oxaliplatin-induced hyperalgesia, in both sexes. To confirm the role of neuroendocrine stress axes in CIPN, intrathecal administration of antisense oligodeoxynucleotide targeting β₂-adrenergic receptor mRNA both prevented and reversed oxaliplatin-induced hyperalgesia, only in males. By contrast, glucocorticoid receptor antisense oligodeoxynucleotide prevented and reversed oxaliplatin-induced hyperalgesia in both sexes. Unpredictable sound stress enhanced CIPN, in both sexes. The administration of stress hormones, epinephrine, corticosterone, and their combination, at stress levels, mimicked the effects of sound stress on CIPN, in males. In females, only corticosterone mimicked the effect of sound stress. Also, a risk factor for CIPN, early-life stress, was evaluated by producing both stress-sensitive (produced by neonatal limited bedding) and stress-resilient (produced by neonatal handling) phenotypes in adults. Although neonatal limited bedding significantly enhanced CIPN only in female adults, neonatal handling significantly attenuated CIPN, in both sexes. Our study demonstrates a sexually dimorphic role of the 2 major neuroendocrine stress axes in oxaliplatin-induced neuropathic pain.

Allodynia by Splenocytes From Mice With Acid-Induced Fibromyalgia-Like Generalized Pain and Its Sexual Dimorphic Regulation by Brain Microglia

Fibromyalgia (FM), a disease of unknown etiology characterized by chronic generalized pain, is partly recapitulated in an animal model induced by repeated acid saline injections into the gastrocnemius muscle. Here, we attempted to investigate the sex difference in pain hypersensitivity (mechanical allodynia and hypersensitivity to electrical stimulation) in the repeated acid saline-induced FM-like generalized pain (AcGP) model. The first unilateral acid injection into gastrocnemius muscle at day 0/D0 and second injection at D5 (post day 0, P0) induced transient and long-lasting mechanical allodynia, respectively, on both sides of male and female mice. The pretreatment with gonadectomy did not affect the first injection-induced allodynia in both sexes, but gradually reversed the second injection-induced allodynia in male but not female mice. Moreover, the AcGP in male mice was abolished by intracerebroventricular minocycline treatments during D4–P4 or P5–P11, but not by early treatments during D0–D5 in male but not female mice, suggesting that brain microglia are required for AcGP in late-onset and sex-dependent manners. We also found that the intravenous treatments of splenocytes derived from male but not female mice treated with AcGP caused allodynia in naive mice. In addition, the purified CD4⁺ T cells derived from splenocytes of acid-treated male mice retained the ability to cause allodynia in naive mice. These findings suggest that FM-like AcGP has multiple sexual dimorphic mechanisms.