Race and Sex Differences in Primary Appraisals, Catastrophizing, and Experimental Pain Outcomes

Disparities in Clinical and Experimental Pain Between Non-Hispanic White and Asian American Individuals With Knee Osteoarthritis and the Role of Pain Catastrophizing: Pilot Study in Florida

BACKGROUND

Although a few studies have delineated the disparities in knee osteoarthritis (KOA) pain between non-Hispanic White and Asian American individuals, a significant research gap persists in elucidating the mechanisms underlying these differences.

OBJECTIVE

This pilot study aims to examine psychological factors, specifically pain catastrophizing and negative affect, as potential explanatory mechanisms for these dissimilarities.

METHODS

A cross-sectional design was used. Forty community-dwelling participants aged 50-70 years with self-reported KOA pain, including 20 non-Hispanic White and 20 Asian American individuals, were recruited in North Central Florida. Clinical KOA pain intensity was assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and the 4 subscales of the Short-Form McGill Pain Questionnaire-2. Quantitative sensory testing was conducted to measure experimental sensitivity to heat- and mechanically induced pain, including heat pain, pressure pain threshold, and punctate mechanical pain, as well as inhibitory pain processes through conditioned pain modulation. Pain catastrophizing was evaluated using the Coping Strategies Questionnaire-Revised Pain Catastrophizing subscale, while negative affect was assessed using the Positive and Negative Affect Schedule. Bayesian mediation analyses were used to examine both direct and indirect effects (mediation) between variables.

RESULTS

Asian American individuals exhibited higher pain catastrophizing scores than non-Hispanic White individuals. Pain catastrophizing, at high levels, contributed to WOMAC and Short-Form McGill Pain Questionnaire-2, which measured clinical pain. Race had no direct effects on these pain scores but exerted significant indirect effects via pain catastrophizing (WOMAC pain: 0.96, 95% CI 0.03-2.16; continuous pain: 0.84, 95% CI 0.18-1.70; intermittent pain: 0.78, 95% CI 0.03-1.71; neuropathic pain: 0.43, 95% CI 0.03-0.95; and affective pain: 1.05, 95% CI 0.24-1.99); thus, pain catastrophizing likely fully mediated the relationship between race and these pain measures. While Asian American individuals reported greater experimental pain sensitivity (heat pain, pressure pain threshold, and punctate mechanical pain) than non-Hispanic White individuals, these racial effects were not mediated by pain catastrophizing. Asian American individuals reported higher negative affect scores compared with non-Hispanic White individuals; however, negative affect did not mediate the relationship between race and any pain measures.

CONCLUSIONS

 The results demonstrate the contribution of pain catastrophizing to clinical pain in Asian American individuals with KOA and identify it as a potential mechanism underlying group differences in KOA pain between non-Hispanic White and Asian American individuals. However, caution is warranted due to the exploratory nature of this study and the treatment of Asian American individuals as a monolithic sample. Hence, future replication with larger and more diverse samples is necessary. Additionally, the lack of mediation effects of pain catastrophizing in the relationship between race and experimental pain suggests the need to explore other factors, such as biological, genetic, social, and environmental influences. Moreover, further research is essential to clarify the role of negative affect.

Frequency of physical activity during leisure time and variables related to pain and pain medication use in Spanish adults: A cross-sectional study

BACKGROUND

Physical inactivity has been identified as a risk factor for pain.

OBJECTIVE

The main objective was to analyze the relationships between leisure time physical activity frequency (PAF) and pain prevalence, pain level, pain impairment, daily life pain impairment, and analgesic use in Spanish adults. In addition, risk factors such as sex, body mass index, marital status and social class were assessed for these pain variables in addition to PAF.

METHOD

Cross-sectional study based on data from the 2014 and 2020 European Health Surveys in Spain residents. The Chi-square test was used to analyze the relationship of dependence between the variables of interest. A correlation study calculating Spearman's rho and a multiple logistic regression were performed to assess risk factors for pain variables.

RESULTS

20,113 and 19,196 subjects with a median age of 49 and 52 years old in 2014 and 2020 European Health Surveys, respectively, were analyzed. Dependence relationships were found between PAF and pain variables (p<0.001). The prevalence of: pain, high levels of pain, pain impairment, high level of pain impairment and use analgesic were higher in the inactive population than in the rest of the PAF levels (36.7-53%) vs (18.6-44.3%), p<0.05. Weak correlations were found between PAF and pain variables (-0.177 ≤ Rho ≤ -0.107) (p<0.001). Logistics regression show that being active or very active reduces the odds of pain, the intensity of pain and being affected in daily activities due to pain by 0.524 to 0.776 times. Likewise, being active or very active reduces the odds of taking pain medication by 0.661 to 0.755 times. Also age, low social class, being a woman, and being obese increase of odds of pain, pain affectation and use of analgesics in both surveys by 1.008 to 2.202 times.

CONCLUSIONS

Physical inactivity was related to a higher prevalence of: pain, higher levels of pain, higher pain involvement and higher analgesic use. In addition, lower social class, being female, older age, and obesity were factors for higher odds of pain, pain involvement, and analgesic use in both surveys.

Altered Movement Coordination during Functional Reach Tasks in Patients with Chronic Low Back Pain and Its Relationship to Numerical Pain Rating Scores

Identifying the effects of pain catastrophizing on movement patterns in people with chronic low back pain (CLBP) has important clinical implications for treatment approaches. Prior research has shown people with CLBP have decreased lumbar-hip ratios during trunk flexion movements, indicating a decrease in the contribution of lumbar flexion relative to hip flexion during trunk flexion. In this study, we aim to explore the relationship between pain catastrophizing and movement patterns during trunk flexion in a CLBP population. Participants with CLBP (N = 98, male = 59, age = 39.1 ± 13.0) completed a virtual reality standardized reaching task that necessitated a progressively larger amount of trunk flexion. Specifically, participants reached for four virtual targets to elicit 15°, 30°, 45°, and 60° trunk flexion in the mid-sagittal plane. Lumbar flexion was derived from the motion data. Self-report measures of numerical pain ratings, kinesiophobia, and pain catastrophizing were obtained. Pain catastrophizing leads to decreased lumbar flexion angles during forward reaching. This effect is greater in females than males.

Bystander Acknowledgment Mitigates the Psychological and Physiological Pain of Racial Discrimination for Black Young Adults: A Randomized Controlled Trial

Racism increases pain sensitization and contributes to racialized pain inequities; however, research has not tested interventions targeting racism to reduce pain. In this study, we examined whether White bystanders can act to mitigate racism's pain-sensitizing effects. To simulate racial exclusion in the laboratory, Black young adults (age 18-30; N = 92) were randomly assigned to be included or excluded by White players in a ball-tossing game (Cyberball). For half of the excluded participants, White bystanders acknowledged and apologized for the racial exclusion. Participants completed a cold pressor task to assess pain threshold, tolerance, and unpleasantness, and completed a survey assessing psychological needs (ie, belongingness, self-esteem, meaningful existence, and self-control). Participants who experienced racial exclusion reported significantly more threatened psychological needs and increased laboratory pain sensitization (ie, lower pain threshold and tolerance) than those who were included. However, when a White bystander acknowledged the racism, excluded participants reported higher levels of self-control, self-esteem, and decreased pain sensitization (pain threshold and tolerance) relative to excluded participants whose experience was not acknowledged. Our findings support that racism increased Black people's pain sensitivity and provide initial evidence for White bystander acknowledgment as a health intervention. PERSPECTIVE: Continual exposure to racism likely contributes to inequities in pain sensitization. We demonstrate that acute exposure to mild racism increases acute pain sensitization. Results suggest that a bystander acknowledging witnessed racism can buffer the acute sensitizing effects of racism on pain, pointing to the potential of interpersonal interventions targeting racism. TRIAL REGISTRATION: Clinicaltrials.gov NCT06113926.

Sex differences in pain catastrophizing and its relation to the transition from acute pain to chronic pain

BACKGROUND AND IMPORTANCE

Differences exist between sexes in pain and pain-related outcomes, such as development of chronic pain. Previous studies suggested a higher risk for pain chronification in female patients. Furthermore, pain catastrophizing is an important risk factor for chronification of pain. However, it is unclear whether sex differences in catastrophic thinking could explain the sex differences in pain chronification.

OBJECTIVES

The aim of this study was to examine sex differences in pain catastrophizing. Additionally, we investigated pain catastrophizing as a potential mediator of sex differences in the transition of acute to chronic pain.

DESIGN, SETTINGS AND PARTICIPANTS

Adults visiting one of the 15 participating emergency departments in the Netherlands with acute pain-related complaints. Subjects had to meet inclusion criteria and complete questionnaires about their health and pain.

OUTCOMES MEASURE AND ANALYSIS

The outcomes in this prospective cohort study were pain catastrophizing (short form pain catastrophizing) and pain chronification at 90 days (Numeric Rating Scale ≥ 1). Data was analysed using univariate and multivariable logistic regression models. Finally, stratified regression analyses were conducted to assess whether differences in pain catastrophizing accounted for observed differences in pain chronification between sexes.

MAIN RESULTS

In total 1,906 patients were included. Females catastrophized pain significantly more than males (p < 0.001). Multiple regression analyses suggested that pain catastrophizing is associated with pain chronification in both sexes.

CONCLUSIONS

This study reported differences between sexes in catastrophic cognitions in the development of chronic pain. This is possibly of clinical importance to identify high-risk patients and ensure an early intervention to prevent the transition from acute to chronic pain.

The Relationship Between the Ability to Infer Another's Pain and the Expectations Regarding the Appearance of Pain Facial Expressions: Investigation of the Role of Visual Perception

Although pain is a commonly experienced and observed affective state, it is frequently misinterpreted, which leads to inadequate caregiving. Studies show the ability at estimating pain in others (estimation bias) and detecting its subtle variations (sensitivity) could emerge from independent mechanisms. While estimation bias is modulated by variables such as empathy level, pain catastrophizing tendency, and overexposure to pain, sensitivity remains unimpacted. The present study verifies if these 2 types of inaccuracies are partly explained by perceptual factors. Using reverse correlation, we measured their association with participants' mental representation of pain, or more simply put, with their expectations of what the face of a person in pain should look like. Experiment 1 shows that both parameters are associated with variations in expectations of this expression. More specifically, the estimation bias is linked with expectations characterized by salient changes in the middle face region, whereas sensitivity is associated with salient changes in the eyebrow region. Experiment 2 reveals that bias and sensitivity yield differences in emotional representations. Expectations of individuals with a lower underestimation tendency are qualitatively rated as expressing more pain and sadness, and those of individuals with a higher level of sensitivity as expressing more pain, anger, and disgust. Together, these results provide evidence for a perceptual contribution in pain inferencing that is independent of other psychosocial variables and its link to observers' expectations. PERSPECTIVE: This article reinforces the contribution of perceptual mechanisms in pain assessment. Moreover, strategies aimed to improve the reliability of individuals' expectations regarding the appearance of facial expressions of pain could potentially be developed, and contribute to decrease inaccuracies found in pain assessment and the confusion between pain and other affective states.

Secondary analysis: heat and self-report pain sensitivity associate with biological sex and racialized sociocultural group but may not be mediated by anxiety or pain catastrophizing

Introduction

Previous studies have demonstrated associations between sex and racialized group on pain sensitivity and tolerance. We analyzed the association of sex and racialized group on heat pain sensitivity, sensibility to painful suprathreshold mechanical pain (STMP), and pain sensitivity questionnaire (PSQ). We hypothesized that anxiety and pain catastrophizing reported by racialized minority groups and women would mediate enhanced pain sensitivity. Our secondary aim was to evaluate validity of the PSQ in a diverse population.

Methods

Using quantitative sensory testing for painful heat, STMP (forces: 64, 128, 256, and 512 mN), and PSQ, we evaluated pain sensitivity in 134 healthy participants [34 (18 women) Asian, 25 (13 women) Black, and 75 (41 women) White]. We used general linear and linear mixed models to analyze outcomes. We assessed mediation of state and trait anxiety and pain catastrophizing on pain sensitivity.

Results

Racialized minority status was associated with greater heat pain sensitivity (F = 7.63; P = 0.00074) and PSQ scores (F = 15.45; P = 9.84 × 10-7) but not associated with STMP (F = 1.50; P = 0.23). Female sex was associated with greater heat pain sensitivity (F = 4.9; P = 0.029) and lower PSQ (F = 9.50; P = 0.0025) but not associated with STMP (F = 0.0018; P = 0.97). Neither anxiety nor pain catastrophizing mediated associations between sex or racialized group with heat pain threshold or PSQ. Differential experience of individual items (F = 19.87; P = 3.28 × 10-8) limited PSQ face validity in racialized minorities.

Conclusion

Consistent with previous research, sensitivity to painful heat was associated with racialized minority status and female sex. By contrast, there was no significant effect of racialized minority status or female sex on STMP. Some PSQ items are inapplicable to participants from racialized minority groups.

Pain catastrophizing levels differentiate between common diseases with pain: HIV, fibromyalgia, complex regional pain syndrome, and breast cancer survivors

OBJECTIVES

Pain catastrophizing is a core psychological factor determining pain experience. We addressed the question of whether patients with different pain syndromes group into different pain catastrophizing phenotypes.

METHODS

A total of 727 patients with chronic pain associated with four primary syndromes: Breast cancer (BC) survivors (n = 400), fibromyalgia (FM, n = 52), complex regional pain syndrome (CRPS, n = 155), and HIV (n = 120) were first studied for differences in levels of pain catastrophizing (Pain Catastrophizing Scale, PCS) and pain intensity by analysis of variance. Subsequently, individual scores of the PCS subscales "rumination", "magnification," and "helplessness" from the pooled cohorts were submitted to multivariate k-means clustering to explore subgroups.

RESULTS

Three clusters defined by the level of catastrophizing were identified. The "low catastrophizing" cluster (n = 377) included most of the BC patients (71.0%) and the "moderate catastrophizing" cluster (n = 256) most of the FM patients (61.5%). HIV (31.9%) and CRPS (44.7%) patients were over-represented in the "high catastrophizing" cluster (n = 94) with the highest catastrophizing tendencies in all dimensions. These patients reported more helplessness than the patients in the two other clusters.

CONCLUSIONS

The primary syndrome causing the pain has an impact on self-reported pain-related catastrophizing. Helplessness is a predominant feature in HIV and CRPS patients and therefore an important target in pain rehabilitation.

Cognitive-Affective-Behavioral Pathways Linking Adversity and Discrimination to Daily Pain in African-American Adults

The tendency to ruminate, magnify, and experience helplessness in the face of pain - known as pain catastrophizing - is a strong predictor of pain outcomes and is associated with adversity. The ability to maintain functioning despite adversity - referred to as resilience - also influences pain outcomes. Understanding the extent to which pain catastrophizing and resilience influence relations between adversity and daily pain in healthy African-American adults could improve pain risk assessment and mitigate racial disparities in the transition from acute to chronic pain. This study included 160 African-American adults (98 women). Outcome measures included daily pain intensity (sensory, affective) and pain impact on daily function (pain interference). Adversity measures included childhood trauma exposure, family adversity, chronic burden from recent stressors, and ongoing perceived stress. A measure of lifetime racial discrimination was also included. Composite scores were created to capture early-life adversity (childhood trauma, family adversity) versus recent-life adversity (perceived stress, chronic burden). Increased pain catastrophizing was correlated with increased adversity (early and recent), racial discrimination, pain intensity, and pain interference. Decreased pain resilience was correlated with increased recent-life adversity (not early-life adversity or racial discrimination) and correlated with increased pain intensity (not pain-related interference). Bootstrapped multiple mediation models revealed that relationships between all adversity/discrimination and pain outcomes were mediated by pain catastrophizing. Pain resilience, however, was not a significant mediator in these models. These findings highlight opportunities for early interventions to reduce cognitive-affective-behavioral risk factors for persisting daily pain among African-American adults with greater adversity exposure by targeting pain catastrophizing.

Race, Ethnicity, and Belief in a Just World: Implications for Chronic Pain Acceptance Among Individuals with Chronic Low Back Pain

Chronic pain acceptance is a psychological process consistently linked with improved functional outcomes. However, existing research on this construct has not considered the role of racial or ethnic background, despite growing evidence of racialized disparities in pain experience and treatment. This study aimed to examine racial differences in chronic pain acceptance, as measured by the chronic pain acceptance questionnaires (CPAQ), in a multicultural sample of individuals with chronic low back pain (N = 137-37.2% White, 31.4% Hispanic, and 31.4% Black/African American). We further sought to examine moderating effects of discrimination, pain-related perceived injustice (PI), and just world belief (JWB). Analyses consisted of cross-sectional one-way analyses of variance with Bonferroni-corrected post hoc comparisons, followed by regression models with interaction terms, main effects, and relevant covariates. Results indicated higher scores on the CPAQ for White individuals compared to Black or Hispanic individuals. Significant interactions were noted between race/ethnicity and JWB in predicting pain acceptance, after controlling for demographic and pain-related variables, such that the positive association between JWB and pain acceptance was significant for White participants only. Race/ethnicity did not show significant interactions with PI or prior racial discrimination. Findings highlight racial differences in levels of chronic pain acceptance, an adaptive pain coping response, and a stronger JWB appears to have a positive impact on pain acceptance for White individuals only. Results further confirm that members of disadvantaged racial groups may be more susceptible to poorer pain adjustment, which is the result of complex, multi-level factors. PERSPECTIVE: This study identifies racial differences in levels of pain acceptance, an adaptive psychological response to chronic pain, such that White individuals with chronic low back pain demonstrate higher levels of pain acceptance. The article further explores the impacts of intrapersonal and sociocultural variables on racial differences in pain acceptance.

Adverse Drug Reactions to Opioids: A Study in a National Pharmacovigilance Database

INTRODUCTION

Opioids are commonly used as analgesics; however, like any medicine, they can produce adverse drug reactions (ADRs), including nausea, constipation, dependence, and respiratory depression, that result in harmful and fatal events. Therefore, it is essential to monitor the safety of these drugs in clinical practice.

OBJECTIVE

This study aimed to characterize the safety profile of opioids by conducting a descriptive study based on a spontaneous reporting system (SRS) for ADRs in The Netherlands, focusing on abuse, misuse, medication errors, and differences between sexes.

METHODS

Reports submitted to the Netherlands Pharmacovigilance Centre Lareb from January 2003 to December 2021 with an opioid drug as the suspected/interacting medicine were analyzed. Reporting odds ratios (RORs) for drug-ADR combinations were calculated, analyzed, and corrected for sex and drug utilization (expenditure) for the Dutch population.

RESULTS

A total of 8769 reports were analyzed. Tramadol was the opioid with the most reports during the period (n = 2746), while oxycodone or tramadol had the highest number of reports per year in the study period. The most reported ADRs from opioid use were nausea, followed by dizziness and vomiting, independent of sex, and all of them were more often reported in women. Vomiting associated with tramadol (ROR females/males = 2.17) was significantly higher in women. Buprenorphine was responsible for most ADRs when corrected for expenditure, with high RORs observed with application site hypersensitivity, application site reaction, and application site rash. Fentanyl gave rise to most of the reports of ADRs concerning abuse, misuse, and medication errors.

CONCLUSION

Patients treated with opioids experienced ADRs, primarily nausea, dizziness, and vomiting. For those groups of drugs, no significant differences were found between the sexes, except for the vomiting associated with tramadol. In general, ADRs related to opioids presented higher RORs when uncorrected and corrected for sexes and expenditure than other drugs. There was more disproportionate reporting for ADRs concerning abuse, misuse, and medication errors for opioids than other drugs in the Dutch SRS.

Individual Dimensions of Pain Catastrophizing Do Not Mediate the Effect of Sociodemographic and Psychological Factors on Chronic Orofacial Pain Severity, Interference, and Jaw Limitation: A Structural Equation Modeling Approach

Pain catastrophization (PC), involving rumination, magnification, and helplessness, can be viewed as a coping strategy associated with chronic pain. PC is considered a driving force in mediating pain-related outcomes, but it is still unclear whether PC mediates the relationship between psychological and sociodemographic factors with chronic pain when considered in a single model. Using baseline data from a parent study, this study examined the effect of positive and negative psychological and sociodemographic factors on pain severity, interference, and jaw limitation mediated by the PC dimensions in a sample of 397 temporomandibular disorder (TMD) participants using structural equation modeling (SEM). SEM revealed that pain severity regressed on age, sex, education, and income; interference regressed on positive and negative psychological factors, education, and income; and jaw limitation regressed on age. The PC dimensions did not individually mediate these relationships. Although they jointly mediated the relationships between negative psychological factors and pain severity and between age and pain interference, the effect size was small, suggesting that PC is not a critical factor in mediating TMD pain outcomes. Reducing negative cognitions, not just PC, may be of greatest benefit to the most vulnerable TMD populations. PERSPECTIVE: This study examines sociodemographic and psychological factors that affect orofacial pain, finding that the pain catastrophizing dimensions do not mediate these relationships. Understanding which factors most strongly affect pain outcomes will help identify targets for intervention to produce the greatest benefit for the most vulnerable persons suffering from pain.

Exploring the Effect of Ethnicity on Chronic Orofacial Pain: A Comparative Study of Jewish and Arab Israeli Patients

The relationship between ethnicity and chronic pain has been studied worldwide. The population of Israel includes two main ethnic groups, 75% Jews and 21% Arabs. The purpose of this study was to compare orofacial chronic pain characteristics and treatment outcomes between Jewish and Arab Israeli citizens. Two hundred patients admitted to the Orofacial Pain Clinic at Hebrew University-Hadassah School of Dental Medicine between 2017 and 2022 were selected randomly for this historical cohort study. Our cohort included 159 (79.5%) Jews and 41 (20.5%) Arabs. Twenty-six pain-related variables were compared of which only two differed significantly between the two groups, awakening due to pain and mean muscle sensitivity; both indicators were higher in the Arab group (p < 0.05). No differences were found in any of the other variables such as diagnosis, pain severity, onset, and treatment outcome. This minimal difference may be explained by the equal accessibility to medical services for all citizens, and the diversity of our staff that includes Jew as well as Arab service providers. These factors minimize or even eliminate racial bias, language, and cultural barriers, and is reflected in the minor differences in orofacial pain characteristics found between the two main ethnic groups in Israel.

Differences Between East Asians and Westerners in the Mental Representations and Visual Information Extraction Involved in the Decoding of Pain Facial Expression Intensity

Effectively communicating pain is crucial for human beings. Facial expressions are one of the most specific forms of behavior associated with pain, but the way culture shapes expectations about the intensity with which pain is typically facially conveyed, and the visual strategies deployed to decode pain intensity in facial expressions, is poorly understood. The present study used a data-driven approach to compare two cultures, namely East Asians and Westerners, with respect to their mental representations of pain facial expressions (experiment 1, N=60; experiment 2, N=74) and their visual information utilization during the discrimination of facial expressions of pain of different intensities (experiment 3; N=60). Results reveal that compared to Westerners, East Asians expect more intense pain expressions (experiments 1 and 2), need more signal, and do not rely as much as Westerners on core facial features of pain expressions to discriminate between pain intensities (experiment 3). Together, those findings suggest that cultural norms regarding socially accepted pain behaviors shape the expectations about pain facial expressions and decoding visual strategies. Furthermore, they highlight the complexity of emotional facial expressions and the importance of studying pain communication in multicultural settings.

Supplementary Information

The online version contains supplementary material available at 10.1007/s42761-023-00186-1.

Early life factors associated with the experiences of pain in later life: evidence from a population based study in India

BACKGROUND

The influence of early life factors is becoming increasingly apparent as studies investigate how experiences, resources, and constraints in childhood affect health and well-being later in life. The present study contributes to this literature by examining the association between several early life factors and self-reported pain among older adults in India.

METHODS

Data come from the 2017-18 wave 1 of the Longitudinal Ageing Study of India (LASI). The sample size includes 28,050 older adults aged 60 and above (13,509 men and 14,541 women). Pain is a self-reported, dichotomous measure where participants responded to whether they were often troubled with pain and whether this experience interfered with their ability to carry out daily household chores. Early life factors, which are retrospective accounts of experiences, included the respondent's position in birth order, their health status, school absenteeism, being bedridden, family socioeconomic status (SES), and their parent's experience with chronic disease. Logistic regression analysis is employed to examine the unadjusted and adjusted average marginal effects (AME) of selected domains of early life factors associated with the probability of experiencing pain.

RESULTS

22.8% of men and 32.3% of women reported pain that interfered with daily activities. Pain was higher among men (AME: 0.01, confidence interval (CI): 0.01-0.03) and women (AME: 0.02, CI: 0.01-0.04) with third or fourth birth order compared to counterparts with first birth order. Both men (AME: -0.02, CI: -0.04-0.01) and women (AME: -0.07, CI: -0.09 - -0.04) having a fair childhood health status reported a lower probability of pain. The probability of pain was higher among both men (AME: 0.03, CI: 0.01-0.07) and women (AME: 0.07, CI: 0.03-0.13) who were bedridden due to sickness in their childhood. Similarly, the pain likelihood was higher among men who missed school for more than a month due to health problems (AME: 0.04, CI: -0.01-0.09). Men and women with poor financial condition in their childhood reported (AME: 0.04, CI: 0.01-0.07) a higher probability of experiencing pain relative to their peers who reported a more financially advantaged early life.

CONCLUSIONS

Findings of the present study add to the empirical literature on the association between early life factors and later life health and well-being. They also are pertinent to health care providers and practitioners working in pain management, as this knowledge better positions them to identify older adults most susceptible to pain. Moreover, findings of our study underscore that the interventions to ensure health and well-being in later life must start far earlier in the life course.

Automatic assessment of pain based on deep learning methods: A systematic review

BACKGROUND AND OBJECTIVE

The automatic assessment of pain is vital in designing optimal pain management interventions focused on reducing suffering and preventing the functional decline of patients. In recent years, there has been a surge in the adoption of deep learning algorithms by researchers attempting to encode the multidimensional nature of pain into meaningful features. This systematic review aims to discuss the models, the methods, and the types of data employed in establishing the foundation of a deep learning-based automatic pain assessment system.

METHODS

The systematic review was conducted by identifying original studies searching digital libraries, namely Scopus, IEEE Xplore, and ACM Digital Library. Inclusion and exclusion criteria were applied to retrieve and select those of interest, published until December 2021.

RESULTS

A total of one hundred and ten publications were identified and categorized by the number of information channels used (unimodal versus multimodal approaches) and whether the temporal dimension was also used.

CONCLUSIONS

This review demonstrates the importance of multimodal approaches for automatic pain estimation, especially in clinical settings, and also reveals that significant improvements are observed when the temporal exploitation of modalities is included. It provides suggestions regarding better-performing deep architectures and learning methods. Also, it provides suggestions for adopting robust evaluation protocols and interpretation methods to provide objective and comprehensible results. Furthermore, the review presents the limitations of the available pain databases for optimally supporting deep learning model development, validation, and application as decision-support tools in real-life scenarios.

Sex Differences in Pain and Its Treatment

Pain is a highly personal experience. Pain is often considered to be a purely neurologic phenomenon, but in actuality, it is a combination of both sensory and emotional experiences. This has sometimes been translated clinically toward a more mechanistic approach to the assessment and treatment of pain instead of one that does not discount pain mechanisms, but also is more inclusive of the need for humanism - considering the individual. In today's medical environment, more than ever before there is a significant amount of attention being paid to educating clinicians to better understand that several physiological, neurophysiological, and psychosocial factors can significantly impact responses to pain. The composition of these factors will be unique to that individual's life narrative, context, sex, and prior life experiences. Thus, the concept that a templated approach to pain assessment and pharmacotherapeutic treatment planning should not be expected to provide optimal patient satisfaction and treatment outcomes in the majority. The hypotheses that there may be sex-based differences in the pain experience in a variety of ways including pain sensitivity, tolerance to pain, threshold at which something becomes painful, and the effectiveness of endogenous pain modulation systems are not new and have been well represented in the literature. This chapter reviews important key findings in the scientific literature with respect to sex-based differences in pain and pain responses to experimentally induced painful stimuli, pain experienced in commonly occurring painful medical conditions, and variations in responses to pain treatments. Possible explanations to account for observed differences or similarities will also be discussed.

Lean Mass is Associated with, but Does Not Mediate Sex Differences in Pressure Pain Sensitivity in Healthy Adults

Background

Sex differences exist in pain sensitivity, however, the underlying mechanism(s) that explain these differences are not fully understood. Pain sensitivity has been shown to be influenced by body mass index, but limited data exist on the role of body composition on pain sensitivity. The purpose was to examine the influence of body composition on pain sensitivity in males and females.

Methods

This cross-sectional study design used pressure pain thresholds (PPT) of 87 participants (45 female) who were assessed in the vastus lateralis (leg PPT) and brachioradialis (arm PPT) using a pressure algometer. Fat and lean tissue were assessed via dual-energy X-ray absorptiometry (DXA). A two group by two limb, repeated measured ANOVA was used to assess differences between limbs and sex. Spearman correlations and hierarchical regression analyses were employed to determine the association between body composition and PPT.

Results

Males had higher PPTs then females (P<0.05) and had higher DXA assessed lean and lower levels fat mass (P<0.05). Total body and limb specific lean mass was associated with PPTs (r≥0.34; P<0.05). Hierarchical regression analysis revealed lean mass was a significant predictor of 8% of the variance in arm PPT (P<0.006) and 18% of the variance in leg PPT (P<0.001). However, lean mass was not found to statistically mediate the observed sex differences in PPT.

Conclusion

This finding suggests lean mass may play a previously unknown role in sex differences in pressure pain sensitivity. Future studies are needed to confirm this finding and a larger sample size is likely required to have sufficient power to perform the mediation analysis.

A Systematic Review of the Variation in Pain Catastrophizing Scale Reference Scores Based on Language Version and Country in Patients with Chronic Primary (Non-specific) Pain

INTRODUCTION

This systematic review aimed to investigate variations of reference scores for the Pain Catastrophizing Scale (PCS) between language versions and between countries in patients with chronic primary pain (CPP) or chronic primary pain, not otherwise specified (CPP-NOS).

METHODS

Electronic searches of the Ovid/Embase, Ovid/MEDLINE, and Ovid/PsycINFO databases were conducted to retrieve studies assessing PCS scores in adults with CPP or CPP-NOS proposed by the International Classification of Diseases, Eleventh Revision for any country where the translated PCS was available. The protocol for this systematic review was prospectively registered on the International Prospective Register of Systematic Reviews 2018 (registration number: CRD 42018086719).

RESULTS

A total of 3634 articles were screened after removal of duplicates. From these, 241 articles reporting on 32,282 patients with chronic pain were included in the review. The mean (± standard deviation) weighted PCS score across all articles was 25.04 ± 12.87. Of the 12 language versions and 21 countries included in the review, the weighted mean PCS score in Asian languages or Asian countries was significantly higher than that in English, European, and other languages or Western and other countries. The highest mean score of the weighted PCS based on language was in Japanese (mean 33.55), and the lowest was in Russian (mean 20.32). The highest mean score of the weighted PCS based on country was from Japan (mean 33.55), and the lowest was from Australia (mean 19.80).

CONCLUSION

The weighted PCS scores for people with CPP or CPP-NOS were significantly higher in Asian language versions/Asian countries than in English, European and other language versions or Western and other countries.

The distinct longitudinal impact of pain catastrophizing on pain interference among youth living with sickle cell disease and chronic pain

Youth living with chronic sickle cell disease (SCD) pain are at risk for psychosocial distress and high levels of pain catastrophizing that contribute to functional impairment. This study aimed to identify the unique long-term impact of pain catastrophizing on pain impairment among youth with SCD. Youth with chronic SCD pain (N = 63, 10-18 years old, 58.3% female, 95.1% Black or African American) were recruited within comprehensive SCD clinics and completed a battery of measures at baseline and 4-months follow-up. A linear hierarchical regression examined baseline demographic and clinical characteristics (child SCD genotype, age, and average pain intensity), psychosocial functioning (anxiety, depression), and pain catastrophizing as predictors of pain interference at 4-months follow-up. Pain catastrophizing was the only unique predictor of pain interference at 4-months follow-up. Among youth with chronic SCD pain, pain catastrophizing warrants greater consideration as an important predictor that influences pain management and overall functioning.

Pain catastrophizing and associated factors in preoperative total knee arthroplasty in Lanzhou, China: a cross-sectional study

Background

Pain catastrophizing in preoperative total knee arthroplasty (TKA) patients is associated with several poorly characterised factors in the literature. This study investigated the current state and associated factors of preoperative pain catastrophizing in patients undergoing TKA.

Methods

This descriptive cross-sectional study was conducted at the orthopedics ward of two tertiary hospitals in Lanzhou, China. Pain catastrophizing was measured using the Chinese versions of the Pain Catastrophizing Scale, Short Form-36 (physical function domain), Numerical Rating Scale, Oxford Knee Score, Hospital Anxiety and Depression Scale, and Life Orientation Test-Revised.

Results

The study included 360 participants. Preoperative TKA pain catastrophizing in all patients was high, with a mean score of 24.92 (SD: 12.38). The stepwise multiple linear regression analysis revealed anxiety (β = 0.548, P < 0.01), education level (β =  − 0.179, P < 0.01), physical function (β =  − 0.156, P < 0.01), and pain intensity during activity (β = 0.105, P = 0.015) as associated factors for pain catastrophizing, possibly explaining 51.2% of the total variation (F = 95.149, P < 0.01).

Conclusion

Anxiety was the most relevant factor for pain catastrophizing in patients with preoperative TKA. Lower education levels, poor physical function, and stronger pain intensity during the activity were also associated with pain catastrophizing.

Differences in the association between kappa opioid receptors and pain among Black and White adults with alcohol use disorders

BACKGROUND

The relationship between alcohol and pain is complex. Associations between pain and alcohol use disorder (AUD) vary by race, but the underlying biological basis is not understood. We examined the association of the kappa opioid receptor (KOR) with responses to the cold-pressor test (CPT), before and after treatment with the opioid antagonist naltrexone, among individuals with AUD who self-identified as Black or White.

METHODS

Thirty-seven individuals (12 Black, 24 White, and 1 Multiracial) with AUD participated in two CPTs, separated by 1 week during which they received naltrexone 100 mg daily. During each CPT, pain reporting threshold (PRT), average pain increase rate (APIR), relative pain recovery (RPR), and alcohol craving were recorded. KOR availability was measured using [¹¹ C]-LY2795050 positron emission tomography (PET) prior to treatment with naltrexone.

RESULTS

Black participants reported higher PRT and APIR than White participants during the CPT before, but not after, naltrexone treatment. Among Black participants, KOR availability was positively associated with PRT and APIR before, but not after naltrexone. Greater KOR availability was associated with faster RPR for White, but not Black, participants. The CPT induced more alcohol craving in Black than White participants, particularly in individuals with low KOR availability, an effect that was not attenuated by naltrexone.

CONCLUSIONS

KOR involvement and naltrexone effects on responses to the CPT were different between Black and White participants. These preliminary findings suggest that further exploration of the differences in the opioid system and pain among Black and White individuals with AUD and their relationship with naltrexone's effects is warranted.

The Association Between Adverse Life Events, Psychological Stress, and Pain-Promoting Affect and Cognitions in Native Americans: Results from the Oklahoma Study of Native American Pain Risk

Native Americans (NAs) experience higher rates of chronic pain. To examine the mechanisms for this pain inequity, we have previously shown that NAs report higher levels of pain-related anxiety and pain catastrophizing, which are in turn related to pronociceptive (pain-promoting) processes. But, it is currently unclear why NAs would report greater pain-related anxiety and catastrophizing. Given that NAs are also more likely to experience adverse life events (ALEs) and associated psychological distress, it was hypothesized that higher anxiety/catastrophizing in NAs would be partially explained by higher rates of ALEs and psychological distress. Structural equation modeling was used to analyze these pathways (NA ethnicity ➔ ALEs ➔ psychological distress ➔ pain anxiety/catastrophizing) in 305 healthy, pain-free adults (N = 155 NAs, N = 150 non-Hispanic Whites [NHWs]). Pain-related anxiety and situational pain catastrophizing were assessed in response to a variety of painful tasks. The Life Events Checklist was used to assess cumulative exposure to ALEs that directly happened to each participant. A latent psychological distress variable was modeled from self-reported perceived stress and psychological symptoms. Results found that NAs experienced more ALEs and greater psychological distress which was associated with higher rates of pain-related anxiety and pain catastrophizing. Notably, NAs did not report greater psychological distress when controlling for ALE exposure. This suggests that a higher risk of chronic pain in NAs may be due, in part, to psychological distress, pain-related anxiety, and pain catastrophizing that are promoted by exposure to ALEs. These results highlight several targets for intervention to decrease NA pain risk.

Associations between pain and physical activity among older adults

Objectives

Chronic pain is a significant societal problem and pain complaints are one of the main causes of work absenteeism and emergency room visits. Physical activity has been associated with reduced risk of suffering from musculoskeletal pain complaints, but the exact relationship in an older adult sample is not known.

Methods

Participants self-reported their physical activity level and whether they were often troubled by bone, joint, or muscle pain. Logistic regression analyses revealed the nature of the relationship between musculoskeletal pain and physical activity cross-sectionally and longitudinally over the course of 10 years. Data were taken from the English Longitudinal Study of Ageing, comprising of 5802 individuals residing in England aged 50 or older.

Results

Only high levels of physical activity were associated with a reduced risk of suffering from musculoskeletal pain compared to a sedentary lifestyle longitudinally. In addition, having low wealth, being female, and being overweight or obese were found to be risk factors for suffering from musculoskeletal pain.

Conclusions

The development of interventions aimed at alleviating and preventing musculoskeletal pain complaints might benefit from incorporating physical activity programs, weight loss, and aspects addressing wealth inequality to maximise their efficacy.

Comparing Self-Reported Pain During Intercourse and Pain During a Standardized Gynecological Exam at 12- and 24-Month Postpartum

BACKGROUND

There is limited information about the physical indicators and biopsychosocial predictors of self-reported pain during intercourse and pain during a gynecological examination at 12- and 24-month following childbirth.

AIM

This longitudinal study aimed to (i) Compare the findings from gynecological exams at 12- and 24-month postpartum for women with minimal vs clinically significant pain during intercourse; (ii) Assess the biomedical and psychosocial correlates of self-reported pain during intercourse and the vestibular pain index (VPI) from the cotton-swab test at 12- and 24-month postpartum; (iii) Establish the relationship between self-reported pain during intercourse and the cotton-swab test.

METHODS

Women (N = 97 at 12 months postpartum and N = 44 at 24-month postpartum) recruited from a local women's hospital completed online surveys in their first trimester of pregnancy and at 12- and 24-month postpartum to assess pain during intercourse and biopsychosocial variables. Those with clinically significant (pain ≥4/10 on a visual analogue scale) were matched with those reporting minimal pain (pain <3/10) and underwent a gynecological exam including a cotton-swab test. Descriptive analyses, multiple regressions, and bivariate correlations were conducted to address each of the study aims, respectively.

MAIN OUTCOME MEASURES

(i) Findings from the gynecological examination (ii) Numerical rating scale for the VPI; (iii) Visual analogue scale of pain during intercourse.

RESULTS

The majority of women in both pain groups had normal physical findings in the gynecological exam. Greater sexual distress and pain catastrophizing at 12- and 24-month postpartum were significantly associated with greater pain during intercourse at each time-point, respectively. Greater pain catastrophizing at 12 months postpartum was significantly associated with greater pain during the cotton-swab test at that time-point. Lower relationship satisfaction at 12 months postpartum was associated with greater VPI ratings at 24 months postpartum. Pain during intercourse and the VPI were moderately and positively correlated.

CLINICAL IMPLICATIONS

Addressing psychosocial variables may interrupt the maintenance of postpartum pain. Following an initial assessment, self-reported pain intensity may be a suitable proxy for repeated examinations.

STRENGTHS & LIMITATIONS

This study is the first to describe the physical findings and psychosocial predictors of pain during intercourse and the VPI at 12- and 24-month postpartum. The homogenous and small sample may limit generalizability.

CONCLUSION

There were no observable physical indicators of clinically significant postpartum pain during intercourse. Psychosocial variables were linked to women's greater postpartum pain during intercourse and VPI ratings.

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.

A Mediation Appraisal of Catastrophizing, Pain-Related Outcomes, and Race in Adults With Knee Osteoarthritis

The current cross-sectional study investigates whether pain catastrophizing mediates the relationship between ethnicity/race and pain, disability and physical function in individuals with knee osteoarthritis. Furthermore, this study examined mediation at 2-year follow-up. Participants included 187 community-dwelling adults with unilateral or bilateral knee pain who screened positive for knee osteoarthritis. Participants completed several self-reported pain-related measures and pain catastrophizing subscale at baseline and 2-year follow-up. Non-Hispanic Black (NHB) adults reported greater pain, disability, and poorer functional performance compared to their non-Hispanic White (NHW) counterparts (Ps < .05). NHB adults also reported greater catastrophizing compared to NHW adults. Mediation analyses revealed that catastrophizing mediated the relationship between ethnicity/race and pain outcome measures. Specifically, NHB individuals reported significantly greater pain and disability, and exhibited lower levels of physical function, compared to NHW individuals, and these differences were mediated by higher levels of catastrophizing among NHB persons. Catastrophizing was a significant predictor of pain and disability 2-years later in both ethnic/race groups. These results suggest that pain catastrophizing is an important variable to consider in efforts to reduce ethnic/race group disparities in chronic pain. The findings are discussed in light of structural/systemic factors that may contribute to greater self-reports of pain catastrophizing among NHB individuals. PERSPECTIVE: The current study examines whether pain catastrophizing mediates the relationship between ethnicity/race and OA-related pain, disability, and functional impairment at baseline and during a 2-year follow-up period in non-Hispanic Black and non-Hispanic White adults with knee pain. These results point to the need for interventions that target pain catastrophizing.

Effects of the ABCB1 c.3435C>T (rs1045642) Polymorphism on Heat Pain Perception in Opioid-Free Adults With Chronic Pain

BACKGROUND

The adenosine triphosphate-binding cassette, subfamily B, member 1 gene (ABCB1) encodes P-glycoprotein (P-gp) that influences the intracellular transport of solutes including endogenous opioid peptides. The primary objective of this study was to determine the effects of the ABCB1 polymorphism c.3435C>T (rs10454642) on heat pain (HP) perception in a group of opioid-free adults with chronic pain.

METHODS

Opioid-free adults with chronic pain consecutively admitted to a pain rehabilitation program comprised the study cohort (N = 134). Individuals were genotyped for the c.3435C>T (rs10454642) polymorphism. The polymorphism was analyzed with nonparametric tests using a dominant (cytosine-cytosine [CC] versus cytosine-thymine [CT] + thymine-thymine [TT]) and recessive (CC + CT versus TT) model of allele effects. Quantitative sensory testing was performed using the Computer Aided Sensory Evaluator IV system.

RESULTS

The distribution of genotypes was 22% (N = 29) for CC, 45% (N = 60) for CT, and 33% (N = 45) for TT (Hardy-Weinberg, P > .1). A significant association was observed between the recessive model and HP threshold. Standardized values of HP threshold were significantly greater in the TT group than the CC + CT group (median difference, -0.77; 95% confidence interval [CI], -1.49 to -0.23; P = .005), and the effect size estimate was small (Cliff delta = 0.30). In the dominant model, no significant difference in HP threshold was observed between the CC and CT + TT groups (median difference, -0.45; 95% CI, -1.15 to 0.00; P = .108).

CONCLUSIONS

These results posit that the efflux of endogenous opioid peptides is reduced in individuals with the TT genotype due to lower expression of P-gp, which, in turn, results in higher HP threshold. This study contributes to the emerging understanding of how the ABCB1 c.3435C>T polymorphism contributes to pain perception in opioid-free adults with chronic pain and provides the foundation for investigating the potential effects of this polymorphism on the clinical course of chronic pain.

Ethnic disparities in pain processing among healthy adults: μ-opioid receptor binding potential as a putative mechanism

Although ethnic differences in pain perception are well documented, the underlying mechanism for these outcomes has not been established. µ-opioid receptor (MOR) function might contribute to this disparity, given that MORs play a key role in pain sensitivity and modulation. However, no study has characterized ethnic differences in MOR physiology. This study sought to address this knowledge gap by examining differences in µ-selective agonist binding potential (BPND; [C]-Carfentanil) between 27 non-Hispanic black (NHB) and 27 demographically similar, non-Hispanic white participants. Participants completed questionnaires and two 90-minute high-resolution research tomograph positron emission tomography (PET) imaging sessions. During PET imaging, a capsaicin or control cream was applied to individuals' arms, and pain ratings were collected. Bonferroni-corrected PET volumes of interest analyses revealed significantly greater [C]-Carfentanil BPND among NHB participants in bilateral ventral striatum ([left]: F1,52 = 16.38, P < 0.001; [right]: F1,52 = 21.76, P < 0.001), bilateral dorsolateral prefrontal cortex ([left] F1,52 = 17.3, P < 0.001; [right]: F1,52 = 14.17, P < 0.001), bilateral subgenual anterior cingulate cortex ([left]: F1,52 = 10.4, P = 0.002; [right]: F1,52 = 12.91, P = 0.001), and right insula (F1,52 = 11.0, P = 0.002). However, there were no significant main effects of condition or ethnicity × condition interaction effects across models, likely attributable to individual variability in the direction of change within groups. BPND values were significantly correlated with pain ratings collected during the capsaicin condition (r range = 0.34-0.46, P range = 0.01-0.001). Results suggest that NHB individuals might have generally greater unoccupied MOR density than non-Hispanic white peers. Findings have implications for physiological differences underlying ethnicity-related pain disparities. If replicated, these results further emphasize the need for tailored treatments in historically underserved populations.

Race Differences in Resilience Among Older Adults with Chronic Low Back Pain

INTRODUCTION

Racial minorities are disproportionally affected by pain. Compared to non-Hispanic Whites (NHWs), non-Hispanic Blacks (NHBs) report higher pain intensity, greater pain-related disability, and higher levels of mood disturbance. While risk factors contribute to these disparities, little is known regarding how sources of resilience influence these differences, despite the growing body of research supporting the protective role of resilience in pain and disability among older adults with chronic pain. The current study examined the association between psychological resilience and pain, and the moderating role of race across these relationships in older adults with chronic low back pain (cLBP).

METHODS

This is a secondary analysis of the Adaptability and Resilience in Aging Adults (ARIAA). Participants completed measures of resilience (ie, gratitude, trait resilience, emotional support), as well as a performance-based measure assessing lower-extremity function and movement-evoked pain.

RESULTS

There were 45 participants that identified as non-Hispanic White (NHW) and 15 participants that identified as non-Hispanic Black (NHB). Race was a significant correlate of pain outcomes with NHBs reporting greater movement-evoked pain (r = 0.27) than NHWs. After controlling for relevant sociodemographic characteristics, measures of movement-evoked pain were similar across both racial groups, F (1, 48) = 0.31, p = 0.57. Moderation analyses revealed that higher levels of gratitude (b = -1.23, p = 0.02) and trait resilience (b = -10.99, p = 0.02) were protective against movement-evoked pain in NHWs. In contrast, higher levels of gratitude were associated with lower functional performance in NHBs (b = -0.13, p =0.02).

DISCUSSION

These findings highlight racial differences in the relationship between resilience and pain-related outcomes among older adults with cLBP. Future studies should examine the potential benefits of targeted interventions that improve resilience and ameliorate pain disparities among racial minorities.

Pain, Culture and Pedagogy: A Preliminary Investigation of Attitudes Towards "Reasonable" Pain Tolerance in the Grassroots Reproduction of a Culture of Risk

In recent years a considerable body of psychological research has explored the relationship between membership of socio-cultural groups and personal pain perception. Rather less systematic attention has, however, been accorded to how such group membership(s) might influence individual attitudes towards the pain of others. In this paper, immersion in the culture of competitive sport, widely regarded as being exaggeratedly tolerant of risky behaviours around pain, is taken as a case-in-point with students of Physical Education (PE) in tertiary education as the key focus. PE students are highly-immersed in competitive sporting culture both academically and (typically) practically, and also represent a key nexus of cross-generational transmission regarding the norms of sport itself. Their attitudes towards the pain that others should reasonably tolerate during a range of activities, sporting and otherwise, were evaluated through a direct comparison with those of peers much less immersed in competitive sporting culture. In total, N=301 (144 PE, 157 non-PE) undergraduate students in the UK responded to a vignette-based survey. Therein, all participants were required to rate the pain (on a standard 0-10 scale) at which a standardised "other" should desist engagement with a set of five defined sporting and non-sporting tasks, each with weak and strong task severities. Results indicated that PE students were significantly more likely to expect others to persevere through higher levels of pain than their non-PE peers, but only during the sport-related tasks - an effect further magnified when task severity was high. In other tasks, there was no significant difference between groups, or valence of the effect was actually reversed. It is argued that the findings underscore some extant knowledge about the relationship between acculturated attitudes to pain, while also having practical implications for understanding sport-based pedagogy, and its potentially problematic role in the ongoing reproduction of a "culture of risk."

Overview of Genetic Analysis of Human Opioid Receptors

The human μ-opioid receptor gene (OPRM1 ), due to its genetic and structural variation, has been a target of interest in several pharmacogenetic studies. The μ-opioid receptor (MOR ), encoded by OPRM1 , contributes to regulate the analgesic response to pain and also controls the rewarding effects of many drugs of abuse, including opioids, nicotine, and alcohol. Genetic polymorphisms of opioid receptors are candidates for the variability of clinical opioid effects. The non-synonymous polymorphism A118G of the OPRM1 has been repeatedly associated with the efficacy of treatments for pain and various types of dependence. Genetic analysis of human opioid receptors has evidenced the presence of numerous polymorphisms either in exonic or in intronic sequences as well as the presence of synonymous coding variants that may have important effects on transcription, mRNA stability, and splicing, thus affecting gene function despite not directly disrupting any specific residue. Genotyping of opioid receptors is still in its infancy and a relevant progress in this field can be achieved by using advanced gene sequencing techniques described in this review that allow researchers to obtain vast quantities of data on human genomes and transcriptomes in a brief period of time and with affordable costs.

A Preliminary Investigation of the Underlying Mechanism Associating Daily Sleep Continuity Disturbance and Prescription Opioid Use Among Individuals With Sickle Cell Disease

BACKGROUND

There are emerging data indicating that sleep disturbance may be linked with an increase in opioid use. The majority of sickle cell disease (SCD) patients experience sleep disturbances, which can elevate pain severity and pain catastrophizing, both of which are important predictors of opioid consumption.

PURPOSE

We conducted a preliminary investigation on the association between previous night sleep disturbance and short-acting opioid use, as well as the potential mediating roles of pain severity and pain catastrophizing. Because sex is associated with sleep disturbance, pain-related experiences, and opioid use, we also explored the potential moderating role of sex.

METHODS

Participants were 45 SCD patients who were prescribed opioids. For 3 months, sleep diaries were collected immediately upon participants' awakening. Daily pain severity, pain catastrophizing, and prescription opioid use measures were collected before bedtime.

RESULTS

Multilevel structural equation modeling revealed that wake time after sleep onset (WASO) during the previous night (Time 1) predicted greater short-acting opioid use during the next day (Time 2). Pain severity and pain catastrophizing measured during the next day (Time 2) also mediated the association between the two. Sex moderation analysis showed that the positive association between WASO and pain severity was largely driven by women.

CONCLUSION

These findings provide some preliminary evidence as to the mechanism linking sleep continuity disturbance and opioid requirement in SCD patients. Future studies should replicate and extend these findings with clearer temporal information and employing more refined measures of sleep continuity and prescription opioid use in a larger sample.

Pain relief for osteoarthritis through combined treatment (PROACT): Protocol for a randomized controlled trial of mindfulness meditation combined with transcranial direct current stimulation in non-Hispanic black and white adults with knee osteoarthritis

Knee osteoarthritis (OA) is a leading cause of late life pain and disability, and non-Hispanic black (NHB) adults experience greater OA-related pain and disability than non-Hispanic whites (NHWs). Recent evidence implicates psychosocial stress, cognitive-attentional processes, and altered central pain processing as contributors to greater OA-related pain and disability among NHBs. To address these ethnic/race disparities, this clinical trial will test whether a mindfulness intervention (Breathing and Attention Training, BAT) combined with transcranial direct current stimulation (tDCS) will enhance pain modulatory balance and pain-related brain function, reduce clinical pain, and attenuate ethnic differences therein, among NHBs and NHWs with knee OA. Participants will complete assessments of clinical pain, function, psychosocial measures, and quantitative sensory testing (QST), including mechanical temporal summation and conditioned pain modulation. Neuroimaging will be performed to examine pain-related brain structure and function. Then, participants will be randomized to one of four groups created by crossing two BAT conditions (Real vs. Sham) with two tDCS conditions (Real vs. Sham). Participants will then undergo five treatment sessions during which the assigned BAT and tDCS interventions will be delivered concurrently for 20 min over one week. After the fifth intervention session, participants will undergo assessments of clinical pain and function, QST and neuroimaging identical to the pretreatment measures, and monthly follow-up assessments of pain will be conducted for three months. This will be the first study to determine whether mindfulness and tDCS treatments will show additive or synergistic effects when combined, and whether treatment effects differ across ethnic/race groups.

Testing a positive-affect induction to reduce verbally induced nocebo hyperalgesia in an experimental pain paradigm

There is an ethical obligation to notify individuals about potential pain associated with diagnoses, treatments, and procedures; however, supplying this information risks inducing nocebo hyperalgesia. Currently, there are few empirically derived strategies for reducing nocebo hyperalgesia. Because nocebo effects are linked to negative affectivity, we tested the hypothesis that a positive-affect induction can disrupt nocebo hyperalgesia from verbal suggestion. Healthy volunteers (N = 147) were randomly assigned to conditions in a 2 (affect induction: positive vs neutral) by 2 (verbal suggestion: no suggestion vs suggestion of pain increase) between-subjects design. Participants were induced to experience positive or neutral affect by watching movie clips for 15 minutes. Next, participants had an inert cream applied to their nondominant hand, and suggestion was manipulated by telling only half the participants the cream could increase the pain of the upcoming cold pressor test. Subsequently, all participants underwent the cold pressor test (8 ± 0.04°C), wherein they submerged the nondominant hand and rated pain intensity on numerical rating scales every 20 seconds up to 2 minutes. In the neutral-affect conditions, there was evidence for the nocebo hyperalgesia effect: participants given the suggestion of pain displayed greater pain than participants not receiving this suggestion, P's < 0.05. Demonstrating a blockage effect, nocebo hyperalgesia did not occur in the positive-affect conditions, P's > 0.5. This is the first study to show that positive affect may disrupt nocebo hyperalgesia thereby pointing to a novel strategy for decreasing nocebo effects without compromising the communication of medical information to patients in clinical settings.

Meta-analysis of the psychometric properties of the Pain Catastrophizing Scale and associations with participant characteristics

The aims of this study were to review the psychometric properties of the widely used Pain Catastrophizing Scale (PCS) using meta-analytic methods and to investigate the relationship between PCS scores and participant characteristics. A systematic search from 1995 found 229 experimental, quasi-experimental, and correlational studies that report PCS scores. Multivariate regression explored variables related to pain catastrophizing and participant demographics. Across studies, good internal reliability (α = 0.92, 95% confidence interval 0.91-0.93) and test-retest reliability scores (Spearman ρ = 0.88, 95% confidence interval 0.83-0.93) were found for PCS total scores but not for subscales. Pain Catastrophizing Scale scores were unrelated to age or sex, but strongly related to participants' pain type, highest in those with generalized pain. Language of the PCS also affected PCS scores, with further research necessary to determine linguistic, cultural, or methodological (eg, sampling strategy) influences. Study type influenced PCS scores with nonrandomized controlled trials reporting higher PCS scores than other study types, but results were confounded with pain diagnosis, as controlled trials were more likely than quasi-experimental studies to recruit clinical samples. The meta-analytic results provide insights into demographic influences on pain catastrophizing scores and highlight areas for further research. The advantages of systematic review and meta-analytic methods to achieve greater understanding and precision of psychometric properties-in this case, of the PCS-are applicable to other widely used outcome tools.

The Concerns About Pain (CAP) Scale: A Patient-Reported Outcome Measure of Pain Catastrophizing

Pain catastrophizing has been recognized as an important and consistent psychosocial predictor of nearly every key pain-related outcome. The purpose of this study was to develop a new measure of pain catastrophizing using modern psychometric methodology. People with chronic pain (N = 795) responded to thirty items. Data were analyzed using item response theory, including assessment of differential item functioning and reliability. Sensitivity to change and validity were examined using data collected from patients undergoing spinal fusion surgery (n = 184) and participating in an ongoing longitudinal aging with a disability survey study (n = 1,388). The final 24-item bank had no items with significant local dependence, misfit, or differential item functioning. Results provided strong evidence of reliability and validity. Six- and 2-item short forms were developed for use when computer adaptive testing is not feasible or desirable. The item bank was named the University of Washington Concerns About Pain scale because the term "catastrophizing" was considered stigmatizing by people with chronic pain. Guidance for score interpretation was developed with extensive feedback from individuals with chronic pain. The Concerns About Pain item bank, short forms, and user manuals are free and publicly available to all users and can be accessed online at https://uwcorr.washington.edu/measures/. PERSPECTIVE: This article presents the development of the University of Washington Concerns About Pain scale, the first item response theory-based item bank of pain catastrophizing. The measure is intended for clinicians interested in improving outcomes of patients with chronic pain and for researchers who study impact of and treatment interventions aimed at reducing pain catastrophizing.

Sex-Specific Pharmacotherapy for Migraine: A Narrative Review

Migraine is a common neurological disorder characterized by recurrent headache episodes that accompany sensory-motor disturbances, such as higher sensitivity to touch and light, extremity heaviness or weakness, and speech or language disabilities. Worldwide, migraine is one of the top 10 causes of disability and hence poses a huge economic burden to society. On average, migraine occurs in 12% of population but its occurrence is sexually dimorphic, as it is two to three times more prevalent in women than in men. This female to male ratio of migraine prevalence is age- and sex hormone-dependent. Advancements in understanding migraine pathogenesis have also revealed an association with both genetics and epigenetics. The severity of migraine, in terms of its attack duration, headache intensity, frequency, and occurrence of migraine-associated symptoms, has generally been reported to be greater in women. Sex differences in migraine disability and comorbidities, such as psychiatric disorders, have also been noted in some population-based studies. However, research on sex-related differences in response to migraine treatments is relatively scarce. Although a general observation is that women consume more medication than men for migraine treatment, strategies for the use of abortive and preventive medications for migraine are generally similar in both sexes. This narrative review summarizes available findings on sexually distinct responses to abortive and prophylactic pharmacotherapy of migraine. Basic experimental data and clinical findings will be presented, and potential mechanisms underlying sex-based responses will be discussed to highlight the importance and value of sex-based treatment in migraine research and practice.

The Operant Plantar Thermal Assay: A Novel Device for Assessing Thermal Pain Tolerance in Mice

Pain is a multidimensional experience of sensory-discriminative, cognitive, and affective processes; however, current basic research methods rely heavily on response to threshold stimuli, bypassing the supraspinal processing that ultimately gives rise to the pain experience. We developed the operant plantar thermal assay (OPTA), which utilizes a novel, conflict-based operant task requiring evaluation and active decision-making to obtain reward under thermally aversive conditions to quantify thermal pain tolerance. In baseline measures, male and female mice exhibited similar temperature preferences, however in the OPTA, female mice exhibited greater temperature-dependent tolerance, as defined by choice time spent in an adverse thermal condition to obtain reward. Increasing reward salience (4% vs 10% sucrose solution) led to increased thermal tolerance for males but not females. To determine whether neuropathic and inflammatory pain models alter thermal tolerance, animals with chronic constriction injury (CCI) or complete Freund's adjuvant (CFA), respectively, were tested in the OPTA. Surprisingly, neuropathic animals exhibited increased thermal tolerance, as shown by greater time spent in the reward zone in an adverse thermal condition, compared with sham animals. There was no effect of inflammation on thermal tolerance. Administration of clonidine in the CCI model led to increased thermal tolerance in both injured and sham animals. In contrast, the non-steroidal anti-inflammatory meloxicam was anti-hyperalgesic in the CFA model, but reduced thermal pain tolerance. These data support the feasibility of using the OPTA to assess thermal pain tolerance to gain new insights into complex pain behaviors and to investigate novel aspects of analgesic efficacy.

The roles of race, sex and cognitions in response to experimental pain

BACKGROUND

This study reports a multivariate test of sex and race differences in experimental pain, and the degree to which these differences could be uniquely attributable to three levels of cognition: primary appraisals (threat, challenge), secondary appraisals (pain catastrophizing) and/or cognitive processes (mindful observing, non-reactivity). Both the predictive and mediator role of the cognitive variables was of interest.

METHODS

The study employed a cross-sectional experimental design, with the cold pressor task employed as the pain stimulus. The total sample included N = 355 healthy adults (67% female, 33% male; 70% Caucasian, 30% Asian).

RESULTS

Significant sex and race differences on pain tolerance were found, with females and racial minorities reporting less pain tolerance (ps < 0.001). Males reported significantly higher challenge appraisals and non-reactivity, and lower pain catastrophizing than females; Asians reported significantly higher threat appraisals and pain catastrophizing than Caucasians. In multivariate analyses, challenge appraisals and non-reactivity emerged as the strongest predictors of pain tolerance. Furthermore, challenge appraisals mediated the sex-pain tolerance association (p = .017).

CONCLUSIONS

This study showed that race and sex differences, at least in part, may be accounted for by differences in pain-related cognitions.

SIGNIFICANCE

The three levels of cognition investigated in this research represent changeable, important processes for potentially mitigating the impact of pain in vulnerable groups.

Alcohol and Pain: A Translational Review of Preclinical and Clinical Findings to Inform Future Treatment Strategies

Alcohol use disorder (AUD) and chronic pain are enduring and devastating conditions that share an intersecting epidemiology and neurobiology. Chronic alcohol use itself can produce a characteristic painful neuropathy, while the regular analgesic use of alcohol in the context of nociceptive sensitization and heightened affective pain sensitivity may promote negative reinforcement mechanisms that underlie AUD maintenance and progression. The goal of this review was to provide a broad translational framework that communicates research findings spanning preclinical and clinical studies, including a review of genetic, molecular, behavioral, and social mechanisms that facilitate interactions between persistent pain and alcohol use. We also consider recent evidence that will shape future investigations into novel treatment mechanisms for pain in individuals suffering from AUD.

Race-related differences in acute pain complaints among inner-city women: the role of socioeconomic status

Previous research has shown that African Americans (AA) report higher pain intensity and pain interference than other racial/ethnic groups as well as greater levels of other risk factors related to worse pain outcomes, including PTSD symptoms, pain catastrophizing, and sleep disturbance. Within a Conservation of Resources theory framework, we tested the hypothesis that socioeconomic status (SES) factors (i.e., income, education, employment, perception of income meeting basic needs) largely account for these racial/ethnic differences. Participants were 435 women [AA, 59.1%; Hispanic/Latina (HL), 25.3%; Non-Hispanic/White (NHW), 15.6%] who presented to an Emergency Department (ED) with an acute pain-related complaint. Data were extracted from psychosocial questionnaires completed at the participants' baseline interview. Structural equation modeling was used to examine whether racial/ethnic differences in pain intensity and pain interference were mediated by PTSD symptoms, pain catastrophizing, sleep quality, and sleep duration, and whether these mediation pathways were, in turn, accounted for by SES factors. Results indicated that SES factors accounted for the mediation relationships linking AA race to pain intensity via PTSD symptoms and the mediation relationships linking AA race to pain interference via PTSD symptoms, pain catastrophizing, and sleep quality. Results suggested that observed racial/ethnic differences in AA women's pain intensity, pain interference, and common risk factors for elevated pain may be largely due to racial/ethnic differences in SES. These findings highlight the role of social inequality in persistent health disparities facing inner-city, AA women.

Racial/ethnic differences in experimental pain sensitivity and associated factors - Cardiovascular responsiveness and psychological status

This study evaluated the contributions of psychological status and cardiovascular responsiveness to racial/ethnic differences in experimental pain sensitivity. The baseline measures of 3,159 healthy individuals-non-Hispanic white (NHW): 1,637, African-American (AA): 1,012, Asian: 299, and Hispanic: 211-from the OPPERA prospective cohort study were used. Cardiovascular responsiveness measures and psychological status were included in structural equation modeling based mediation analyses. Pain catastrophizing was a significant mediator for the associations between race/ethnicity and heat pain tolerance, heat pain ratings, heat pain aftersensations, mechanical cutaneous pain ratings and aftersensations, and mechanical cutaneous pain temporal summation for both Asians and AAs compared to NHWs. HR/MAP index showed a significant inconsistent (mitigating) mediating effect on the association between race/ethnicity (AAs vs. NHWs) and heat pain tolerance. Similarly, coping inconsistently mediated the association between race/ethnicity and mechanical cutaneous pain temporal summation in both AAs and Asians, compared to NHWs. The factor encompassing depression, anxiety, and stress was a significant mediator for the associations between race/ethnicity (Asians vs. NHWs) and heat pain aftersensations. Thus, while pain catastrophizing mediated racial/ethnic differences in many of the QST measures, the psychological and cardiovascular mediators were distinctly restrictive, signifying multiple independent mechanisms in racial/ethnic differences in pain.

Race, psychosocial vulnerability and social support differences in inner-city women's symptoms of posttraumatic stress disorder

BACKGROUND/OBJECTIVES

Inner-city Black women may be more susceptible to posttraumatic stress disorder (PTSD) than White women, although mechanisms underlying this association are unclear. Living in urban neighborhoods distinguished by higher chronic stress may contribute to racial differences in women's cognitive, affective, and social vulnerabilities, leading to greater trauma-related distress including PTSD. Yet social support could buffer the negative effects of psychosocial vulnerabilities on women's health.

METHODS/DESIGN

Mediation and moderated mediation models were tested with 371 inner-city women, including psychosocial vulnerability (i.e., catastrophizing, anger, social undermining) mediating the pathway between race and PTSD, and social support moderating psychosocial vulnerability and PTSD.

RESULTS

Despite comparable rates of trauma, Black women reported higher vulnerability and PTSD symptoms, and lower support compared to White Hispanic and non-Hispanic women. Psychosocial vulnerability mediated the pathway between race and PTSD, and social support moderated vulnerability, reducing negative effects on PTSD. When examining associations by race, the moderation effect remained significant for Black women only.

CONCLUSIONS

Altogether these psychosocial vulnerabilities represent one potential mechanism explaining Black women's greater risk of PTSD, although cumulative psychosocial vulnerability may be buffered by social support. Despite higher support, inner-city White women's psychosocial vulnerability may actually outweigh support's benefits for reducing trauma-related distress.

Psychological and Genetic Predictors of Pain Tolerance

Previous studies have shown associations between genetic polymorphisms and pain tolerance, but psychological evaluations are seldom measured. The objective of this study was to determine the independent effects of demographic, psychological, and genetic predictors of cold noxious pain tolerance. Healthy subjects (n = 89) completed the Pain Catastrophizing Scale (PCS) and Fear of Pain Questionnaire (FPQ‐III), underwent genotyping for candidate single nucleotide polymorphisms (SNPs), and completed a cold‐pressor test in a 1–2°C water bath for a maximum of 3 minutes. The primary outcome measure was pain tolerance, defined as the maximum duration of time subjects left their nondominant hand in the cold‐water bath. Cox proportional hazards regression indicated that female sex, Asian race, and increasing PCS and FPQ‐III scores were associated with lower pain tolerance. No candidate SNP was significantly associated with pain tolerance. Future genetic studies should include demographic and psychological variables as confounders in experimental pain models.

Machine learning methods for automatic pain assessment using facial expression information: Protocol for a systematic review and meta-analysis

INTRODUCTION

Prediction of pain using machine learning algorithms is an emerging field in both computer science and clinical medicine. Several machine algorithms were developed and validated in recent years. However, the majority of studies in this topic was published on bioinformatics or computer science journals instead of medical journals. This tendency and preference led to a gap of knowledge and acknowledgment between computer scientists who invent the algorithm and medical researchers who may use the algorithms in practice. As a consequence, some of these prediction papers did not discuss the clinical utility aspects and were causally reported without following related professional guidelines (e.g., TRIPOD statement). The aim of this protocol is to systematically summarize the current evidences about performance and utility of different machine learning methods used for automatic pain assessments based on human facial expression. In addition, this study is aimed to demonstrate and fill the knowledge gap to promote interdisciplinary collaboration.

METHODS AND ANALYSIS

We will search all English language literature in the following electronic databases: PubMed, Web of Science and IEEE Xplore. A systematic review and meta-analysis summarizing the accuracy, interpretability, generalizability, and computational efficiency of machine learning methods will be conducted. Subgroup analyses by machine learning method types will be conducted.

TIMELINE

The formal meta-analysis will start on Jan 15, 2019 and expected to finish by April 15, 2019.

ETHICS AND DISSEMINATION

Ethical approval will be exempted or will not be required because the data collected and analyzed in this meta-analysis will not be on an individual level. The results will be disseminated in the form of an official publication in a peer-reviewed journal and/or presentation at relevant conferences.

REGISTRATION

PROSPERO CRD42018103059.

Gender, genetics, and analgesia: understanding the differences in response to pain relief

Genetic variations and gender contribute significantly to the large interpatient variations in opioid-related serious adverse effects and differences in pain relief with other analgesics. Opioids are the most commonly used analgesics to relieve moderate-to-severe postoperative pain. Narrow therapeutic index and unexplained large interpatient variations in opioid-related serious adverse effects and analgesia negatively affect optimal perioperative outcomes. In surgical, experimental, chronic, and neuropathic pain models, females have been reported to have more pain than males. This review focuses on literature evidence of differences in pain relief due to multiple genetic variations and gender of the patient.