Multiethnic differences in responses to laboratory pain stimuli among children

Effects of different types of neonatal pain on somatosensory and cognitive development in male juvenile rats

BACKGROUND

Premature infants are inevitably exposed to painful events, including repetitive procedures, inflammation, or mixed stimulation that may induce long-term behavioral outcomes. Here, we set up three neonatal painful models to investigate their long-term effect on somatosensation and cognition.

METHODS

Three types of neonatal pain models in rat were set up. Rat pups were randomly assigned to four groups. The needling pain (NP) group received repetitive needle pricks on the paws from the day of birth (PD0) to postnatal day 7 (PD7) to mimic the diagnostic and therapeutic procedures. The inflammatory pain (IP) group received the injection of carrageenan into the left hindpaw at PD3 to induce IP in peripheral tissues. The mixed pain group received a combination of the NP and IP (NIP). The control (CON) group was untreated. We performed behavioral and biochemical testing of juvenile rats (PD21-PD26).

RESULTS

The NIP group showed a longer hypersensitivity than the NP group, when given a secondary inflammatory stimulation. NP led to insensitivity to anxiety-causing stimuli and impairment of fear memory both aggravated by NIP. NP reduced the expression of synapse-related molecules (GluN1/PSD95/GFAP) in the medial prefrontal cortex, and NIP exacerbated this decrease. The corticosterone secretion in the NIP group increased after the behavioral task, compared with those in other three groups.

CONCLUSION

A combination of NP with inflammation occurring in the neonatal period might aggravate the adverse effects of each on somatosensory and cognitive development of rats, the mechanism of which might be associated with the increase of corticosterone secretion and the dysregulation of synaptic molecules.

The Impact of Primary Language Spoken on the Pain Experience of Children With Cancer

The purpose of the current prospective cohort study was to determine if acculturation, measured by primary language spoken, impacts the pain response of children being treated for cancer during an experimental pain task. Sixty-seven Spanish-speaking and English-speaking children ages 6 to 18 years being treated for cancer provided ratings of pain and upset severity during the completion of the cold pressor task (CPT). One week following the CPT, participants provided their recollection of average pain and upset during the CPT. Repeated measures analysis of variance revealed Spanish-speaking children reported significantly higher pain (F1,64=5.58, P=0.02) and upset (F1,64=7.69, P=0.007) ratings during the CPT compared with English-speaking children. Also, Spanish-speaking children were over 4 times as likely to remove their hands from the water before the CPT 4-minute uninformed ceiling compared with English-speaking children (P=0.002). These findings suggest that cultural and contextual factors, including the level of acculturation, are important considerations in the assessment and management of pain in children with cancer. Future research should continue to examine the mechanisms underlying the association between acculturation and the symptom experience for children receiving treatment for cancer.

Persistent Incisional Pain after Noncardiac Surgery: An International Prospective Cohort Study

BACKGROUND

The purpose of this study was to determine the incidence, characteristics, impact, and risk factors associated with persistent incisional pain. The hypothesis was that patient demographics and perioperative interventions are associated with persistent pain.

METHODS

This was a secondary analysis of an international prospective cohort study from 2012 to 2014. This study included patients who were 45 yr of age or older who underwent major inpatient noncardiac surgery. Data were collected perioperatively and at 1 yr after surgery to assess for the development of persistent incisional pain (pain present around incision at 1 yr after surgery).

RESULTS

Among 14,831 patients, 495 (3.3%; 95% CI, 3.1 to 3.6) reported persistent incisional pain at 1 yr, with an average pain intensity of 3.6 ± 2.5 (0 to 10 numeric rating scale), with 35% and 14% reporting moderate and severe pain intensities, respectively. More than half of patients with persistent pain reported needing analgesic medications, and 85% reported interference with daily activities (denominator = 495 in the above proportions). Risk factors for persistent pain included female sex (P = 0.007), Asian ethnicity (P < 0.001), surgery for fracture (P < 0.001), history of chronic pain (P < 0.001), coronary artery disease (P < 0.001), history of tobacco use (P = 0.048), postoperative patient-controlled analgesia (P < 0.001), postoperative continuous nerve block (P = 0.010), insulin initiation within 24 h of surgery (P < 0.001), and withholding nonsteroidal anti-inflammatory medication or cyclooxygenase-2 inhibitors on the day of surgery (P = 0.029 and P < 0.001, respectively). Older age (P < 0.001), endoscopic surgery (P = 0.005), and South Asian (P < 0.001), Native American/Australian (P = 0.004), and Latin/Hispanic ethnicities (P < 0.001) were associated with a lower risk of persistent pain.

CONCLUSIONS

Persistent incisional pain is a common complication of inpatient noncardiac surgery, occurring in approximately 1 in 30 adults. It results in significant morbidity, interferes with daily living, and is associated with persistent analgesic consumption. Certain demographics, ethnicities, and perioperative practices are associated with increased risk of persistent pain.

EDITOR’S PERSPECTIVE

Relationship between Acculturative Stress and Pain Catastrophizing in Korean Americans

Acculturative stress is speculated to be a sociocultural factor contributing to pain since cultural beliefs and practices can influence the way patients perceive and respond to pain. However, the relationship between acculturative stress and pain catastrophizing remains poorly understood. Therefore, we examined the relationship between acculturative stress and pain catastrophizing in Korean Americans. We collected survey data from Korean American in Texas (N = 374). Acculturative stress was measured with the Acculturative Stress Scale, and pain catastrophizing was measured with the Pain Catastrophizing Scale. Participants' mean age was 46.89 years, and 63% were women. Bivariate and multivariate statistical analyses indicated that higher acculturative stress may contribute to higher pain catastrophizing (regression coefficient = 1.02, P = 0.04). These findings advance our understanding of sociocultural factors associated with pain in Korean Americans; additional research with a larger sample is warranted for cross-validation.

Placebo hypoalgesia: racial differences

No large-cohort studies that examine potential racial effects on placebo hypoalgesic effects exist. To fill this void, we studied placebo effects in healthy and chronic pain participants self-identified as either African American/black (AA/black) or white. We enrolled 372 study participants, 186 with a diagnosis of temporomandibular disorder (TMD) and 186 race-, sex-, and age-matched healthy participants to participate in a placebo experiment. Using a well-established paradigm of classical conditioning with verbal suggestions, each individual pain sensitivity was measured to calibrate the temperatures for high- and low-pain stimuli in the conditioning protocol. These 2 temperatures were then paired with a red and green screen, respectively, and participants were told that the analgesic intervention would activate during the green screens to reduce pain. Participants then rated the painfulness of each stimulus on a visual analog scale ranging from 0 to 100. Racial influences were tested on conditioning strength, reinforced expectations, and placebo hypoalgesia. We found that white participants reported greater conditioning effects, reinforced relief expectations, and placebo effects when compared with their AA/black counterparts. Racial effects on placebo were observed in TMD, although negligible, short-lasting, and mediated by conditioning strength. Secondary analyses on the effect of experimenter-participant race and sex concordance indicated that same experimenter-participant race induced greater placebo hypoalgesia in TMDs while different sex induced greater placebo hypoalgesia in healthy participants. This is the first and largest study to analyze racial effects on placebo hypoalgesia and has implications for both clinical research and treatment outcomes.

Association Between Race and Ethnicity with Intraoperative Analgesic Administration and Initial Recovery Room Pain Scores in Pediatric Patients: a Single-Center Study of 21,229 Surgeries

INTRODUCTION

Perioperative pain may have deleterious effects for all patients. We aim to examine disparities in pain management for children in the perioperative period to understand whether any racial and ethnic groups are at increased risk of poor pain control.

METHODS

Medical records from children ≤ 18 years of age who underwent surgery from May 2014 to May 2018 were reviewed. The primary outcome was total intraoperative morphine equivalents. The secondary outcomes were intraoperative non-opioid analgesic administration and first conscious pain score. The exposure was race and ethnicity. The associations of race and ethnicity with outcomes of interest were modeled using linear or logistic regression, adjusted for preselected confounders and covariates. Bonferroni corrections were made for multiple comparisons.

RESULTS

A total of 21,229 anesthetics were included in analyses. In the adjusted analysis, no racial and ethnic group received significantly more or less opioids intraoperatively than non-Hispanic (NH) whites. Asians, Hispanics, and Pacific Islanders were estimated to have significantly lower odds of receiving non-opioid analgesics than NH whites: odds ratio (OR) = 0.83 (95% confidence interval (CI): 0.70, 0.97); OR = 0.84 (95% CI: 0.74, 0.97), and OR = 0.53 (95% CI: 0.33, 0.84) respectively. Asians were estimated to have significantly lower odds of reporting moderate-to-severe pain on awakening than NH whites: OR = 0.80 (95% CI: 0.66, 0.99).

CONCLUSIONS

Although children of all races and ethnicities investigated received similar total intraoperative opioid doses, some were less likely to receive non-opioid analgesics intraoperatively. Asians were less likely to report moderate-severe pain upon awakening. Further investigation may delineate how these differences lead to disparate patient outcomes and are influenced by patient, provider, and system factors.

Quantitative Sensory Testing in Adolescents with Co-occurring Chronic Pain and Obesity: A Pilot Study

Factors such as gender, ethnicity, and age affect pain processing in children and adolescents with chronic pain. Although obesity has been shown to affect pain processing in adults, almost nothing is known about pediatric populations. The aim of this pilot study was to explore whether obesity alters sensory processing in adolescents with chronic pain. Participants were recruited from a chronic pain clinic (Chronic Pain (CP), n = 12 normal weight; Chronic Pain + Obesity (CPO), n = 19 overweight/obesity) and from an obesity clinic (Obesity alone (O), n = 14). The quantitative sensory testing protocol included assessments of thermal and mechanical pain thresholds and perceptual sensitization at two sites with little adiposity. The heat pain threshold at the hand was significantly higher in the CPO group than in either the CP or O groups. Mechanical pain threshold (foot) was significantly higher in the CPO group than the CP group. No differences were found on tests of perceptual sensitization. Correlations between experimental pain and clinical pain parameters were found for the CPO group, but not for the CP group. This preliminary study provides important lessons learned for subsequent, larger-scale studies of sensory processing for youth with co-occurring chronic pain and obesity.

Assessing peripheral fibers, pain sensitivity, central sensitization, and descending inhibition in Native Americans: main findings from the Oklahoma Study of Native American Pain Risk

Native Americans (NAs) have a higher prevalence of chronic pain than other U.S. racial/ethnic groups, but there have been few attempts to understand the mechanisms of this pain disparity. This study used a comprehensive battery of laboratory tasks to assess peripheral fiber function (cool/warm detection thresholds), pain sensitivity (eg, thresholds/tolerances), central sensitization (eg, temporal summation), and pain inhibition (conditioned pain modulation) in healthy, pain-free adults (N = 155 NAs, N = 150 non-Hispanic Whites [NHWs]). Multiple pain stimulus modalities were used (eg, cold, heat, pressure, ischemic, and electric), and subjective (eg, pain ratings and pain tolerance) and physiological (eg, nociceptive flexion reflex) outcomes were measured. There were no group differences on any measure, except that NAs had lower cold-pressor pain thresholds and tolerances, indicating greater pain sensitivity than NHWs. These findings suggest that there are no group differences between healthy NAs and NHWs on peripheral fiber function, central sensitization, or central pain inhibition, but NAs may have greater sensitivity to cold pain. Future studies are needed to examine potential within-group factors that might contribute to NA pain risk.

Pain-related anxiety promotes pronociceptive processes in Native Americans: bootstrapped mediation analyses from the Oklahoma Study of Native American Pain Risk

INTRODUCTION

Evidence suggests Native Americans (NAs) experience higher rates of chronic pain than the general US population, but the mechanisms contributing to this disparity are poorly understood. Recently, we conducted a study of healthy, pain-free NAs (n = 155), and non-Hispanic whites (NHWs, n = 150) to address this issue and found little evidence that NAs and NHWs differ in pain processing (assessed from multiple quantitative sensory tests). However, NAs reported higher levels of pain-related anxiety during many of the tasks.

OBJECTIVE

The current study is a secondary analysis of those data to examine whether pain-related anxiety could promote pronociceptive processes in NAs to put them at chronic pain risk.

METHODS

Bootstrapped indirect effect tests were conducted to examine whether pain-related anxiety mediated the relationships between race (NHW vs NA) and measures of pain tolerance (electric, heat, ischemia, and cold pressor), temporal summation of pain and the nociceptive flexion reflex (NFR), and conditioned pain modulation of pain/NFR.

RESULTS

Pain-related anxiety mediated the relationships between NA race and pain tolerance and conditioned pain modulation of NFR. Exploratory analyses failed to show that race moderated relationships between pain-related anxiety and pain outcomes.

CONCLUSION

These findings imply that pain-related anxiety is not a unique mechanism of pain risk for NAs, but that the greater tendency to experience pain-related anxiety by NAs impairs their ability to engage descending inhibition of spinal nociception and decreases their pain tolerance (more so than NHWs). Thus, pain-related anxiety may promote pronociceptive processes in NAs to place them at risk for future chronic pain.

Gender differences in adolescents' perceptions toward dentists using the Japanese version of the dental beliefs survey: a cross-sectional survey

Background

While adult women show greater dental anxiety than adult men, few studies have examined gender differences in adolescent perceptions of dentists. Therefore, this cross-sectional study aimed to evaluate the gender differences in adolescents’ perceptions toward dentists by using the Japanese version of the Dental Beliefs Survey (DBS) and the factor structure of the DBS.

Methods

We conducted surveys at schools, and 957 Japanese adolescents (403 girls and 554 boys, aged between 13 and 15 years) participated in this study. To assess their confidence in dentists, participants were asked to complete the self-reported, 15-item Japanese version of the DBS. We performed a Welch’s t-test and a one-way analysis of variance to assess differences in DBS scores by gender and age. Factor analysis (principal components, varimax rotation) was used to assess the scale’s factor structure.

Results

A significant gender difference was observed in the DBS scores (P = 0.018), suggesting that boys exhibit greater negative perceptions toward the behavior of dentists than girls. However, there was no significant difference found among ages. The factor analysis yielded two results: Factor 1, “trust” (seven items); and Factor 2, “lack of control” (five items). Notably, the factor structure differed according to gender. As such, by including only factors with eigenvalues above 1.0, the DBS for girls comprised “trust” (seven items) and “communication” (three items), while that for boys comprised “lack of control” (six items) and “belittlement” (six items).

Conclusions

This study identified two factors of differing strengths pertaining to the confidence of Japanese adolescents in dentists. Gender differences in perceptions toward dentists were observed. Accounting for these differences may improve the effectiveness of strategies to lower dental anxiety and foster positive dental beliefs in young patients.

The Relationship between Acculturation and Experimental Pain Sensitivity in Asian Americans with Knee Osteoarthritis

Multiple studies in healthy populations and clinical samples have shown that ethnic minorities have greater pain sensitivity than their majority counterparts. Acculturation is speculated to be one of the sociocultural factors contributing to pain sensitivity since cultural beliefs and practices can influence the way patients perceive and respond to pain. However, the relationship of acculturation to pain sensitivity in minority populations remains poorly understood. Therefore, in this cross-sectional study, we examined the relationship between acculturation and experimental pain sensitivity in 50 Asian Americans residing in North Central Florida with knee osteoarthritis pain. The Suinn-Lew Asian Self Identity Acculturation Scale was used to assess acculturation, and multimodal quantitative sensory testing was performed to measure experimental sensitivity, including heat pain tolerance, pressure pain threshold, and punctate mechanical pain. Descriptive and regression analyses were performed. Participants' mean age was 55.7 years, and about half of this sample were Korean American (56%). The participants had lived in the United States for 21 years on average. Regression analyses indicated that lower acculturation to American culture may contribute to greater experimental pain sensitivity. Asian Americans who were more acculturated to the American culture had higher heat pain tolerance (beta = 0.61, P=0.01), higher pressure pain threshold (beta = 0.59, P=0.02), and lower ratings of punctate mechanical pain (beta = -0.70, P < 0.01). These findings add to the literature regarding sociocultural factors associated with pain in Asian Americans; additional research with a larger and more diverse sample of Asian Americans is warranted for cross-validation.

Ethnic Differences Identified by Pain Sensitivity Questionnaire Correlate With Clinical Pain Responses

BACKGROUND AND OBJECTIVES

The Pain Sensitivity Questionnaire, English version (PSQ-E), is predictive of pain-related responses to experimental stimuli. Ethnic differences have been noted in experimental measures of pain sensation using quantitative sensory testing. The present study sought to determine if the PSQ-E also identified similar ethnic differences.

METHODS

Fifty-seven subjects who self-identified as African Americans (AAs) and who were scheduled to undergo a low-back interventional procedure completed the PSQ-E and other questionnaires. Their data were compared with an age-, sex-, and opioid usage-matched sample of 57 self-identified non-Hispanic white (NHW) subjects. Pain ratings on a visual analog scale (VAS) were obtained following 2 standardized injections of subcutaneous lidocaine (VAS1-infiltration in hand, VAS2-infiltration of procedural site). Correlations between PSQ-E scores, VAS measures, and other inventories were tested.

RESULTS

The PSQ-E scores and clinical and experimental pain scores were all significantly elevated in AA compared with NHW patients (P < 0.05 for experimental pain scores, P < 0.001 for PSQ and clinical pain scores). Measures of pain interference, depression, anxiety, and pain catastrophizing were not different between groups. Similar to our previous study, PSQ-E scores significantly correlated with both experimental and clinical pain scores (eg, PSQ-E with Brief Pain Inventory pain score: r = 0.39, P < 0.001).

CONCLUSIONS

The study demonstrated significantly elevated pain sensitivity in AA compared with NHW patients as measured by the PSQ-E and experimental and clinical pain intensity scores. This shows that the PSQ reflects the known elevation of pain sensitivity in AA subjects and suggests that it may be useful in assessing pain treatment disparities by identifying and standardizing differences in pain sensitivity.

Kinds of individuals defined by patterns of variables

This paper argues that investigators should consider replacing the popular practice of comparing individuals varying in gender, social class, and/or ethnicity on one or more continuous measures with a search for kinds of individuals defined by patterns of properties that include not only their values on outcome measures but also their gender, social class, and ethnicity. Investigators who believe that a particular predictor contributes to an outcome independent of the gender, class, or ethnicity of the participants often implement statistical procedures that promise to remove the contributions of the above categories. These analyses lead to misleading conclusions when the controlled category is correlated with the dependent measures. The final sections summarize the properties of genders, classes, and ethnic groups that make distinctive contributions to many psychological outcomes. The paper ends by noting that a society's ethical beliefs constitute a defensible basis for ignoring the biological properties associated with these categories in order to allow members of these groups access to whatever educational or occupational goals they desire.

Depression and Pain in Asian and White Americans With Knee Osteoarthritis

Few studies have examined the underlying psychosocial mechanisms of pain in Asian Americans. Using the biopsychosocial model, we sought to determine whether variations in depression contribute to racial group differences in symptomatic knee osteoarthritis pain between Asian Americans and non-Hispanic white Americans. The sample consisted of 100 participants, including 50 Asian Americans (28 Korean Americans, 9 Chinese Americans, 7 Japanese Americans, 5 Filipino Americans, and 1 Indian American) and 50 age- and sex-matched non-Hispanic white Americans with symptomatic knee osteoarthritis pain. The Centers for Epidemiologic Studies Depression Scale was used to assess symptoms of depression, and the Western Ontario and McMaster Universities Osteoarthritis Index and the Graded Chronic Pain Scale were used to measure clinical pain. In addition, quantitative sensory testing was used to measure experimental sensitivity to heat- and mechanically-induced pain. The results indicated that higher levels of depression in Asian Americans may contribute to greater clinical pain and experimental pain sensitivity. These findings add to the growing literature regarding ethnic and racial differences in pain and its associated psychological conditions, and additional research is warranted to strengthen these findings.

PERSPECTIVE

This article shows the contribution of depression to clinical pain and experimental pain sensitivity in Asian Americans with knee osteoarthritis. Our results suggest that Asian Americans have higher levels of depressive symptoms and that depression plays a relevant role in greater clinical pain and experimental pain sensitivity in Asian Americans.

Acculturation matters in the relation between ambivalence over emotional expressions and well-being among Chinese American breast cancer survivors

PURPOSE

Ambivalence over emotional expression (AEE) is the inner conflict of desiring emotion expression and fearing consequence of emotion expression. Few studies to date have examined the effects of AEE within an ethnic group that prioritizes emotional self-control. The present study examined the associations between AEE and well-being (viz., quality of life and depressive symptoms) as a function of acculturation among a sample of Chinese American breast cancer survivors.

METHODS

Ninety-six Chinese breast cancer survivors (M _age = 54.64 years old, SD = 7.98) were recruited from Southern California. Participants filled out a paper-pen questionnaire containing the Ambivalence over Emotional Expression Questionnaire (AEQ), the Functional Assessment of Cancer Therapy-Breast (FACT-B), and the Center for Epidemiologic Studies Depression Scale-Short Form (CESD-10).

RESULTS

Acculturation was a statistically significant moderator of the relations between AEE and depressive symptoms, and a statistically marginally significant moderator of the relations between AEE and quality of life. Simple slopes revealed that AEE was negatively associated with quality of life (B = -.45, p < .001) and depressive symptoms (B = .20, p < .001) for women with high acculturation, but not associated for women with low acculturation (Bs = -.15 and .04, ps > .05, for quality of life and depressive symptoms, respectively).

CONCLUSIONS

These results suggest that less acculturated Chinese breast cancer survivors are protected by Chinese cultural values of emotional self-control and restraint, and thus do not experience the detrimental effects of AEE on their depressive symptoms and quality of life. Implications are discussed.

Using a cultural and RDoC framework to conceptualize anxiety in Asian Americans

Asian Americans are one of the fastest growing minority groups in the United States; however, mental health within this population segment, particularly anxiety disorders, remains significantly understudied. Both the heterogeneity within the Asian American population and the multidimensional nature of anxiety contribute to difficulties in understanding anxiety in this population. The present paper reviewed two sources of heterogeneity within anxiety in Asian Americans: (1) cultural variables and (2) mechanisms or components of anxiety. Specifically, we examined four cultural variables most commonly found in research related to anxiety in Asian Americans: acculturation, loss of face, affect valuation, and individualism-collectivism. We also discussed ways to parse anxiety through a Research Domain Criteria (RDoC) framework, specifically focusing on sensitivity to acute and potential threat, constructs within the Negative Valence System. Previously unpublished preliminary data were presented to illustrate one way of examining ethnic differences in anxiety using an RDoC framework. Finally, this paper offered recommendations for future work in this area.

Accounting for Ethnicity-Related Differences in Ocular Surface Integrity as a Step Toward Understanding Contact Lens Discomfort

Contact lens discomfort is a common problem that can lead to unsuccessful or limited contact lens wear. Although many factors may contribute to contact lens discomfort, limited research has explored the influence of ethnicity-related differences in the anatomy and physiology of the ocular surface. Therefore, we performed a search of the literature in PubMed using key words related to "ocular surface" paired with the terms "race" and "ethnicity." The goal of this review was to determine potential areas of research regarding ethnicity differences, particularly between Asian and non-Asian eyes, in ocular surface integrity to advance our understanding of contact lens discomfort.

Differences in Clinical Pain and Experimental Pain Sensitivity Between Asian Americans and Whites With Knee Osteoarthritis

OBJECTIVE

Ethnicity has been associated with clinical and experimental pain responses. Whereas ethnic disparities in pain in other minority groups compared with whites are well described, pain in Asian Americans remains poorly understood. The purpose of this study was to characterize differences in clinical pain intensity and experimental pain sensitivity among older Asian American and non-Hispanic white (NHW) participants with knee osteoarthritis (OA).

METHODS

Data were collected from 50 Asian Americans ages 45 to 85 (28 Korean, 9 Chinese, 7 Japanese, 5 Filipino, and 1 Indian) and compared with 50 age-matched and sex-matched NHW individuals with symptomatic knee OA pain. The Western Ontario and McMaster Universities Osteoarthritis Index and Graded Chronic Pain Scale were used to assess the intensity of clinical knee pain. In addition, quantitative sensory testing was used to measure experimental sensitivity to heat-induced and mechanically induced pain.

RESULTS

Asian American participants had significantly higher levels of clinical pain intensity than NHW participants with knee OA. In addition, Asian American participants had significantly higher experimental pain sensitivity than NHW participants with knee OA.

DISCUSSION

These findings add to the growing literature regarding ethnic and racial differences in clinical pain intensity and experimental pain sensitivity. Asian Americans in particular may be at risk for clinical pain and heightened experimental pain sensitivity. Further investigation is needed to identify the mechanisms underlying ethnic group differences in pain between Asian Americans and NHWs, and to ensure that ethnic group disparities in pain are ameliorated.

A meta-analysis on pain sensitivity in self-injury

Individuals engaging in self-injurious behavior (SIB) frequently report absence of pain during acts of SIB. While altered pain sensitivity is discussed as a risk factor for the engagement in SIB, results have been mixed with considerable variance across reported effect sizes, in particular with respect to the effect of co-morbid psychopathology. The present meta-analysis aimed to summarize the current evidence on pain sensitivity in individuals engaging in SIB and to identify covariates of altered pain processing. Three databases were searched without restrictions. Additionally a hand search was performed and reference lists of included studies were checked for potential studies eligible for inclusion. Thirty-two studies were identified after screening 720 abstracts by two independent reviewers. Studies were included if they reported (i) an empirical investigation, in (ii) humans, including a sample of individuals engaging in (iii) SIB and a group of (iv) healthy controls, (v) receiving painful stimulation. Random-effects meta-analysis was performed on three pain-related outcomes (pain threshold, pain tolerance, pain intensity) and several population- and study-level covariates (i.e. age, sex, clinical etiology) were subjected to meta-regression. Meta-analysis revealed significant main effects associated with medium to large effect sizes for all included outcomes. Individuals engaging in SIB show greater pain threshold and tolerance and report less pain intensity compared to healthy controls. Clinical etiology and age are significant covariates of pain sensitivity in individuals engaging in SIB, such that pain threshold is further increased in borderline personality disorder compared to non-suicidal self-injury. Mechanisms underlying altered pain sensitivity are discussed.

Understanding Ocular Discomfort and Dryness Using the Pain Sensitivity Questionnaire

PURPOSE

To utilize the Pain Sensitivity Questionnaire (PSQ) to assess the influence of pain sensitivity on perceptions of ocular discomfort and dryness.

METHODS

Subjects completed a battery of questionnaires, including history of ocular and general health, contact lens wear history, the Ocular Surface Disease Index (OSDI) questionnaire, visual analog scale (VAS) 100-point rating scales to assess severity and frequency of average and end of day (EOD) discomfort and dryness, and the PSQ to assess pain sensitivity level. Masked subjects were then instructed to wear one inverted and one normally oriented soft contact lens contralaterally for 30 minutes to induce an inter-eye difference in comfort and dryness sensations. Subjects rated comfort and dryness in each eye on VAS every 5 minutes during contact lens wear. A slit lamp examination was performed to evaluate ocular surface health and to assess contact lens fit.

RESULTS

One hundred and fifty-three subjects (111 females, 42 males) completed the study. In separate models, a higher PSQ score was significantly associated with higher OSDI score (p = 0.002), lower average and EOD comfort (p = 0.005 and 0.001, respectively), and greater EOD dryness (p = 0.04). The minimum (0.14) and maximum (7.14) PSQ scores observed in our subject cohort (i.e., from the subjects who were the least and most sensitive to pain, respectively) corresponded to an estimated difference of 11 points on the OSDI, 20 points on the VAS scale for average comfort, 31 points for EOD comfort and 17 points for EOD dryness. In a mixed effects model, a higher PSQ score was significantly associated with a greater inter-eye difference in comfort (p = 0.013) and dryness (p = 0.010) during CL wear.

CONCLUSIONS

Pain sensitivity influences perceptions of ocular discomfort and dryness, and should be taken into account when evaluating subjective assessments of these symptoms.

Race Effects on Conditioned Pain Modulation in Youth

Race and ethnicity shape the experience of pain in adults. African Americans typically exhibit greater pain intensity and evoked pain responsiveness than non-Hispanic whites. However, it remains unclear whether there are racial differences in conditioned pain modulation (CPM) and if these are present in youth. CPM refers to a reduction in perceived pain intensity for a test stimulus during application of a conditioning stimulus and may be especially relevant in determining risk for chronic pain. The present study assessed CPM to evoked thermal pain in 78 healthy youth (ages 10-17 years), 51% of whom were African American and 49% of whom were non-Hispanic white. African American youth reported lower mean conditioning pain ratings than non-Hispanic white youth, controlling for mean preconditioning pain ratings, which is consistent with stronger CPM. Multilevel models demonstrated stronger CPM effects in African American than non-Hispanic white youth, as evident in more rapid within-person decreases in pain ratings during the conditioning phase. These findings suggest that diminished CPM likely does not account for the enhanced responsiveness to evoked thermal pain observed in African American youth. These results may have implications for understanding racial differences in chronic pain experienced in adulthood. Perspective: This study evaluated conditioned pain modulation to evoked thermal pain in African American and non-Hispanic white youth. Findings could have implications for the development of personalized chronic pain treatment strategies that are informed by race and ethnicity.

The psychological impact of eyedrops administration in children

PURPOSE

To determine the psychological effects of eyedrops administration in children.

METHODS

Children requiring eyedrops for cycloplegic refraction were recruited in this cross-sectional study. Nurses administered eyedrops in 2-3 cycles spaced 5-10 minutes apart, and optometrists performed refraction 30 minutes after the last drop. Ophthalmologists, nurses, and optometrists rated the children's cooperation level at first review, after each eyedrop, at refraction, and at final review. Parents chose a personality type best describing their child, and monitored their child's anxiety using a modified Yale Preoperative Anxiety Scale (m-YPAS). Children were "uncooperative" if nurses noted significant distress during the first drop cycle.

RESULTS

A total of 298 children 2-12 years of age were included. Of these, 77 (26%) experienced pre-drop distress and 39 (13%) were uncooperative with drops. Compared to cooperative children, uncooperative children tended to be younger (2.0-4.9 years vs ≥8 years; OR, 4.11; 95% CI, 1.14-14.83; P = 0.031), male (OR, 2.55; 95% CI, 1.06-6.10; P = 0.036), have had a previous negative eyedrop experience (84.2% vs 25.3%; P < 0.001) and were more anxious (m-YPAS scores, 41.4 ± 22.0 vs 30.6 ± 12.6: P < 0.001). Children described as "demanding and aggressive" were more uncooperative than "timid and anxious" children. It took longer to instill drops (3.1 vs 1.3 minutes), and perform refraction (11.6 vs 7.2 minutes) in uncooperative children.

CONCLUSIONS

A small group of children were uncooperative with eyedrops and 26% experienced significant pre-drop anxiety. Factors such as age, sex, a previous negative eyedrop experience, and pre-drop anxiety, associated with uncooperativeness need to be considered when developing strategies to improve the eyedrops experience in children.

The Curse of Curves: Sex Differences in the Associations Between Body Shape and Pain Expression

This study examines the associations between objective and subjective measurements and impressions of body shape and cold pressor pain reporting in healthy adults. On the basis of sexual selection theory (SST), we hypothesized that body characteristics that are universally preferred by the opposite sex-specifically, lower waist-to-hip ratios (WHR) in women and higher shoulder-to-hip ratios (SHR) in men-and characteristics (e.g., proportion of body fat in women) that infer attractiveness differently across cultures will correspond to higher experimental pain reporting in women and lower pain reporting in males. A convenience sample of young adults (n = 96, 58 females, 18-24 years; mean age = 19.4) was measured for body mass index (BMI), WHR, SHR, and subjective body impressions (SBI), along with cold pressor pain reporting. The findings showed that BMI was positively associated with WHR and less-positive SBI in both sexes. Consistent with SST, however, only BMI and WHR predicted variability in pain expression in women, whereas only SHR predicted variability in men. Subjective body impressions were positively associated with SHR among males and unrelated to WHR among females, yet only females showed a positive association between SBI and higher pain reporting. The findings suggest that sexually selected physical characteristics (WHR and SHR) and culturally influenced somatic (BMI) and psychological (SBI) indicators of attractiveness correspond with variability in pain reporting, potentially reflecting the general tendency for people to express clusters of sexually selected and culturally influenced traits that may include differential pain perception.

Race effects on temporal summation to heat pain in youth

Racial differences in pain responsiveness have been demonstrated in adults. However, it is unclear whether racial differences are also present in youth and whether they extend to experimental pain indices assessing temporal summation of second pain (TSSP). Temporal summation of second pain provides an index of pain sensitivity and may be especially relevant in determining risk for chronic pain. This study assessed pain tolerance and TSSP to evoked thermal pain in 78 healthy youth (age range, 10-17), 51% of whom were African American and 49% were non-Hispanic white. Multilevel models revealed within-individual increases in pain ratings during the temporal summation task in non-Hispanic white youth that were consistent with TSSP. Pain ratings did not change significantly during the temporal summation task in African-American youth. Baseline evoked pain ratings were significantly higher in African-American compared with non-Hispanic white youth. These findings suggest that enhanced responsiveness to evoked thermal pain in African Americans is present in adolescence but is unlikely to be related to elevated TSSP. These results may have implications for understanding racial differences in chronic pain experience in adulthood.

A comparative study of 10% KOH solution and 5% imiquimod cream for the treatment of Molluscum contagiosum in the pediatric age group

Background:

Although Molluscum contagiosum (MC) is a self-limiting condition, active therapy could prevent further spread and improve cosmesis. Most of the available treatment modalities traumatize the lesions and have to be undertaken in the hospital, therefore evoking panic in children. In the quest for an alternative therapy, this study comparing 10% potassium hydroxide (KOH) solution and 5% imiquimod cream was taken up.

Aims and Objectives:

To compare the efficacy and tolerability of 10% KOH and 5% imiquimod in the treatment of MC.

Materials and Methods:

This comparative study was conducted over a period of 18 months from October 2011 to March 2013, 40 patients between the age group of 1-18 years with clinically diagnosed MC were divided into two groups (lottery method), 20 patients were treated with 5% imiquimod cream (Group A) and the other 20 were treated with 10% KOH solution (Group B). Patients were followed up on the 4^th, 8^th and 12^th week of treatment.

Results:

At the end of 12 weeks, out of 20 patients who received 10% KOH, 17 patients showed complete disappearance, whereas out of 20 patients who received 5% imiquimod, only 10 patients showed total clearance of the lesions. Adverse events were more frequent with 10% KOH, pigmentary disturbances being the most common.

Conclusion:

With only minor adverse effects, 10% KOH is an inexpensive and efficient modality for the treatment of MC in the pediatric age group. Although 5% imiquimod was effective in clearing the lesions with minimal adverse effects, the longer duration required for its efficacy may deter its wider use.