Ethnic identity predicts experimental pain sensitivity in African Americans and Hispanics

In Vivo praying and catastrophizing mediate the race differences in experimental pain sensitivity

Black individuals have a lower tolerance for experimental pain than white individuals. Black and white individuals also differ in their use of pain coping strategies, which may explain the race differences in pain sensitivity. We examined the extent to which situation-specific pain coping mediated black-white differences in pain sensitivity. We hypothesized that 1) black participants would demonstrate lower pain tolerance than white participants, 2) black participants would use different pain coping strategies than white participants, and 3) the differential use of these strategies would mediate the relationship between race and pain tolerance. Healthy college undergraduates (N = 190) participated in a cold pressor task and then completed the Coping Strategies Questionnaire-Revised to assess their situation-specific pain coping. Compared with white participants, black participants demonstrated lower pain tolerance, engaged in more situation-specific catastrophizing and praying, and ignored pain less frequently. Catastrophizing and praying were inversely related to pain tolerance and were significant mediators of the relationship between race and pain tolerance. The indirect effect of praying was stronger than that of catastrophizing. Race differences in pain sensitivity may be due, in part, to differences in the use of catastrophizing and praying as coping strategies. These results may help guide treatments addressing maladaptive pain coping.

PERSPECTIVE

This study suggests that race differences in pain sensitivity may be due, in part, to the differential use of catastrophizing and praying strategies. Psychosocial treatments for pain should encourage patients to take an active role in their pain management.

On the importance of being vocal: saying "ow" improves pain tolerance

Vocalizing is a ubiquitous pain behavior. The present study investigated whether it helps alleviate pain and sought to discern potential underlying mechanisms. Participants were asked to immerse one hand in painfully cold water. On separate trials, they said "ow," heard a recording of them saying "ow," heard a recording of another person saying "ow," pressed a button, or sat passively. Compared to sitting passively, saying "ow" increased the duration of hand immersion. Although on average, participants predicted this effect, their expectations were uncorrelated with pain tolerance. Like vocalizing, button pressing increased the duration of hand immersion, and this increase was positively correlated with the vocalizing effect. Hearing one's own or another person's "ow" was not analgesic. Together, these results provide first evidence that vocalizing helps individuals cope with pain. Moreover, they suggest that motor more than other processes contribute to this effect.

PERSPECTIVE

Participants immersed their hand in painfully cold water longer when saying "ow" than when doing nothing. Whereas button pressing had a similar effect, hearing one's own or another person's "ow" did not. Thus, vocalizing in pain is not only communicative. Like other behaviors, it helps cope with pain.

Evaluation of measurement equivalence of the Family Satisfaction with the End-of-Life Care in an ethnically diverse cohort: tests of differential item functioning

BACKGROUND

The Family Satisfaction with End-of-Life Care is an internationally used measure of satisfaction with cancer care. However, the Family Satisfaction with End-of-Life Care has not been studied for equivalence of item endorsement across different socio-demographic groups using differential item functioning.

AIMS

The aims of this secondary data analysis were (1) to examine potential differential item functioning in the family satisfaction item set with respect to type of caregiver, race, and patient age, gender, and education and (2) to provide parameters and documentation of differential item functioning for an item bank.

DESIGN

A mixed qualitative and quantitative analysis was conducted. A priori hypotheses regarding potential group differences in item response were established. Item response theory and Wald tests were used for the analyses of differential item functioning, accompanied by magnitude and impact measures.

RESULTS

Very little significant differential item functioning was observed for patient's age and gender. For race, 13 items showed differential item functioning after multiple comparison adjustment, 10 with non-uniform differential item functioning. No items evidenced differential item functioning of high magnitude, and the impact was negligible. For education, 5 items evidenced uniform differential item functioning after adjustment, none of high magnitude. Differential item functioning impact was trivial. One item evidenced differential item functioning for the caregiver relationship variable.

CONCLUSION

Differential item functioning was observed primarily for race and education. No differential item functioning of high magnitude was observed for any item, and the overall impact of differential item functioning was negligible. One item, satisfaction with "the patient's pain relief," might be singled out for further study, given that this item was both hypothesized and observed to show differential item functioning for race and education.

Correlations between social-emotional feelings and anterior insula activity are independent from visceral states but influenced by culture

The anterior insula (AI) maps visceral states and is active during emotional experiences, a functional confluence that is central to neurobiological accounts of feelings. Yet, it is unclear how AI activity correlates with feelings during social emotions, and whether this correlation may be influenced by culture, as studies correlating real-time AI activity with visceral states and feelings have focused on Western subjects feeling physical pain or basic disgust. Given psychological evidence that social-emotional feelings are cognitively constructed within cultural frames, we asked Chinese and American participants to report their feeling strength to admiration and compassion-inducing narratives during fMRI with simultaneous electrocardiogram recording. Trial-by-trial, cardiac arousal and feeling strength correlated with ventral and dorsal AI activity bilaterally but predicted different variance, suggesting that interoception and social-emotional feeling construction are concurrent but dissociable AI functions. Further, although the variance that correlated with cardiac arousal did not show cultural effects, the variance that correlated with feelings did. Feeling strength was especially associated with ventral AI activity (the autonomic modulatory sector) in the Chinese group but with dorsal AI activity (the visceral-somatosensory/cognitive sector) in an American group not of Asian descent. This cultural group difference held after controlling for posterior insula (PI) activity and was replicated. A bi-cultural East-Asian American group showed intermediate results. The findings help elucidate how the AI supports feelings and suggest that previous reports that dorsal AI activation reflects feeling strength are culture related. More broadly, the results suggest that the brain's ability to construct conscious experiences of social emotion is less closely tied to visceral processes than neurobiological models predict and at least partly open to cultural influence and learning.

Prevalence of suicidality among Hispanic and African American veterans following surgery

OBJECTIVES

We evaluated factors associated with suicidal behavior and ideation (SBI) during 3 years of follow-up among 89,995 Veterans Health Administration (VHA) patients who underwent major surgery from October 2005 to September 2006.

METHODS

We analyzed administrative data using Cox proportional hazards models. SBI was ascertained by International Classification of Disease, 9th Revision codes.

RESULTS

African Americans (18% of sample; 16,252) were at an increased risk for SBI (hazard ratio [HR] = 1.21; 95% confidence interval [CI]  = 1.10, 1.32), whereas Hispanics were not (HR = 1.10; 95% CI = 0.95, 1.28). Other risk factors included schizophrenia, bipolar disorder, depression, posttraumatic stress disorder, pain disorders, postoperative new-onset depression, and postoperative complications; female gender and married status were protective against SBI.

CONCLUSIONS

The postoperative period might be a time of heightened risk for SBI among minority patients in the VHA. Tailored monitoring and postoperative management by minority status might be required to achieve care equity.

Cross-sectional study on differences in pain perception and behavioral distress during venipuncture between italian and chinese children

Venipuncture is perhaps the scariest aspect of hospitalization for children as it causes pain and high levels of behavioral distress. Pain is a complex experience which is also influenced by social factors such as cultural attitudes, beliefs and traditions. Studies focusing on ethnic/cultural differences in pain perception and behavioral distress show controversial results, in particular with regards to children. The aim of this paper is to evaluate differences in pain perception and behavioral manifestations between Italian and Chinese children undergoing a venipuncture, through a cross-sectional study. Behavioral distress and self-reported pain were measured in Chinese and Italian outpatient children during a standardized blood-drawing procedure, using the Observational Scale of Behavioral Distress (OSBD) and pain scales. We observed 332 children: 93 Chinese and 239 Italian. Chinese children scored higher than Italians on pain scales - mean scores 5.3 (95%CI 4.78-5.81) vs. 3.2 (95%CI 2.86-3.53) - but lower mean OSBD scores - mean 4.1 (95%CI 3.04-5.15) vs. 8.1 (95%CI 7.06-9.14). Our data suggest that Chinese children experience higher levels of pain than their Italian peers, although they show more self-control in their behavioral reaction to pain when experiencing venipuncture.

The effect of repeated intramuscular alfentanil injections on experimental pain and abuse liability indices in healthy males

OBJECTIVE

Opioid-induced hyperalgesia (OIH), increased sensitivity to noxious stimuli after repeated opioid exposures, has been demonstrated in preclinical studies. However, there is no accepted, prospective model of OIH after repeated opioid exposures currently available in humans. This study assessed a potential prospective OIH model.

METHODS

Double-blind intramuscular injections of a short-acting opioid (alfentanil 15 mcg/kg; N=8) were compared to active placebo (diphenhydramine 25 mg; N=3) on cold and pressure pain testing and standard abuse liability measures in eight 10-hour sessions (1 injection/session) over 4 to 5 weeks in healthy, pain-free males. Decreases from session baseline pain threshold (PThr) and tolerance (PTol) were calculated to represent hyperalgesia, and were assessed both within and across sessions.

RESULTS

Mean decreases in cold PTol were seen in the alfentanil group at 180 minutes (-3.8 s, ±26.5) and 480 minutes (-1.63 s, ±31.5) after drug administration. There was a trend for differences between conditions on cold PThr hyperalgesia but not for pressure PThr. Alfentanil participants had greater mean ratings on Liking and High visual analog scales at peak effects (30 min), but these scores did not change across sessions.

DISCUSSION

Repeated alfentanil exposures over 4 to 5 weeks resulted in within session decreases in cold pain tolerance from baseline but these differences were not substantially different from diphenhydramine controls. The results did not support the phenomenon of OIH in this model, although definitive conclusions regarding the existence of OIH in humans likely requires a larger sample size or an alternative model.

Longitudinal interactions of pain and posttraumatic stress disorder symptoms in U.S. Military service members following blast exposure

Military personnel returning from conflicts in Iraq and Afghanistan often endorse pain and posttraumatic stress disorder (PTSD) symptoms, either separately or concurrently. Associations between pain and PTSD symptoms may be further complicated by blast exposure from explosive munitions. Although many studies have reported on the prevalence and disability associated with polytraumatic injuries following combat, less is known about symptom maintenance over time. Accordingly, this study examined longitudinal interactive models of co-occurring pain and PTSD symptoms in a sample of 209 military personnel (mean age = 27.4 years, standard deviation = 7.6) who experienced combat-related blast exposure. Autoregressive cross-lagged analysis examined longitudinal associations between self-reported pain and PTSD symptoms over a 1-year period. The best-fitting covariate model indicated that pain and PTSD were significantly associated with one another across all assessment periods, χ² (3) = 3.66, P = .30, Tucker-Lewis index = .98, comparative fit index = 1.00, root mean squared error of approximation = .03. PTSD symptoms had a particularly strong influence on subsequent pain symptoms. The relationship between pain and PTSD symptoms is related to older age, race, and traumatic brain injury characteristics. Results further the understanding of complex injuries among military personnel and highlight the need for comprehensive assessment and rehabilitation efforts addressing the interdependence of pain and co-occurring mental health conditions.

PERSPECTIVE

This longitudinal study demonstrates that pain and PTSD symptoms strongly influence one another and interact across time. These findings have the potential to inform the integrative assessment and treatment of military personnel with polytrauma injuries and who are at risk for persistent deployment-related disorders.

Hispanic Inpatient Pain Intensity

Hispanic adults experience significant pain, but little is known about their pain during hospitalization. The purpose of this research was to describe Hispanic inpatients' pain intensity and compare their pain intensity with that of non-Hispanic patients. A post hoc descriptive design was used to examine 1,466 Hispanic inpatients' medical records (63.2% English speakers) and 12,977 non-Hispanic inpatients' medical records from one hospital for 2012. Mean documented pain intensity was mild for both Hispanic and non-Hispanic inpatients. Pain intensity was greater for English-speaking Hispanic patients than Spanish speakers. The odds of being documented with moderate or greater pain intensity decreased 30% for Spanish-speaking patients. Greater pain intensity documented for English-speaking Hispanic inpatients suggests underreporting of pain intensity by Spanish-speaking patients. Practitioners should use interpreter services when assessing and treating pain with patients who speak languages different from the practitioners' language(s).

Dose requirements of remifentanil for intubation in nonparalyzed Chinese children

BACKGROUND

The objective of this study was to determine ED50 and ED95 of remifentanil for intubation combined with propofol in nonparalyzed Chinese children.

METHODS

Forty-seven American Society of Anesthesiologists Class I children aged 4-11 years weighing 14-33.5 kg underwent general anesthesia with 2.5 mg·kg(-1) of intravenous propofol followed by remifentanil in Wenzhou, China. The initial dose of remifentanil was 2.5 μg·kg(-1) injected over 60 s. Intubation was attempted 30 s after the completion of remifentanil injection. Level of difficulty to intubate was graded on a scoring system. If the initial intubation condition was deemed satisfactory, subsequent remifentanil doses were decreased by 0.25 μg·kg(-1). If the intubating condition was deemed unsatisfactory, subsequent remifentanil doses were increased by 0.25 μg·kg(-1). Mean arterial pressure, heart rate, and pulse oximetry were documented before and after induction, immediately after intubation, and 1 min after intubation.

RESULTS

The ED50 of remifentanil used to render a satisfactory intubating condition used in combination with 2.5 mg·kg(-1) of propofol in nonparalyzed Chinese children was 2.30 μg·kg(-1) (95% confidence interval: 2.28-2.31 μg·kg(-1)), and the ED95 is 2.75 μg·kg(-1) (95% confidence interval: 2.59-3.35 μg·kg(-1)). These doses were lower than previously reported.

CONCLUSION

When used in combination with 2.5 mg·kg(-1) of intravenous propofol, ED50 and ED95 of remifentanil for adequate intubation in nonparalyzed children were lower than previously reported, at 2.30 and 2.75 μg·kg(-1), respectively.

Demographic differences in health preferences in the United States

BACKGROUND

The United States has a culturally and demographically diverse populace, and the aim of this study was to examine differences in health preferences by sex, age, ethnicity, and race.

METHODS

We assessed preferences for health outcomes defined by the PROMIS-29 survey in a sample of the US population. On the basis of the survey's 540 paired-comparisons trading off lifespan and 7 domains of health-related quality of life (HRQoL), we compared the choices between men and women, adults age 18-54 years and 55 years and older, Hispanics and non-Hispanics, and non-Hispanic blacks and whites. For each subgroup, we estimated the value of 122 HRQoL outcomes on a quality-adjusted life year scale and tested for subgroup differences.

RESULTS

Compared with men, women preferred reduced lifespan over losses in HRQoL, particularly for depression. Compared with the younger adults, older adults preferred reduced lifespan over the symptoms of depression, anxiety, and fatigue. Compared with non-Hispanic whites, Hispanics preferred reduced lifespan over depression and sleep disturbance, but held similar values on losses in physical functioning. Among non-Hispanics, blacks preferred reduced lifespan over losses in ability to climb stairs and to fall asleep compared with whites, but held similar values on mental health outcomes.

CONCLUSIONS

With the growing emphasis on patient-centeredness and culturally sensitive treatment, it is important to recognize the diversity in values placed on potential losses in HRQoL, particularly mental health outcomes. Demographic differences in preferences may influence comparative or cost effectiveness of treatments as perceived by one or another subgroup.

Pharmacokinetic-pharmacodynamic modelling of the analgesic and antihyperalgesic effects of morphine after intravenous infusion in human volunteers

Using a modelling approach, this study aimed to (i) examine whether the pharmacodynamics of the analgesic and antihyperalgesic effects of morphine differ; (ii) investigate the influence of demographic, pain sensitivity and genetic (OPRM1) variables on between-subject variability of morphine pharmacokinetics and pharmacodynamics in human experimental pain models. The study was a randomized, double-blind, 5-arm, cross-over, placebo-controlled study. The psychophysical cutaneous pain tests, electrical pain tolerance (EPTo) and secondary hyperalgesia areas (2HA) were studied in 28 healthy individuals (15 males). The subjects were chosen based on a previous trial where 100 subjects rated (VAS) their pain during a heat injury (47°C, 7 min., 12.5 cm(2) ). The 33% lowest- and highest pain-sensitive subjects were offered participation in the present study. A two-compartment linear model with allometric scaling for weight provided the best description of the plasma concentration-time profile of morphine. Changes in the EPTo and 2HA responses with time during the placebo treatment were best described by a linear model and a quadratic model, respectively. The model discrimination process showed clear evidence for adding between-occasion variability (BOV) on baseline and the placebo slope for EPTo and 2HA, respectively. The sensitivity covariate was significant on baseline EPTo values and genetics as a covariate on the placebo slope for 2HA. The analgesic and antihyperalgesic effects of morphine were pharmacologically distinct as the models had different effect site equilibration half-lives and different covariate effects. Morphine had negligible effect on 2HA, but significant effect on EPTo.

OCT1 genetic variants influence the pharmacokinetics of morphine in children

AIM

Large interindividual variability in morphine disposition could contribute to unpredictable variability in morphine analgesia and adverse events. Caucasian children have more adverse effects and slower morphine clearance than African-American children. To study variations in intravenous morphine pharmacokinetics in children, we examined the influence of genetic polymorphisms in OCT1.

METHODS

In 146 children undergoing adenotonsillectomy, 146 concentration-time profiles (2-4 measurements per patient) were available. Population pharmacokinetic analysis characterized the profiles in NONMEM(®) and tested OCT1 variants as covariates.

RESULTS

Allometrically scaled post hoc Bayesian morphine clearance in homozygotes of loss-of-function OCT1 variants (n = 9, OCT1*2-*5/*2-*5) was significantly lower (20%) than in wild-type (n = 85, OCT1*1/*1) and heterozygotes (n = 52, OCT1*1/*2-*5; p < 0.05).

CONCLUSION

Besides bodyweight, OCT1 genotypes play a significant role in intravenous morphine pharmacokinetics. Relatively high allelic frequencies of defective OCT1 variants among Caucasians may explain their lower morphine clearance and possibly higher frequencies of adverse events compared with African-American children. Original submitted 21 December 2012; Revision submitted 7 May 2013.

Pharmacogenomics of opioids and perioperative pain management

Inadequate pain relief and adverse effects from analgesics remain common in children and adults during the perioperative period. Opioids are the most commonly used analgesics in children and adults to treat perioperative pain. Narrow therapeutic index and a large interpatient variability in response to opioids are clinically significant, with inadequate pain relief at one end of the spectrum and serious side effects, such as respiratory depression and excessive sedation due to relative overdosing, at the other end. Personalizing analgesia during the perioperative period attempts to maximize pain relief while minimizing adverse events from therapy. While various factors influence response to treatment among surgical patients, age, sex, race and pharmacogenetic differences appear to play major roles in predicting outcome. Genetic factors include a subset of genes that modulate the proteins involved in pain perception, pain pathway, analgesic metabolism (pharmacokinetics), transport and receptor signaling (pharmacodynamics). While results from adult genetic studies can provide direction for pediatric studies, they have limited direct applicability, as children's genetic predispositions to analgesic response may be influenced by developmental and behavioral components, altered sensitivity to analgesics and variation in gene-expression patterns. We have reviewed the available evidence on improving and personalizing pain management with opioids and the significance of individualizing analgesia, in order to maximize analgesic effect with minimal adverse effects with opioids. While the early evidence on individual genotype associations with pain, analgesia and opioid adverse outcome are promising, the large amount of conflicting data in the literature suggests that there is a need for larger and more robust studies with appropriate population stratification and consideration of nongenetic and other genetic risk factors. Although the clinical evidence and the prospect of being able to provide point-of-care genotyping to enable clinicians to deliver personalized analgesia for individual patients is still not available, positioning our research to identify all possible major genetic and nongenetic risk factors of an individual patient, advancing less expensive point-of-care genotyping technology and developing easy-to-use personalized clinical decision algorithms will help us to improve current clinical and economic outcomes associated with pain and opioid pain management.

Experimental pain phenotype profiles in a racially and ethnically diverse sample of healthy adults

OBJECTIVE

To examine patterns of interindividual variability in experimental pain responses emerging from multiple experimental pain measures in a racially/ethnically diverse sample of healthy adults and to examine the association between the derived phenotype profiles with demographic, psychological, and health-related measures.

METHODS

Two hundred and ninety-one participants underwent heat, cold, pressure, and ischemic pain assessments, and completed several psychological and health-related assessments. The experimental pain measures were subjected to a principal component analysis and factor scores were used to compute Pain Sensitivity Index scores. The scores were subsequently submitted to a cluster analysis to identify patterns of pain sensitivity across experimental pain modalities.

RESULTS

The sample was equally composed of non-Hispanic whites, African Americans, and Hispanic whites. Sensitivity scores were computed for heat pain, pressure pain, cold pain, ischemic pain, and temporal summation of heat pain. Five distinct clusters were characterized by high heat pain sensitivity, low ischemic pain sensitivity, low cold pain sensitivity, low pressure pain sensitivity, and high temporal summation. Cluster membership was significantly different by sex as well as somatic reactivity and catastrophizing, although cluster differences were most pronounced between the heat pain-sensitive individuals vs the cold pain-insensitive individuals.

CONCLUSIONS

Our findings highlight the importance of phenotyping individuals to account for interindividual differences in pain responses. Our findings also replicate previously reported pain phenotypes, which are not solely related to demographic, psychosocial, or health-related factors in our healthy participants. Future studies designed to elucidate the biological underpinnings of pain sensitivity profiles would be of substantial value.

Multiethnic differences in responses to laboratory pain stimuli among children

OBJECTIVE

A growing body of literature suggests ethnic differences in experimental pain. However, these studies largely focus on adults and the comparison between Caucasians and African Americans. The primary aim of this study is to determine ethnic differences in laboratory-induced pain in a multiethnic child sample.

METHOD

Participants were 214 healthy children (mean age = 12.7, SD = 3.0 years). Ninety-eight Caucasian, 58 Hispanic, 34 African American, and 24 Asian children were exposed to four trials of pressure and radiant heat pain stimuli. Pain responses were assessed with self-report measures (i.e., pain intensity and unpleasantness) and behavioral observation (i.e., pain tolerance).

RESULTS

Asians demonstrated more pain sensitivity than Caucasians, who evidenced more pain sensitivity than African Americans and Hispanics. The results hold even after controlling for age, sex, SES, and experimenter's ethnicity. Asians also showed higher anticipatory anxiety compared with other ethnic groups. Anticipatory anxiety accounted for some ethnic differences in pain between Asians, Hispanics, and African Americans.

CONCLUSIONS

By examining response to laboratory pain stimuli in children representing multiple ethnicities, an understudied sample, the study reveals unique findings compared to the existing literature. These findings have implications for clinicians who manage acute pain in children from diverse ethnic backgrounds. Future investigations should examine mechanisms that account for ethnic differences in pain during various developmental stages.

Surgically induced neuropathic pain: understanding the perioperative process

Nerve damage takes place during surgery. As a consequence, significant numbers (10%-40%) of patients experience chronic neuropathic pain termed surgically induced neuropathic pain (SNPP). The initiating surgery and nerve damage set off a cascade of events that includes both pain and an inflammatory response, resulting in "peripheral and central sensitization," with the latter resulting from repeated barrages of neural activity from nociceptors. In affected patients, these initial events produce chemical, structural, and functional changes in the peripheral and central nervous systems (CNS). The maladaptive changes in damaged nerves lead to peripheral manifestations of the neuropathic state-allodynia, sensory loss, shooting pains, etc, that can manifest long after the effects of the surgical injury have resolved. The CNS manifestations that occur are termed "centralization of pain" and affect sensory, emotional, and other (eg, cognitive) systems as well as contributing to some of the manifestations of the chronic pain syndrome (eg, depression). Currently there are no objective measures of nociception and pain in the perioperative period. As such, intermittent or continuous pain may take place during and after surgery. New technologies including direct measures of specific brain function of nociception and new insights into preoperative evaluation of patients including genetic predisposition, appear to provide initial opportunities for decreasing the burden of SNPP, until treatments with high efficacy and low adverse effects that either prevent or treat pain are discovered.

Itch pathophysiology may differ among ethnic groups

The prevalence of itch is higher in individuals with darker skin types. In this paper, we review the systems involved in the physiology of itch and how they may differ across the races. Current data point out that the differences may be explained by barrier function, mast cell physiology, and itch receptor polymorphisms.

Gender role expectations of pain mediate sex differences in cold pain responses in healthy Libyans

Previous studies found a relationship between response to experimentally-induced pain and scores for the gender role expectations of pain (GREP) questionnaire. Findings were similar in individuals from America, Portugal and Israel suggesting that gender role expectations may be universal. The aim of this study was to translate and validate Arabic GREP using Factor Analysis and to investigate if sex differences to cold-pressor pain in healthy Libyan men and women are mediated through stereotypical social constructs of gender role expectations and/or pain-related anxiety. One hundred fourteen university students (58 women) underwent two cycles of cold pressor pain test to measure pain threshold, tolerance, intensity, and unpleasantness. Participants also completed the Arabic GREP questionnaire and the Pain Anxiety Symptom Scale-Short form (PASS-20). It was found that Libyan men had higher pain thresholds and tolerances than women (mean difference, 95% CI: threshold = 4.69 (s), -0.72 to 10.1, p = 0.005; tolerance = 13.46 (s), 0.5-26.4, p = 0.018). There were significant differences between sexes in 6 out of 12 GREP items (p < 0.004 after Bonferonni adjustment). The results of mediational analysis showed that GREP factors were the mediators of the effects of sex on pain threshold (z = -2.452, p = 0.014 for Self Sensitivity); (z = -2.563, p = 0.01, for Self Endurance) and on pain tolerance (z = -2.538, p = 0.01 for Self Endurance). In conclusion, sex differences in response to pain were mediated by gender role expectations of pain but not pain-related anxiety.

The role of mental distraction on the pain response in healthy young Indian adults

BACKGROUND AND OBJECTIVES

The pain sensitivity of a person depends on the type of pain, his/her genetics, racial and cultural factors. Its dependence on the gender is debatable. The significance of the psychological or the behavioural intervention in pain management is gaining importance, along with a reduction in the doses of the analgesics. We wished to investigate (a) whether Indian subjects showed a pain response which was similar to that which was reported for American subjects, (b) whether sex-related differences in the pain response were present in the Indian population, and (c) which method of mental distraction (from a choice of the presence of a male/female attendant, preferred music, and solving simple arithmetic problems) was best suited for the Indian subjects.

METHODS

The cold pressor task was performed on a group of 80 subjects (38 females who were in the proliferative or the secretory phase of the menstrual cycle) under the conditions which have been mentioned above, as well as in the absence of mental distractants.

RESULTS

The female subjects endured pain for a longer duration while they listened to the music of their choice; the male subjects endured pain longer while they were in conversation with the female attendants.

INTERPRETATION AND CONCLUSIONS

A comparison with the reported data showed the Indian males to be more pain-sensitive than the American males. Sex related differences in the pain sensitivity were absent in the Northern Indian subjects. Preferred music was the most effective mental distractant for females, while a conversation with the female attendants was the most effective distractant for the male subjects.

Vitamin D, race, and experimental pain sensitivity in older adults with knee osteoarthritis

OBJECTIVE

Low circulating serum levels of 25-hydroxyvitamin D (referred to hereafter as vitamin D) have been correlated with many health conditions, including chronic pain. Recent clinical practice guidelines define vitamin D levels <20 ng/ml as deficient and levels of 21-29 ng/ml as insufficient. Vitamin D insufficiency, including the most severe levels of deficiency, is more prevalent in black Americans. Ethnic and race group differences have been reported in both clinical and experimental pain, with black Americans reporting increased pain. The purpose of this study was to examine whether variations in vitamin D levels contribute to race differences in knee osteoarthritis pain.

METHODS

The sample consisted of 94 participants (74% women), including 45 blacks and 49 whites with symptomatic knee osteoarthritis. Their average age was 55.8 years (range 45-71 years). Participants completed a questionnaire on knee osteoarthritis symptoms and underwent quantitative sensory testing, including measures of sensitivity to heat-induced and mechanically induced pain.

RESULTS

Blacks had significantly lower levels of vitamin D compared to whites, demonstrated greater clinical pain, and showed greater sensitivity to heat-induced and mechanically induced pain. Low levels of vitamin D predicted increased experimental pain sensitivity, but did not predict self-reported clinical pain. Group differences in vitamin D levels significantly predicted group differences in heat pain and pressure pain thresholds at the index knee and ipsilateral forearm.

CONCLUSION

These data demonstrate that race differences in experimental pain are mediated by differences in the vitamin D level. Vitamin D deficiency may be a risk factor for increased knee osteoarthritis pain in black Americans.

Ethnicity and reported pain scores among children with long-bone fractures requiring emergency care

OBJECTIVES

Previous studies have shown that regular pain measurement improves pain management. As the diversity of patients seeking emergency care continues to grow, a better understanding of the potential differences in pain perception and analgesic needs among various cultural groups will be required. The purpose of this study was to describe the differences in pain scores reported among ethnic groups treated for a long-bone fracture.

METHODS

A retrospective review of patients with a long-bone fracture treated in an urban pediatric emergency department during a 12-month period was performed. Pain scores were assessed using previously validated pain scales.

RESULTS

Eight hundred eighty patients met our inclusion criteria. Wrist fracture was the most common type of fracture in our study. There were significant differences noted in reported pain scores. Patients identified as Hmong had the highest pain scores, and patients identified as Somali had the lowest pain scores reported. Patients with wrist fractures had the highest average pain score when compared with other types of fractures. Children with fractures requiring reduction in the emergency department had higher pain scores than those who had a fracture that did not require reduction.

CONCLUSIONS

To our knowledge, this is the first study to investigate the relationships between ethnicity and pain scores reported in children treated emergently for a long-bone fracture.

Effects of ethnicity and gender role expectations of pain on experimental pain: a cross-cultural study

BACKGROUND

Gender role expectations of pain (GREP) have been shown to mediate sex differences in experimental pain. Few studies have investigated the role of ethnicity in shaping GREP. The aim of this study was to examine interactions between ethnicity and GREP on experimentally induced pressure and ischaemic pain in Libyan and white British students in their respective countries.

METHODS

Libyan (n = 124) and white British (n = 51) students completed a GREP questionnaire and their response to experimental pain was measured. Blunt pressure pain threshold (PPT) was measured over the 1st interosseous muscle using algometry. Pain intensity and pain unpleasantness (100 mm visual analogue scale) were measured at 1-min intervals during a submaximal effort tourniquet test on the forearm.

RESULTS

Multivariate analysis of variance detected significant effects for Sex and Ethnicity on pain measurements. Men had higher PPTs than women (p < 0.001). Libyans had higher PPTs than white British participants (p < 0.001). There were significant effects for Sex and Ethnicity for pain intensity ratings (p < 0.01) but no significant differences between the sexes in pain unpleasantness (p > 0.05). Libyan participants had higher pain intensity (p < 0.01) and pain unpleasantness (p < 0.05) ratings compared with white British participants. There were effects for Sex and Ethnicity for all GREP dimensions. Libyan participants exhibited stronger stereotypical views in GREP than white British participants (p < 0.001).

CONCLUSIONS

GREP was the mediator of sex but not ethnic differences in pain report, suggesting that gender stereotypical attitudes to pain account for differences in pain expression between men and women.

Ethnic differences in physical pain sensitivity: role of acculturation

Although research suggests that Asian Americans are more reactive to physical pain than European Americans, some evidence suggests that the observed differences in ethnicity may actually reflect Asian Americans' differing levels of acculturation. Two studies were conducted to test this hypothesis. In Study 1, first- and second-generation Asian Americans and European Americans took part in a cold pressor task. Evidence of heightened pain responses was found only among first-generation Asian Americans. Study 2 further controlled for ethnicity and replicated this pattern in finding heightened pain reactions among mainland Chinese students in Hong Kong relative to Hong Kong Chinese students. These findings suggest a role for acculturation in accounting for ethnic differences in physical pain sensitivity.

Prediction of pain sensitivity in healthy volunteers

PURPOSE

The primary objective of the present study was to evaluate predictive parameters of the acute pain score during induction of an inflammatory heat injury.

PATIENTS AND METHODS

Healthy volunteers (50 females/50 males) were included in the study. The predictive potential of gender, anthropometric (body surface area, body mass index), psychological (anxiety, depression, vulnerability), and psychophysical (quantitative sensory testing, conditioned pain modulation) variables in estimating the pain response to a validated heat injury (47°C, 7 minutes, area 12.5 cm(2)) were investigated. All assessments were made in duplicate sessions separated by 21 days (median).

RESULTS

There were three main findings in this study. First, a predictive model of pain sensitivity during the heat injury, including both genders and using multiple regression technique, could account for 28% of the variance (P < 0.0001), but gender-related differences in the final model could not be demonstrated. Second, the results confirmed significant gender-related differences in perception of electrical, pressure, and cold pressor stimuli (P < 0.002). Third, positive correlations between anthropometric data and pain perception during electrical and pressure stimuli were demonstrated (P < 0.001 and P < 0.005, respectively).

CONCLUSION

The study demonstrated predictability of acute pain sensitivity, and although gender-related differences in pain perception were demonstrated, no gender-related differences in pain sensitivity could be shown. Interestingly, positive correlations between anthropometric data and pain perception were shown for the first time.

Pain sensitivity risk factors for chronic TMD: descriptive data and empirically identified domains from the OPPERA case control study

Many studies report that people with temporomandibular disorders (TMD) are more sensitive to experimental pain stimuli than TMD-free controls. Such differences in sensitivity are observed in remote body sites as well as in the orofacial region, suggesting a generalized upregulation of nociceptive processing in TMD cases. This large case-control study of 185 adults with TMD and 1,633 TMD-free controls measured sensitivity to painful pressure, mechanical cutaneous, and heat stimuli, using multiple testing protocols. Based on an unprecedented 36 experimental pain measures, 28 showed statistically significantly greater pain sensitivity in TMD cases than controls. The largest effects were seen for pressure pain thresholds at multiple body sites and cutaneous mechanical pain threshold. The other mechanical cutaneous pain measures and many of the heat pain measures showed significant differences, but with lesser effect sizes. Principal component analysis (PCA) of the pain measures derived from 1,633 controls identified 5 components labeled: 1) heat pain ratings; 2) heat pain aftersensations and tolerance; 3) mechanical cutaneous pain sensitivity; 4) pressure pain thresholds; and 5) heat pain temporal summation. These results demonstrate that compared to TMD-free controls, chronic TMD cases are more sensitive to many experimental noxious stimuli at extracranial body sites, and provide for the first time the ability to directly compare the case-control effect sizes of a wide range of pain sensitivity measures.

PERSPECTIVE

This article describes experimental pain sensitivity differences between a large sample of people with chronic TMD and non-TMD controls, using multiple stimulus modalities and measures. Variability in the magnitude and consistency of case-control differences highlight the need to consider multiple testing measures to adequately assess pain processing alterations in chronic pain conditions.

Potential psychosocial risk factors for chronic TMD: descriptive data and empirically identified domains from the OPPERA case-control study

Case-control studies have consistently associated psychosocial factors with chronic pain in general, and with temporomandibular disorders (TMD) specifically. Moreover, a handful of prospective studies suggest that preexisting psychosocial characteristics represent risk factors for new onset TMD. The current study presents psychosocial findings from the baseline case-control study of the Orofacial Pain Prospective Evaluation and Risk Assessment (OPPERA) cooperative agreement. For this study, 1,633 TMD-free controls and 185 TMD cases completed a battery of psychosocial instruments assessing general psychosocial adjustment and personality, affective distress, psychosocial stress, somatic awareness, and pain coping and catastrophizing. In bivariate and demographically adjusted analyses, odds of TMD were associated with higher levels of psychosocial symptoms, affective distress, somatic awareness, and pain catastrophizing. Among controls, significant gender and ethnic group differences in psychosocial measures were observed, consistent with previous findings. Principal component analysis was undertaken to identify latent constructs revealing 4 components: stress and negative affectivity, global psychosocial symptoms, passive pain coping, and active pain coping. These findings provide further evidence of associations between psychosocial factors and TMD. Future prospective analyses in the OPPERA cohort will determine if the premorbid presence of these psychosocial factors predicts increased risk for developing new onset TMD.

PERSPECTIVE

This article reports baseline psychosocial findings from the OPPERA Study, a large prospective cohort study designed to discover causal determinants of TMD pain. Findings indicate significant differences between TMD cases and TMD-free controls across multiple psychosocial constructs, and future analyses will determine whether these psychosocial factors increase risk for new onset TMD.

Pain catastrophizing: an updated review

Pain catastrophizing has been described for more than half a century which adversely affects the pain coping behavior and overall prognosis in susceptible individuals when challenged by painful conditions. It is a distinct phenomenon which is characterized by feelings of helplessness, active rumination and excessive magnification of cognitions and feelings toward the painful situation. Susceptible subjects may have certain demographic or psychological predisposition. Various models of pain catastrophizing have been proposed which include attention-bias, schema-activation, communal-coping and appraisal models. Nevertheless, consensus is still lacking as to the true nature and mechanisms for pain catastrophizing. Recent advances in population genomics and noninvasive neuroimaging have helped elucidate the known determinants and neurophysiological correlates behind this potentially disabling behavior.

Geographic differences in perioperative opioid administration in children

OBJECTIVES

To investigate whether geographic differences exist in perioperative opioid administration to children.

AIM

  To investigate whether perioperative fentanyl use for cleft lip and palate surgery varies between children of three different geographic regions.

BACKGROUND

Differences have been found in perioperative opioid administration to children of differing ethnicity in the USA. Whether similar differences exist in perioperative opioid administration to children residing in different geographic regions is unknown.

METHODS/MATERIALS

We retrospectively reviewed the medical records of ASA I children who underwent surgery under standardized general anesthesia between January 2010 and April 2011 during SMILE Network International mission trips to Africa, India and Central and South America. Perioperative administration of fentanyl was compared between these three locations.

RESULTS

We analyzed data from 79 children who underwent surgery in Africa, 76 in India and 153 in Central and South America. Children in Central and South America were given <50% of the intraoperative amount of fentanyl (2.0 ± 1.2 mcg·kg(-1) ) administered to children in Africa (4.1 ± 2.4 mcg·kg(-1) ; P < 0.001) and children in India (4.3 ± 2.2 mcg·kg(-1) ; P < 0.001). Postoperatively, fentanyl was administered in equivalent doses to all groups.

CONCLUSIONS

Children in Central and South America received less opioid intraoperatively than African and Indian children, under standardized anesthesia for cleft surgeries. Further research is necessary to elucidate the mechanisms underlying these group differences.

Ethnicity interacts with the OPRM1 gene in experimental pain sensitivity

Robust interindividual variation in pain sensitivity has been observed, and recent evidence suggests that some of the variability may be genetically mediated. Our previous data revealed significantly higher pressure pain thresholds among individuals possessing the minor G allele of the A118G SNP of the mu-opioid receptor gene (OPRM1) compared with those with 2 consensus alleles. Moreover, ethnic differences in pain sensitivity have been widely reported. Yet, little is known about the potential interactive associations of ethnicity and genotype with pain perception. This study aimed to identify ethnic differences in OPRM1 allelic associations with experimental pain responses. A total of 247 healthy young adults from three ethnic groups (81 African Americans; 79 non-white Hispanics; and 87 non-Hispanic whites) underwent multiple experimental pain modalities (thermal, pressure, ischemic, cold pressor). Few African Americans (7.4%) expressed the rare allele of OPRM1 compared to non-Hispanic whites and Hispanics (28.7% vs. 27.8%, respectively). Across the entire sample, OPRM1 genotype did not significantly affect pain sensitivity. However, analysis in each ethnic group separately revealed significant genotype effects for most pain modalities among non-Hispanic-whites (P<.05) but not Hispanics or African Americans. The G allele was associated with decreased pain sensitivity among whites only; a trend in the opposite direction emerged in Hispanics. The reasons for this dichotomy are unclear; they may involve ethnic differences in haplotypic structure, or A118G may be a tag-SNP linked to other functional polymorphisms. These findings demonstrate an ethnicity-dependent association of OPRM1 genotype with pain sensitivity. Additional research is warranted to uncover the mechanisms influencing these relationships.

Preoperative scar hyperalgesia is associated with post-operative pain in women undergoing a repeat Caesarean delivery

BACKGROUND

Over 1.4 million Caesarean deliveries are performed annually in the United States, out of which 30% are elective repeat procedures. Post-operative hyperalgesia is associated with an increased risk for persistent post-surgical pain; however, there are no data on whether residual scar hyperalgesia (SHA) from a previous Caesarean delivery (CD) persists until the next delivery. We hypothesized that residual SHA may be present in a substantial proportion of women and is associated with increased post-operative pain.

METHODS

One hundred and sixty-three women scheduled for a repeat CD under spinal anaesthesia were enrolled into the study. Mechanical temporal summation (mTS) and SHA index were measured preoperatively. SHA was considered present when the index was >0. Post-operative pain scores at 12, 24 and 48 h and wound hyperalgesia (WHA) at 48 h were recorded.

RESULTS

SHA was present in 67 women 41% with a median SHA index of 0.42 (Q (25)  = 0.25; Q (75)  = 1.1, range 0.03-4.25). Women with SHA had overall higher post-operative pain scores and SHA was correlated with preoperative mTS (r = 0.164, p < 0.05), post-operative pain severity (r = 0.25, p < 0.002) and WHA at 48 h (r = 0.608, p < 0.001). Severe pain (visual analogue pain scale-S48 ≥ 7, n = 20) was predicted with a sensitivity and specificity of 60% and 62%, respectively. Positive predictive value was 18% and negative predictive value was 92%.

CONCLUSIONS

Preoperative SHA is present in 41% of women scheduled for repeat CD and is associated with increased mTS and post-operative pain. Screening for preoperative SHA may predict women at risk for increased post-operative pain, and guide post-operative analgesia to include anti-hyperalgesic drugs.

Ethnic differences in pain and pain management

Considerable evidence demonstrates substantial ethnic disparities in the prevalence, treatment, progression and outcomes of pain-related conditions. Elucidating the mechanisms underlying these group differences is of crucial importance in reducing and eliminating disparities in the pain experience. Over recent years, accumulating evidence has identified a variety of processes, from neurophysiological factors to structural elements of the healthcare system, that may contribute to shaping individual differences in pain. For example, the experience of pain differentially activates stress-related physiological responses across various ethnic groups, members of different ethnic groups appear to use differing coping strategies in managing pain complaints, providers' treatment decisions vary as a function of patient ethnicity and pharmacies in predominantly minority neighborhoods are far less likely to stock potent analgesics. These diverse factors, and others may all play a role in facilitating elevated levels of pain-related suffering among individuals from ethnic minority backgrounds. Here, we present a brief, nonexhaustive review of the recent literature and potential physiological and sociocultural mechanisms underlying these ethnic group disparities in pain outcomes.

Associations between pro- and anti-inflammatory cytokine genes and breast pain in women prior to breast cancer surgery

The purposes of this study were to determine the occurrence rate for preoperative breast pain; describe the characteristics of this pain; evaluate for differences in demographic and clinical characteristics; and evaluate for variations in pro- and anti-inflammatory cytokine genes between women who did and did not report pain. Patients (n = 398) were recruited prior to surgery and completed self-report questionnaires on a number of pain characteristics. Genotyping was done using a custom genotyping array. Women (28.2%) who reported breast pain were significantly younger (P < .001); more likely to be nonwhite (P = .032); reported significantly lower Karnofsky Performance Status scores (P = .008); were less likely to be postmenopausal (P = .012); and had undergone significantly more biopsies (P = .006). Carriers of the minor allele for a single nucleotide polymorphism in interleukin (IL)1-receptor 1 (IL1R1) (rs2110726) were less likely to report breast pain prior to surgery (P = .007). Carriers of the minor allele for a single nucleotide polymorphism in IL13 (rs1295686) were more likely to report breast pain prior to surgery (P = .019). Findings suggest that breast pain occurs in over a quarter of women who are about to undergo breast cancer surgery. Based on phenotypic and genotypic characteristics found, inflammatory mechanisms contribute to preoperative breast pain.

PERSPECTIVE

In women with breast cancer, preoperative pain may be associated with increases in inflammatory responses associated with an increased number of biopsies. In addition, differences in cytokine genes may contribute to this preoperative breast pain.

Race and unequal burden of perioperative pain and opioid related adverse effects in children

BACKGROUND

Interindividual variability in pain perception and analgesic response is a major problem in perioperative practice. Adult studies suggest pain management is influenced by patient's race. The objective of this study is to evaluate the influence of race on perioperative pain treatment in children.

METHODS

Prospective observational study evaluating effect of race on analgesia and opioid related adverse effects after tonsillectomy in African American and Caucasian children. A sample of 194 healthy children between 6 and 15 years of age were included. Race was self-identified by parents. All participants received standard perioperative care with a standard anesthetic and an intraoperative dose of morphine. Analgesia outcomes included maximum postoperative pain scores, postoperative opioid requirement, and analgesic interventions. Safety outcomes included incidences of opioid related adverse effects.

RESULTS

African American children experienced significantly more postoperative pain than Caucasian children as measured by postoperative opioid requirement (P = .0011), maximum postoperative pain scores (P < .0001), and analgesic interventions (P < .0001) in the recovery room. Although Caucasian children received relatively less opioids perioperatively, they had significantly higher opioid related adverse effects (P = .039). African American children with obstructive sleep apnea were more likely to have prolonged post anesthesia recovery unit stay due to inadequate pain control.

CONCLUSIONS

After similar uses of intraoperative morphine for tonsillectomy, there was an unequal burden of increased pain in African American children and increased opioid adverse effects in Caucasian children in the recovery room. Though Caucasian children received relatively less opioids perioperatively, they had higher incidences of opioid related adverse effects than African American children.

Effects of genetic variation in H3K79 methylation regulatory genes on clinical blood pressure and blood pressure response to hydrochlorothiazide

BACKGROUND

Nearly one-third of the United States adult population suffers from hypertension. Hydrochlorothiazide (HCTZ), one of the most commonly used medications to treat hypertension, has variable efficacy. The renal epithelial sodium channel (ENaC) provides a mechanism for fine-tuning sodium excretion, and is a major regulator of blood pressure homeostasis. DOT1L, MLLT3, SIRT1, and SGK1 encode genes in a pathway that controls methylation of the histone H3 globular domain at lysine 79 (H3K79), thereby modulating expression of the ENaCα subunit. This study aimed to determine the role of variation in these regulatory genes on blood pressure response to HCTZ, and secondarily, untreated blood pressure.

METHODS

We investigated associations between genetic variations in this candidate pathway and HCTZ blood pressure response in two separate hypertensive cohorts (clinicaltrials.gov NCT00246519 and NCT00005520). In a secondary, exploratory analysis, we measured associations between these same genetic variations and untreated blood pressure. Associations were measured by linear regression, with only associations with P ≤ 0.01 in one cohort and replication by P ≤ 0.05 in the other cohort considered significant.

RESULTS

In one cohort, a polymorphism in DOT1L (rs2269879) was strongly associated with greater systolic (P = 0.0002) and diastolic (P = 0.0016) blood pressure response to hydrochlorothiazide in Caucasians. However, this association was not replicated in the other cohort. When untreated blood pressure levels were analyzed, we found directionally similar associations between a polymorphism in MLLT3 (rs12350051) and greater untreated systolic (P < 0.01 in both cohorts) and diastolic (P < 0.05 in both cohorts) blood pressure levels in both cohorts. However, when further replication was attempted in a third hypertensive cohort and in smaller, normotensive samples, significant associations were not observed.

CONCLUSIONS

Our data suggest polymorphisms in DOT1L, MLLT3, SIRT1, and SGK1 are not likely associated with blood pressure response to HCTZ. However, a possibility exists that rs2269879 in DOT1L could be associated with HCTZ response in Caucasians. Additionally, exploratory analyses suggest rs12350051 in MLLT3 may be associated with untreated blood pressure in African-Americans. Replication efforts are needed to verify roles for these polymorphisms in human blood pressure regulation.

Gender role affects experimental pain responses: a systematic review with meta-analysis

Gender role refers to the culturally and socially constructed meanings that describe how women and men should behave in certain situations according to feminine and masculine roles learned throughout life. The aim of this meta-analysis was to evaluate the relationship between gender role and experimental pain responses in healthy human participants. We searched computerized databases for studies published between January 1950 and May 2011 that had measured gender role in healthy human adults and pain response to noxious stimuli. Studies were entered into a meta-analysis if they calculated a correlation coefficient (r) for gender role and experimental pain. Searches yielded 4465 'hits' and 13 studies were eligible for review. Sample sizes were 67-235 participants and the proportion of female participants was 45-67%. Eight types of gender role instrument were used. Meta-analysis of six studies (406 men and 539 women) found a significant positive correlation between masculine and feminine personality traits and pain threshold and tolerance, with a small effect size (r = 0.17, p = 0.01). Meta-analysis of four studies (263 men and 297 women) found a significant negative correlation between gender stereotypes specific to pain and pain threshold and tolerance, with a moderate effect size (r = -0.41, p < 0.001). In conclusion, individuals who considered themselves more masculine and less sensitive to pain than the typical man showed higher pain thresholds and tolerances. Gender stereotypes specific to pain scales showed stronger associations with sex differences in pain sensitivity response than masculine and feminine personality trait scales.

A quantitative review of ethnic group differences in experimental pain response: do biology, psychology, and culture matter?

OBJECTIVE

Pain is a subjectively complex and universal experience. We examine research investigating ethnic group differences in experimental pain response and factors contributing to group differences.

METHOD

We conducted a systematic literature review and analysis of studies using experimental pain stimuli to assess pain sensitivity across multiple ethnic groups. Our search covered the period from 1944 to 2011, and used the PubMed bibliographic database; a reference source containing over 17 million citations. We calculated effect sizes; identified ethnic/racial group categories, pain stimuli, and measures; and examined findings regarding biopsychosociocultural factors contributing to ethnic/racial group differences.

RESULTS

We found 472 studies investigating ethnic group differences and pain. Twenty-six of these met our review inclusion criteria of investigating ethnic group differences in experimental pain. The majority of studies included comparisons between African Americans (AA) and non-Hispanic Whites (NHW). There were consistently moderate to large effect sizes for pain tolerance across multiple stimulus modalities; AA demonstrated lower pain tolerance. For pain threshold, findings were generally in the same direction, but effect sizes were small to moderate across ethnic groups. Limited data were available for suprathreshold pain ratings. A subset of studies comparing NHW and other ethnic groups showed a variable range of effect sizes for pain threshold and tolerance.

CONCLUSION

There are potentially important ethnic/racial group differences in experimental pain perception. Elucidating ethnic group differences has translational merit for culturally competent clinical care and for addressing and reducing pain treatment disparities among ethnically/racially diverse groups.

Mental health service utilization for psychiatric disorders among Latinos living in the United States: the role of ethnic subgroup, ethnic identity, and language/social preferences

PURPOSE

To examine aspects of Latino experience in the US as predicting service utilization for mood, anxiety, and substance disorders.

METHODS

Latino participants 18 and older in the NESARC (N = 6,359), a US national face to face survey. Outcomes were lifetime service utilization for DSM-IV lifetime mood/anxiety or substance disorders, diagnosed via structured interview (AUDADIS-IV). Main predictors were ethnic subgroup, ethnic identity, linguistic/social preferences, nativity/years in the US, and age at immigration.

RESULTS

Higher levels of Latino ethnic identity and Spanish language/Latino social preferences predicted lower service utilization for mood disorders [ethnic identity OR = 0.52, language/social OR = 0.44] and anxiety disorders [ethnic identity OR = 0.67, language/social OR = 0.47], controlling for ethnic subgroup, disorder severity, time spent in the US, and economic and practical barriers Service utilization for alcohol/drug disorders was low across all Latino subgroups, without variation by examined predictors.

CONCLUSION

Ethnic/cultural factors are strong determinants of service utilization for mood/anxiety, but not substance use disorders among Latinos in the US strategies to increase service utilization among Latinos with psychiatric disorders should be disorder specific, and recognize the role of ethnicity and identity as important components of a help-seeking model.

Expert panel consensus recommendations for the pharmacological treatment of acute pain in the Middle East region

The findings of an expert panel convened to review critically how best to apply evidence-based guidelines for the treatment of acute pain in the Middle East region are presented. The panel recommended a three-step treatment protocol. Patients with mild-to-moderate levels of acute pain should be treated with paracetamol (step 1). If analgesia is insufficient after 1-2 days, a selective cyclo-oxygenase-2 inhibitor or, if gastrointestinal safety and bleeding risk are not an issue, a non-specific nonsteroidal anti-inflammatory drug, should be used (step 2). If analgesia remains inadequate, treatment with tramadol, or paracetamol plus codeine/tramadol is recommended (step 3). Patients reporting severe pain should be referred to a pain clinic or specialist for opioid analgesic treatment. Measures of pain and functioning that have been validated in Arabic, with culturally appropriate and easy to understand descriptors, should be used. Early and aggressive acute pain management is important to reduce the risk of pain becoming chronic, especially in the presence of neuropathic features.

Assessment of the analgesic effect of remifentanil using three pain models in healthy Korean volunteers: a randomized, controlled study

Quantitative pain assessment in human beings is useful for developing new analgesics. This study assessed the analgesic effect of remifentanil in 20 healthy Korean men using three pain models to investigate whether these models can be used in Asians. The study was a double-blind, placebo-controlled, two-way cross-over study. The subjects received intravenous remifentanil with doses starting at 0.01 μg/kg/min. and increasing by 0.01 μg/kg/min. up to 0.10 μg/kg/min. in one session; they received placebo in another session. Heat pain thresholds were assessed at dose levels of 0.02, 0.05, 0.08 and 0.10 μg/kg/min. Pressure pain threshold and tolerance and mechanical pain threshold were assessed at 0.08 μg/kg/min. Remifentanil dose-dependently increased the heat pain threshold. The differences (95% confidence interval) between remifentanil and placebo were 1.54°C (0.78, 2.31), 1.82°C (1.11, 2.54) and 2.47°C (1.55, 3.38) at 0.05, 0.08 and 0.10 μg/kg/min. remifentanil, respectively. Remifentanil conferred a significantly higher pressure pain threshold and tolerance than placebo (p = 0.0001). There was a trend of increasing mechanical pain threshold with remifentanil, although it was not statistically significant. The results suggest that heat pain and pressure pain models are valid in East Asians for assessing analgesic effects.