Gender variations in clinical pain experience

Cyclical mastalgia: premenstrual syndrome or recurrent pain disorder?

Approximately 8-10% of premenopausal women experience moderate to severe perimenstrual breast pain or cyclical mastalgia, monthly. This mastalgia can occur regularly for years until menopause, can interfere with usual activities, and is associated with elevated utilization of mammography among young women. Although mastalgia is a well documented symptom in premenstrual syndrome (PMS), it is unknown whether PMS is necessarily present in women with cyclical mastalgia. The present study prospectively examined mastalgia and its relationship to PMS. Thirty-two premenopausal women reporting recent mastalgia completed breast pain and menstrual symptom scales daily for 3-6 months. Eleven women (34.4%) met criteria for clinically significant cyclical mastalgia, reporting an average of 10.2 days of moderate-severe mastalgia monthly. Five women (15.6%) met criteria for PMS. Mastalgia was not significantly associated with PMS: 82% of women with clinical cyclical mastalgia did not have PMS. Cyclical mastalgia, although by definition associated with the menstrual cycle, is not simply premenstrual syndrome, and merits further investigation as a recurrent pain disorder whose presentation, etiology, and effective treatment are likely to differ from those of PMS.

Everyday life with osteoarthritis or rheumatoid arthritis: independent effects of disease and gender on daily pain, mood, and coping

The effects of disease (form of arthritis) and gender on pain, mood, and pain coping strategies were examined in a prospective 30-day diary study of 71 patients with osteoarthritis (OA) and 76 with rheumatoid arthritis (RA). Diary instruments included joint pain ratings, POMS-B checklists for positive and negative mood, and the Daily Coping Inventory. Women's average daily pain was 72% greater than men's pain, and RA patients' average daily pain was 42% greater than OA patients' pain. Hierarchical Linear Models were estimated for (a) within-person associations between pain and next-day mood; coping and next-day pain; and coping and next-day mood; and (b) the independent effects of disease and gender on individual intercepts for pain, mood, and coping and on individual slopes for pain-coping-mood relations. Women, regardless of their disease, and RA patients, regardless of their gender, reported more daily pain. Women used more emotion-focused strategies each day than did men, regardless of their disease and even after controlling for their greater pain. Men were more likely than women to report an increase in negative mood the day after a more painful day. RA patients' pain worsened, but OA patients' pain improved, following a day with more emotion-focused coping. Implications for research and clinical practice are summarized.

Knowledge about pain among newly graduated occupational therapists: relevance for curriculum development

In recent years there has been a growing awareness amongst health professionals of the need to prepare undergraduate students more adequately for practice with clients who have pain. Occupational therapists have a central role in enabling such clients to have productive lives despite pain. In this study, an examination was made of the adequacy of preparation for pain practice in graduates from one Australian occupational therapy curriculum. Recent occupational therapy graduates from the University of Queensland, Australia, who responded to a postal survey, obtained an overall 53% correct response rate to a 69-item pain knowledge and attitudes questionnaire. Results indicated the need for further education in this area, especially in the areas of pharmacological management, and pain assessment and measurement. These results were comparable to those obtained from final year occupational therapy students at Dalhousie University in Halifax, Nova Scotia prior to undertaking an elective course about pain. Follow-up interviews with a number of new graduates supported the inclusion of an elective pain course in the undergraduate occupational therapy curriculum at the University of Queensland in Australia.

The kappa opioid nalbuphine produces gender- and dose-dependent analgesia and antianalgesia in patients with postoperative pain

Nalbuphine, pentazocine, and butorphanol, mixed agonist/antagonist opioids that induce analgesia by acting predominantly at kappa opioid receptors, have recently been shown in single-dose studies to have greater analgesic efficacy in women than in men. In the current experiments, the first placebo controlled dose response study of opioid analgesic efficacy that examines for gender differences, nalbuphine (5, 10, or 20 mg) and placebo were evaluated in 62 men and 69 women for the treatment of moderate to severe postoperative pain following extraction of impacted wisdom teeth. In a randomized, open injection, double blind experimental design, pain intensity was recorded on a 10 cm visual analog scale (VAS) immediately prior to drug administration (baseline) and at 20 min intervals thereafter. Although responses to placebo were similar in men and women, for all doses of nalbuphine women exhibited significantly greater analgesic response than men, compatible with our previous results. Unexpectedly, men receiving the 5 mg dose of nalbuphine experienced significantly greater pain than those receiving placebo; only the 20 mg dose of nalbuphine in men produced significant analgesia compared to placebo. While a similar antianalgesic effect was not observed in women, only the 10 mg dose of nalbuphine produced significant analgesia compared to placebo. These results suggest that the optimal analgesic dose of nalbuphine for women is lower than the highest dose that can be safely administered. In contrast, the antianalgesic effect of nalbuphine suggests avoidance of its routine use for postoperative analgesia in men until further studies clarify this issue. Because gender differences in other mixed kappa agonists/antagonists (i.e. pentazocine and butorphanol) have previously been shown, these results may generally apply to this class of opioid analgesics.

A comparison of faces scales for the measurement of pediatric pain: children's and parents' ratings

Faces scales have become the most popular approach to eliciting children's self-reports of pain, although different formats are available. The present study examined: (a) the potential for bias in children's self-reported ratings of clinical pain when using scales with smiling rather than neutral 'no pain' faces; (b) levels of agreement between child and parent reports of pain using different faces scales; and (c) preferences for scales by children and parents. Participants were 75 children between the ages of 5 and 12 years undergoing venepuncture, and their parents. Following venepuncture, children and parents independently rated the child's pain using five different randomly presented faces scales and indicated which of the scales they preferred and why. Children's ratings across scales were very highly correlated; however, they rated significantly more pain when using scales with a smiling rather than a neutral 'no pain' face. Girls reported significantly greater levels of pain than boys, regardless of scale type. There were no age differences in children's pain reports. Parents' ratings across scales were also highly correlated; however, parents also had higher pain ratings using scales with smiling 'no pain' faces. The level of agreement between child and parent reports of pain was low and did not vary as a function of the scale type used; parents overestimated their children's pain using all five scales. Children and parents preferred scales that they perceived to be happy and cartoon-like. The results of this study indicate that subtle variations in the format of faces scales do influence children's and parents' ratings of pain in clinical settings.

Temporomandibular disorders: a review of current understanding

OBJECTIVE

The purpose of this article is to conduct a narrative review of current evidence regarding the understanding, evaluation, management, and treatment of temporomandibular disorders to provide a broad perspective and updated introduction to an important and controversial subject with rapidly changing developments and limited well-designed research.

DATA SOURCES

Studies were identified through a search of MEDLINE for 3 topics (temporomandibular disorder, temporomandibular joint, and chronic pain) over a 10-year period (January 1988 to August 1998) and of bibliographies of identified studies and review articles.

STUDY SELECTION

More than 5000 articles were produced. In-depth review of all of this literature was beyond the scope of the present article, which is intended to provide an overview. The amount and diversity of the literature and the limitations of covering such a broad topic being recognized, the papers selected were those that reviewed limited topics or studied focused areas. This report is not a systematic (qualitative) or meta-analysis (quantitative) review. An acknowledged limitation of this narrative review method lies in the potential for bias in selection. The referenced works do not include all papers reviewed; only pertinent literature and reviews with comprehensive references were selectively included.

CONCLUSIONS

Advances in basic and clinical science have resulted in important changes in the understanding and management of temporomandibular disorders. Many treatments are not supported by research, and the role of dentistry is changing to a more diagnostic and management-based model from the hands-on treatment procedures of the past. The present science-based understand-ing of a biopsychosocial disorder is important in properly and responsibly dealing with patients with temporomandibular disorders.

Factors associated with analgesic and psychotropic medications use by community-dwelling older people with chronic pain

OBJECTIVE

The present study sought to examine use prevalence and factors associated with use of analgesic and psychotropic medications in community-dwelling older people with chronic non-malignant pain.

METHOD

The study group comprised 193 community-dwelling older people with daily chronic non-malignant pain who were selected from a random sample of 1,000 older people in Melbourne.

RESULTS

The use prevalence for the study group was 63% for analgesics and 39% for psychotropic medications, which is higher than the general older population without chronic pain (p < 0.00001). More women with chronic pain used analgesics, while psycho-social factors such as problems with sleeping and living at home alone were found to be associated with an increased use of psychotropic medications.

CONCLUSION

A high proportion of community-dwelling older people with chronic non-malignant pain use analgesic and psychotropic medications.

IMPLICATIONS

These findings provide the basis for further investigation into the level and appropriateness of analgesic and psychotropic medication use by older people with chronic pain.

Gender differences in pain

A literature survey reveals clear evidence of sex differences in the incidence of painful conditions and their severity, both being greater in women. The possible causes of this sexual dimorphism are discussed. Sex-role stereotyping may be relevant and there is evidence to indicate that, perhaps through their roles as carers, women seek and utilize more medical services than men. Less clear-cut evidence for anatomical and physiological differences is reviewed, together with documentation of hormonal (and reproductive cycle) influences on the operation of those systems.

Effects of gender and acute dental pain on thermal pain responses

OBJECTIVE

Considerable research suggests that females exhibit greater sensitivity to laboratory pain procedures than do males; however, whether the presence of acute clinical pain influences this sex difference in pain sensitivity has not been investigated. The present experiment investigated the effects of sex and acute dental pain on laboratory pain responses.

DESIGN

Thermal pain onset and tolerance were determined in 46 dental patients (15 male, 31 female) experiencing pain due to acute irreversible pulpitis and in 33 healthy controls (13 male, 20 female). In addition, measures of mood and coping were obtained in all participants. All subjects participated in two experimental sessions. The first session took place immediately before the patients underwent endodontic treatment for relief of pulpal pain. The second session took place approximately 1-2 weeks later, when pulpitis patients were pain free after treatment. During each session, thermal pain onset and tolerance were assessed with a 1-cm2 contact thermode applied to the right volar forearm using an ascending method of limits.

RESULTS

During both sessions, thermal pain onset and tolerance were lower in control females than in control males; however, male and female pulpitis patients did not differ in their thermal pain responses during either session. Pulpitis patients also showed greater affective distress than controls.

CONCLUSIONS

These data suggest that the sex difference in thermal pain sensitivity frequently reported in pain-free subjects appears to be absent in patients presenting with acute dental pain. However, this effect cannot be explained solely based on the presence of clinical pain because the effect on pain threshold and tolerance persisted into session 2, when pulpitis patients were pain free. Potential explanations for these results are discussed.

Does sex make a difference in the prescription of treatments and the adaptation to chronic pain by cancer and non-cancer patients?

The literature suggests that the sex of patients is an important factor in understanding how they are treated by health care professionals and how they adapt to their symptoms. In two groups of patients with chronic pain (n = 428 non-cancer (Study 1) and n = 143 cancer-related (Study 2)), men and women were compared on medications prescribed, treatment history, and coping and adaptation. In Study 1 with the non-cancer pain patients, there were no significant differences between the sexes in past treatments, current analgesic use, pain, or disability. Women were significantly more depressed and were more likely to receive antidepressants than men. Subgrouping patients on the basis of pain-adaptation responses yielded groups with distinct psychosocial and behavioral characteristics. In Study 2 with the cancer pain patients, men and women did not show significant differences on any variables. Consistent with the results of Study 1, however, psychological subgroups differed significantly in pain severity, mood and disability regardless of sex. The results of both studies suggest that the role of patients' sex in chronic pain may be less important than their psychosocial and behavioral responses. Thus, it appears that knowing the psychological characteristics of patients may be more important than their sex.

Long-term codeine use is associated with depressive symptoms

A community survey was conducted among long-term (>6 months) users of codeine-containing products to characterize chronic use of these extensively consumed medications. Respondents recruited through newspaper advertisements completed a mailed questionnaire. Three hundred thirty-nine completed questionnaires were obtained, yielding a response rate of 70%. Codeine dependence/abuse as defined by DSM-IV criteria was present in 41% of the respondents. Two thirds of the subjects had sought help for mental health problems, most often depression (70%). Scores on the Symptom Checklist-90 subscales were modestly elevated, particularly on the Depression subscale (1.2 +/- 0.9). Long-term codeine use is strongly associated with dependence. Depression and depressive symptoms are common. These data suggest that dysphoric mood states may be significant in maintaining long-term codeine use.

Anger in chronic pain: investigations of anger targets and intensity

The study was designed to assess the frequency and intensity of patients' anger directed toward various potential targets and how intensity of anger toward different targets was related to the chronic pain experience. Ninety-six chronic pain patients who were referred for a comprehensive evaluation completed questionnaires to assess their levels of anger, pain, distress, and disability. Approximately 70% of the participants reported to have angry feelings. Most commonly, patients reported to be angry with themselves (74%) and health care professionals (62%). The relevance of anger to chronic pain experience seemed to vary across targets. Anger toward oneself was significantly associated with pain and depression, whereas only overall anger was significantly related to perceived disability. The results suggest that anger should be conceptualized as a multifactorial construct. In addition to presence, intensity, and expression of anger, targets of anger may be important to better understand psychological adaptation to chronic pain.

Procedural pain in newborn infants: the influence of intensity and development

OBJECTIVE

Previous reports have shown that pain is managed inadequately in newborn infants. Ironically, clinicians believe that infants can experience pain much like adults, that infants are exposed daily to painful procedures, and that pain protection should be provided. In adults, a close relationship has been shown in how adults behave in response to pain, how painful they sense the stimulus to be, and physical measurements of the intensity of the stimulus. Whether similar parallels exist in newborn infants has not been examined. If these parallels do not exist in infants, it may help explain why clinicians fail to manage procedural pain in infants more effectively. The objective of this study was to determine whether the magnitude of infants' responses to nursing/medical procedures: 1) differs as a function of the invasiveness or intensity of the procedure; 2) differs as a function of intrauterine (gestational age at birth) and/or extrauterine (conceptional age) development; and 3) parallels the subjective pain ratings of clinicians for those procedures.

METHODS

A broad developmental and clinical range of newborn infants was studied shortly before (baseline and preparatory periods), throughout, and shortly after (recovery period) required nursing/medical procedures during hospitalization. Heart rate, oxygen saturation, mean arterial pressure, and behavioral state (percentage of time spent in sleep or in agitation) were measured, and the magnitude of change in each in response to procedures was calculated. Procedures were categorized as mildly, moderately, and highly invasive to examine differences in response magnitude as a function of procedural invasiveness. Responses were compared as a function of prematurity and postnatal age. Clinicians' procedural pain ratings were compared with the magnitude of infants' responses.

RESULTS

Of the original 152 infants, 135 were studied at least two times (range 2-27). Significant changes occurred in physiologic and behavioral measures in response to procedures indicative of pain responses. The magnitude of response generally increased with increased procedural invasiveness although there was considerable overlap of magnitude with invasiveness. Both premature and full-term infants differentiated procedural invasiveness. Very premature infants (<28 weeks' gestational age) exhibited increased increments in response magnitude with increasing postnatal age. Clinician's ratings of procedural painfulness were correlated with and predicted the magnitude of heart rate response to individual procedures.

CONCLUSIONS

Similar to what has been shown in adults, newborn and developing infants show increased magnitude physiologic and behavioral responses to increasingly invasive procedures, demonstrating that even very prematurely born infants respond to pain and differentiate stimulus intensity. However, the considerable overlap of magnitude with invasiveness suggests that there is not a physiologic or behavioral threshold that clearly marks the presence of pain. Inconsistencies in physiologic and behavioral responses make reliance on a pain index difficult. The best approach may be one of universal precaution to provide pain management systematically to reduce the acute and long-term impact of early procedural pain. development, stimulus intensity, pain response.

The relationship between chronic facial pain and a history of trauma and surgery

OBJECTIVE

Because pain is the most commonly reported symptom of patients presenting to temporomandibular disorders clinics, it is important to identify factors that modify the perception or reality of such pain. The purpose of this study was to investigate the hypothesis that a patient with a history of trauma and/or non-temporomandibular joint surgery might be sensitized to pain and might report increased pain levels if a temporomandibular disorder later developed.

STUDY DESIGN

This was a retrospective study of 778 consecutive patients seen over a 1-year period in an Orofacial Pain Clinic. Study parameters included gender, lifetime number of self-reported traumas, lifetime number of non-temporomandibular joint operations, and location, intensity, frequency, and type of temporomandibular disorder-related pain.

RESULTS

There were significantly more women than men in the study (609 to 169). There was no relationship between numbers of previous traumas and non-temporomandibular joint operations and types of temporomandibular disorder. However, there were statistically significant relationships between the severity of facial pain and the frequency of facial pain as well as between the severity and frequency of joint pain and the number of traumas. There were also statistically significant associations between the severity and frequency of facial pain and the number of non-temporomandibular joint-related surgical procedures that the patient had undergone.

CONCLUSIONS

There is a relationship between a patient's reported history of trauma and/or non-temporomandibular joint-related operations and the severity and frequency of facial and temporomandibular joint pain, should it develop. It is possible that such traumas and operations sensitize the patient in such a way that the pain of subsequent temporomandibular joint disorders is heightened.

Pain after periodontal scaling and root planing

BACKGROUND

Although periodontal scaling and root planing, or SRP, is one of the most common procedures used in dental practice, there is little information available about the degree of postprocedural pain associated with it. The authors undertook this study to document the intensity and duration of pain after SRP with a view toward helping practitioners and their patients manage postprocedural discomfort.

METHODS

Using the Heft-Parker self-assessment pain scale, 52 adults with moderate periodontitis evaluated their pain before and after SRP conducted with local anesthetic.

RESULTS

After SRP, 28 percent of all patients reported faint-to-weak pain, 18 percent experienced weak-to-mild pain, 28 percent experienced mild-to-moderate pain, 8 percent had moderate-to-strong pain and 8 percent reported strong-to-intense pain. The average time to onset of maximum pain was approximately three hours after SRP, and the average duration of mild or greater pain was about six hours. Upon awakening the morning after SRP, subjects found that pain had returned to pre-SRP levels. Overall, 23 percent of all patients reported self-medicating with analgesics to relieve postprocedural pain. Women self-medicated earlier (P < .05) and more often than men (43 percent vs. 10 percent; P < .05).

CONCLUSIONS

Patients experienced significant duration and magnitude of pain after SRP. This pain peaked between two and eight hours after SRP, lasted about six hours, and returned to pre-SRP levels by the morning after the procedure. Almost 25 percent of all patients self-medicated to relieve pain after SRP, and women took analgesic medication earlier and more often than men.

CLINICAL IMPLICATIONS

Practitioners should consider using appropriate analgesic drugs to alleviate mild-to-moderate pain after SRP. On the basis of this study, it would appear that an analgesic that has a peak effect two to eight hours after the completion of SRP would be the most appropriate medication. Moreover, it is unlikely that analgesic medication would be needed by most patients beyond the day on which SRP was performed.

Low hot pain threshold predicts shorter time to exercise-induced angina: results from the psychophysiological investigations of myocardial ischemia (PIMI) study

OBJECTIVES

The purpose of this study was to test whether cutaneous thermal pain thresholds are related to anginal pain perception.

BACKGROUND

Few ischemic episodes are associated with angina; symptoms have been related to pain perception thresholds.

METHODS

A total of 196 patients with documented coronary artery disease underwent bicycle exercise testing and thermal pain testing. The Marstock test of cutaneous sensory perception was administered at baseline after 30 min of rest on two days and after exercise and mental stress. Resting hot pain thresholds (HPTs) were averaged for the two baseline visits and divided into two groups: 1) average HPT <41 degrees C, and 2) average HPT > or =41 degrees C, to be clearly indicative of abnormal hypersensitivity to noxious heat.

RESULTS

Patients with HPT <41 degrees C had significantly shorter time to angina onset on exercise testing than patients with HPT > or =41 degrees C (p < 0.04, log-rank test). Heart rates, systolic blood pressure and rate-pressure product at peak exercise were not different for the two groups. Resting plasma beta-endorphin levels were significantly higher in the HPT <41 degrees C group (5.9+/-3.7 pmol/liter vs. 4.7+/-2.8 pmol/liter, p = 0.02). Using a Cox proportional hazards model, patients with HPT <41 degrees C had an increased risk of angina (p = 0.03, rate ratio = 2.0). These differences persisted after adjustment for age, gender, depression, anxiety and history of diabetes or hypertension (p < 0.01).

CONCLUSIONS

Occurrence of angina and timing of angina onset on an exercise test are related to overall hot pain sensory perception. The mechanism of this relationship requires further study.

Sex differences in late behavioral response to subcutaneous formalin injection in mice

We investigated sex- or gender-dependent differences in nociception using the formalin test in mice. In addition to typical biphasic responses, a new, late phase (Phase 3) was observed. A local anesthetic QX-314 injected at the end of Phase 2 blocked Phase 3. Phase 3 in female mice was significantly greater than that in male mice regardless the stage of the estrus cycle.

Review article: gender-related differences in functional gastrointestinal disorders

Many functional gastrointestinal disorders and other chronic visceral pain disorders such as interstitial cystitis and chronic pelvic pain are more common in women than in men. In irritable bowel syndrome (IBS) there is a 2:1 female to male ratio in prevalence of symptoms in community samples. Female irritable bowel syndrome patients are more likely to be constipated, complain of abdominal distension and of certain extracolonic symptoms. While animal studies have clearly demonstrated gender-related differences in pain perception and antinociceptive mechanisms, unequivocal evidence for gender-related differences in human pain perception or modulation has only been provided recently. Gender-related differences may be related to constant differences in the physiology of pain perception, such as structural or functional differences in the visceral afferent pathways involved in pain transmission or modulation, and/or they may be related to fluctuations in female sex hormones. Preliminary evidence suggests that female irritable bowel syndrome patients show specific perceptual alterations in regards to rectosigmoid balloon distension and that they show differences in regional brain activation measured by positron emission tomography. This preliminary evidence suggests that gender-related differences in symptoms and in the perceptual responses to visceral stimuli exist in IBS patients and can be detected using specific stimulation paradigms and neuroimaging techniques.

Does gender affect appraisal of pain and pain coping strategies?

OBJECTIVE

To investigate the impact of gender and a set of pain characteristics on the threat or challenge appraisal of pain and the impact of these appraisals on the coping strategies used to manage the pain.

DESIGN

This study used a community telephone survey to examine these relationships for a troublesome pain experienced by respondents in the 2 weeks preceding the interview. STUDY RESPONDENTS: The sampling frame consisted of 1,430 households randomly selected from the Halifax-Dartmouth-Bedford community. Of the 390 respondents with a troublesome pain in the 2 weeks preceding the interview, 309 respondents agreed to participate (79% response rate).

RESULTS

Women tended to report more pain located in the head and more somatic problems. They reported significantly more intense pain. For women and men, the most important impact on threat appraisal of pain was overall interference of pain and emotional upset due to pain. These two variables accounted for 48% of the variance in threat appraisal for women and 37% of the variance for men. There was no gender difference in emotional upset due to pain or in the impact of emotional upset on threat appraisal. There was no gender difference in challenge appraisal. Threat appraisal was associated with increased catastrophizing whereas challenge appraisal was associated with positive self-statements. Women reported significantly more problem solving, social support, positive self-statements, and palliative behaviors than did men.

CONCLUSIONS

Interference of pain has a greater impact on threat appraisal of pain for women. Increasing threat appraisal is associated with health care utilization for women, but women's more frequent use of several coping strategies is unrelated to their appraisal of pain. Appraisal of pain may have important implications on coping and overall well-being of women and men.

[Prevalence and indirect costs of headache in a Brazilian Company]

Employees from a Brazilian oil company research centre (n = 993) were interviewed on the occurrence of headache during a 30 days period. Headache prevalence was 49.8%, with a mean frequency of 4.3 +/- 7.0 attacks per month, lasting 12.2 +/- 21.4 hours each. According to the International Headache Society diagnostic criteria, migraine (5.5%), episodic tension-type headache (26.4%), chronic tension-type headache (1.7%) and headaches not fulfilling the criteria for such disorders (16.2%) were observed. Women suffered comparatively more headache and specifically migraine than men. The pain interfered with work productivity in 10% of the subjects, corresponding to 538.75 hours off. According to an indirect costs estimation for each headache, the company may loose up to US$125.98 per employee annually. Since among headaches migraine has the highest indirect cost, migraine prevention and treatment is particularly important at the working environment. Migraine frequency may be prevented to a large extent, resulting on positive effects in both the quality of life and productivity. The cost-benefit ratio clearly favours therapeutic and preventive programs against chronic headaches.

Different types of steroids inhibit [3H]diprenorphine binding in mouse brain membranes

1. The binding of 60 drugs, mainly steroids, to opioid receptors was studied in crude membrane fractions from mouse brains. 2. Competition assays with the different drugs (5 x 10(-7)-10(-4)M) were performed by labeling opiate receptors with [3H]diprenorphine (0.3-0.4 nM). 3. Only 7 drugs (alpha,5beta-tetrahydrodeoxycorticosterone, megestrol acetate, mifepristone, 17alpha-ethynylestradiol, diethylstilbestrol, clomiphene citrate and tamoxifen citrate) inhibited [3H]diprenorphine binding more than 50% at the highest concentration assayed (10(-4) M). The IC50 values ranged between 6x10(-5) M. 4. Thus, the present results show that only a limited number of steroids, from diverse classes, bind to opiate receptors.

The meeting of pain and depression: comorbidity in women

The higher prevalence of depression in women is coupled with a higher prevalence of pain complaints. Growing evidence suggests that the comorbidity of these conditions is also proportionately higher in women than men. This paper critically reviews the empirical findings relating to gender differences in comorbid pain and depression as well as findings in support of hypothesized etiologic factors that could explain why women may be more susceptible than men to comorbidity. The empirical evidence for biogenic, psychogenic, and sociogenic explanatory models is presented, and an integration of these models is proposed as a guideline to both research and clinical practice. In conclusion, it is argued that gender-differentiated treatment strategies are not clinically indicated at this time.

Background pain in burn patients: routine measurement and recording of pain intensity in a burn unit

It goes without saying that pain following a burn must be treated but it is not so evident to measure and document the intensity of pain and the efficacy of treatment. Since 1994 the authors have routinely measured background pain, that is, at rest, along with temperature and pulse rate. For analysis and quality assessment a relational database programme is used in the ward. In this paper the authors' experience is reported from a consecutive series of 98 patients with burn injuries who assessed the intensity of pain on a visual analogue scale. There were great intra- and inter-individual variations in pain intensity. Highest values were found during the first week of treatment when female patients experienced pain more intensively than male. For other time periods there was no statistical significant difference between the sexes. Pain intensity and severity of burn was not related except during the second week when patients with major burns had a tendency to express more pain than moderate burns. Measurement of background pain along with other routine registrations is easy and not time-consuming. Patients needing intensified pain treatment can be identified. For research and quality assessment a computerized patient register is of great help.

The relationship between gender and family history of pain with current pain experience and awareness of pain in others

This study aimed to evaluate the relationship between family history of pain and current pain experience in a student population. In a sample of 180 students who completed a pain history questionnaire there was a significant difference between males and females with women reporting significantly more pain models than men even when menstrual pain models were excluded from the analysis. There was also a difference on current pain symptoms, with women reporting more pain symptoms but this difference was no longer significant when menstrual pain was excluded. These results suggest that differences observed between sexes in a young student population in relation to current pain symptom reports may be accounted for by the presence of menstrual pain rather than by differences in family history of pain as it has previously been suggested. The higher incidence of pain models reported by females for menstrual as well as non-menstrual pain suggests a greater awareness of pain in others without implying a greater tendency for the young females as a group to report pain themselves.

Chronic pain in a community-based sample of men with spinal cord injury: prevalence, severity, and relationship with impairment, disability, handicap, and subjective well-being

OBJECTIVE

To assess the prevalence, severity, and correlates of chronic pain in a community-based sample of men with spinal cord injury (SCI).

DESIGN

Survey.

SETTING

Community.

PARTICIPANTS

Seventy-seven men with SCI randomly selected from a sampling frame solicited from the community.

METHOD

Participants completed standardized questionnaires assessing many areas of life, were interviewed in their homes, and underwent a physical examination at a hospital. There they were interviewed by an anesthesiologist regarding chronic pain, and a nurse administered objective pain measures.

RESULTS

Seventy-five percent of the men reported chronic pain. Chronic pain was associated with more depressive symptoms, more perceived stress, and poorer self-assessed health. Greater intensity of pain was related to less paralytic impairment, violent etiology, and more perceived stress. Area of the body affected by pain was related to independence and mobility.

CONCLUSIONS

Because of the high prevalence of chronic pain in the population with SCI and its relation to disability, handicap, and quality of life, health care providers need to give this issue the same priority given to other SCI health issues. Analysis of individual pain components provides better information than assessing overall pain. It is futile to treat SCI pain without giving full attention to subjective factors.

The Pain Coping Questionnaire: preliminary validation

A new measure of coping, the Pain Coping Questionnaire (PCQ), is presented and validated in two studies of children and adolescents. Factor analyses of data from healthy children and adolescents supported eight hypothesized subscales (information seeking, problem solving, seeking social support, positive self-statements, behavioral distraction, cognitive distraction, externalizing, internalizing/catastrophizing) and three higher-order scales (approach, problem-focused avoidance, emotion-focused avoidance). The subscales and higher-order scales were internally consistent. The pain coping scales were correlated in the expected directions with children's appraisals of pain controllability, self-rated coping effectiveness, emotional distress when in pain, and among high school students, pain thresholds and functional disability. The structure and internal consistency of the PCQ were replicated in a sample of children and adolescents experiencing recurrent pain (headache, arthritis), and their parents. Relations between child- and parent-ratings of children's coping were moderate (median r=0.34). Higher levels of emotion-focused avoidance were related to more emotional distress (both samples), less coping effectiveness (headache sample), and higher levels of pain (arthritis sample). Higher levels of approach coping were related to less disability (headache sample). Other relations between approach and distraction coping and the outcome variables were generally not significant. The PCQ is a promising instrument for assessing children's pain coping strategies. The items are simple and relatively few, making it useful for assessing coping across a wide age range. It can be administered to children as young as 8 years of age in approximately 15 min.

Orofacial pain symptom prevalence: selective sex differences in the elderly?

This study investigated sex differences in orofacial pain symptoms in a sample of elderly adults. Furthermore, differences across sex were tested on symptom continuity, overall duration, pain severity, activity reduction, and health care utilization, related to each specific symptom. Telephone interviews were conducted with a stratified random sample of community dwelling older (65+) north Floridians. A total of 5860 households were contacted and screened, with 75.3% participating to the point where their eligibility for the study could be determined. Of the remaining households, 1636 completed the interview. Of the total sample, 17.4% reported experiencing at least one of the four target orofacial pain symptoms (jaw joint pain, face pain, oral sores, burning mouth) during the past year, suggesting that orofacial pain symptoms are common in older adults. Our findings for prevalence of each specific symptom (jaw joint pain, 7.7%; face pain, 6.9%; oral sores, 6.4%; toothache, 12.0%; burning mouth, 1.7%) are similar to those estimated by the 1989 National Health Interview Survey, for the US adult population. Consistent with other epidemiological and clinical studies, we found that females were more likely to report jaw joint pain and face pain than males. In contrast to clinical studies, no differences were found on subjective ratings of pain severity, for any symptom. Differences across sex were most likely to be reported for jaw joint pain related variables, suggesting undetermined sex-uniqueness for these symptoms. In contrast to previous studies, older females tended to report lower levels of health care utilization than older males. This is the first study to our knowledge that reports orofacial symptom-specific sex differences among the elderly.

Prescription and nonprescription analgesic use in Sweden

OBJECTIVE

To analyze patterns of prescription and nonprescription analgesic use in the general Swedish population, in association with predisposing factors, enabling factors, need, and health behavior.

DESIGN

Cross-sectional interview survey.

SETTING

The Swedish Surveys of Living Conditions for the 2-year period 1988-1989.

PARTICIPANTS

A probability sample of all inhabitants of Sweden aged 18-84 years (n = 11996).

MAIN OUTCOME MEASURES

Prescription and nonprescription analgesic use during a 2-week period.

RESULTS

Women reported use of analgesics both with and without prescriptions to a greater extent than did men. Among women, 12.2% reported prescription analgesic use and 30.4% reported nonprescription analgesic use. The corresponding proportions among men were 7.2% and 20.0%, respectively. In the descriptive analyses, prescription analgesic use was most common among persons aged 45 years and older, while use of nonprescription analgesics was most common in people aged 18-44 years. The polychotomous logistic regression analyses showed that headache and musculoskeletal pain were strongly associated with prescription analgesic use to a similar extent among men and women. Headache was associated with nonprescription analgesic use among men and women, but a gender difference was found in the association between musculoskeletal pain and nonprescription analgesic use. Women with musculoskeletal pain used nonprescription analgesics to a greater extent than did men with musculoskeletal pain. Poor health--measured as self-perceived health status and physical function--and high use of health care were related only to prescription analgesic use. Smoking and being overweight were associated with prescription analgesic use among men and with nonprescription analgesic use among women; alcohol consumption was associated with both types of analgesic use only among women.

CONCLUSIONS

This study shows that men and women differ in their choice between prescription and nonprescription analgesics and that the choice between prescription and nonprescription analgesics is influenced by an individual's pain, self-perceived health, and lifestyle.

Prediction and assessment of the severity of post-operative pain and of satisfaction with management

A prospective observational study of cohorts of patients undergoing hip replacement (30), knee replacement (31), and spinal nerve root decompressive surgery (30) were interviewed pre-operatively to identify factors which might correlate with and potentially predict severe post-operative pain and dissatisfaction with analgesic management. The hip patients comprised 33% females and averaged 64 years, while the knee patients were 45% female and older (mean 71 years) and the spinal patients were 43% female and averaged 50 years. The three groups were similar with respect to all other pre-operative variables. Pain intensity was assessed mainly by self-report using the Present Pain Intensity (PPI) and Visual Analogue Scales (VAS) of the McGill Pain Questionnaire. The PPI was preferred by patients and nurses and, as there were no analytical advantages for the VAS, the PPI data are presented. The average post-operative pain during routine management mainly with patient controlled intravenous opiate, was mild to moderate and declined over days 1-5, declined further at discharge but rose slightly 1 month after discharge. The hip replacement patients experienced significantly (P < 0.01) less pain overall than the patients in the other two groups. Nurses' assessments of pain severity from observed behaviour were low and agreed poorly with the patients' self reports. Assessed on Likert Scales (0-6), the patients generally indicated good or excellent pain control, better than expected pain experience, and high levels of satisfaction with analgesic management. Significant (P < or = 0.01) multivariate correlates of severe post-operative pain assessed by logistic regression analysis of 11 variables were female gender, high pre-operative pain severity, and younger age. Significant (P < or = 0.01) multivariate correlates of both worse than expected pain experience and low satisfaction were female gender, high pre-operative pain severity, high anxiety about risks and problems, low expected pain severity, age (younger) and high willingness to report pain. These variables may reasonably be tested in further studies as potential predictors of adverse post-operative pain experience.

Predictive factors and opioid responsiveness in cancer pain

The management of cancer pain not readily responsive to morphine is often problematic. Several factors can interfere with an appropriate analgesic opioid response in the course of the illness, including the progression of the disease and tolerance, the appearance of intractable side-effects, type and temporal pattern of pain, morphine metabolites, pharmacokinetic and pharmacodynamic factors, as well as individual factors. Different methodologies capable of accurately predicting or monitoring opioid response have been proposed in an attempt to allow researchers to 'speak a common language'. Tolerance is a component of the concept of opioid responsiveness. However, the assessment of analgesic tolerance in cancer patients is constrained by numerous difficulties because of the changes in the noxious stimuli with increasing activity in nociceptive pathways.

Evaluation of the Faces Pain Scale for use with the elderly

OBJECTIVE

The specific objective for this research was to determine initial psychometric properties of the Faces Pain Scale (FPS) as a measure of pain intensity for use with the elderly.

DESIGN

The study was descriptive correlational in nature, with nonrandom sampling. A total sample of 168 community subjects (30-121, depending on task completed), aged 65 or older, participated in the research protocol. To determine the validity, reliability, and scaling properties of the FPS, rating and ranking procedures, placement tasks, and test-retest methods were used.

RESULTS

Response to six Likert-type items indicated that subjects agreed that the FPS represents pain: however, it is clear that the perception of the meaning of the faces can be influenced by the context in which they are presented. Rank ordering tasks for the individual faces demonstrated near-perfect agreement between the actual expected ranking and the ranking produced by the subjects (Kendall's W = .97, p = .00). When subjects placed individual faces along a 1-m-long red wedge indicating the amount of pain represented by each face, statistically significant separation of the faces in the anticipated equal interval position was demonstrated by the lack of overlap of the 95% confidence intervals when all faces were viewed and positioned simultaneously. However, when subjects placed faces independent of others, the expected placement fell outside the 95% confidence limit for three of the five faces placed. In addition, the actual intervals between the five faces placed by subjects demonstrated substantial variances from the 167 mm expected in several instances. Rating a vividly remembered painful experience about the degree of pain perceived using the FPS initially and again 2 weeks later, the FPS demonstrated strong reproducibility over time with a Spearman rho correlation coefficient of .94 (p = .01).

CONCLUSION

These results provide preliminary support for the construct validity, strong ordinal properties, and strong test-retest reliability of the FPS with a sample of elderly individuals. The equality of intervals in the FPS has not been fully supported in the older adult, but given the complexity of the task used, the results should not be considered to be refuted. Further evaluation of the FPS with experimental and clinical pain conditions and comparison with other standard pain assessment instruments in the elderly population are warranted.

The effect of age and gender on the onset of symptomatic temporomandibular joint disk displacement

OBJECTIVE

The aim of this study was to test the hypotheses that incidence of symptomatic temporomandibular joint disk displacement is evenly distributed over all ages and between genders and that there is no gender difference in pain perception.

STUDY DESIGN

The study population consisted of 248 consecutive patients with radiographically verified symptomatic temporomandibular joint disk displacement. The time of onset of the condition relative to age and gender was determined, as was pain level.

RESULTS

There was a statistically significant peak in incidence of symptomatic temporomandibular joint disk displacement during adolescence for both genders. Teenage girls were found to run a risk of developing disk displacement that is three times greater than the risk for teenage boys, and girls were found to run a risk during puberty that is four times greater than their risk later in life. The age at onset of the condition did not differ between genders. Both female and male subjects reported the same degree of pain level.

CONCLUSION

The results point to a teenage preponderance and a sexual dimorphism with respect to incidence of symptomatic temporomandibular joint disk displacement.

Sex differences in the perception of noxious experimental stimuli: a meta-analysis

Fillingim and Maixner (Fillingim, R.B. and Maixner, W., Pain Forum, 4(4) (1995) 209-221) recently reviewed the body of literature examining possible sex differences in responses to experimentally induced noxious stimulation. Using a 'box score' methodology, they concluded the literature supports sex differences in response to noxious stimuli, with females displaying greater sensitivity. However, Berkley (Berkley, K.J., Pain Forum, 4(4) (1995) 225-227) suggested the failure of a number of studies to reach statistical significance suggests the effect may be small and of little practical significance. This study used meta-analytic methodology to provide quantitative evidence to address the question of the magnitude of these sex differences in response to experimentally induced pain. We found the effect size to range from large to moderate, depending on whether threshold or tolerance were measured and which method of stimulus administration was used. The values for pressure pain and electrical stimulation, for both threshold and tolerance measures, were the largest. For studies employing a threshold measure, the effect for thermal pain was smaller and more variable. The failures to reject the null hypothesis in a number of these studies appear to have been a function of lack of power from an insufficient number of subjects. Given the estimated effect size of 0.55 threshold or 0.57 for tolerance, 41 subjects per group are necessary to provide adequate power (0.70) to test for this difference. Of the 34 studies reviewed by Fillingim and Maixner, only seven were conducted with groups of this magnitude. The results of this study compels to caution authors to obtain adequate sample sizes and hope that this meta-analytic review can aid in the determination of sample size for future studies.

Sex-dependent effects of formalin and restraint on c-Fos expression in the septum and hippocampus of the rat

In the present study we have demonstrated that the same aversive stimulus induces different patterns of expression of transcription factors in the hippocampus and septum of male and female rats. We have investigated by immunohistochemistry the effects of a persistent painful stimulus and restraint stress on c-Fos expression in the hippocampus and septum of male and female rats. Subjects were randomly assigned to one of three experimental groups: (i) untreated controls, (ii) subcutaneous injection with formalin (50 microliters, 10%) in the right hindpaw, or (iii) immobilization in an adjustable restrainer. Formalin-treated and restrained animals were killed 90 min after the beginning of treatment. In both male and female rats, unilateral injection of formalin induced bilateral c-Fos expression in the hippocampus, but the number of labeled neurons was two-fold higher in females than in males. Restraint stress was not effective in c-Fos induction in the hippocampus of both sexes. In the septum, both treatments increased c-Fos, but this increase tended to be greater in males than females. Previous experiments have consistently shown that male and female rats react differently to aversive stimulation. The present findings suggest that hormonal and behavioral differences between the sexes are accompanied by genetic modifications in those brain areas involved in cognition and emotion.

Sex differences in pain-induced effects on the septo-hippocampal system

In addition to its role in the modulation of functions such as arousal and attention, learning and memory, the limbic system has repeatedly been described to be involved in the regulation of several behavioral aspects concerning the adaptation to aversive situations, including pain. A key role in these processes seems to be played by the septo-hippocampal system. This paper, far from being a comprehensive review of all the data available about the limbic system, describes some of the circuits participating in the septo-hippocampal system, with the aim of contributing to an understanding of the sex differences in the behavioral, hormonal and neuronal responses to aversive stimuli. It will appear that the complex anatomical and functional interactions between the different neurotransmitters acting at this level prevent one from indicating a certain substance as more important than others in determining a difference between the two sexes. This leads to the conclusion that the septo-hippocampal formation in toto plays a key role in determining the sex differences in the 'pain experience'.

Identification of a sex-specific quantitative trait locus mediating nonopioid stress-induced analgesia in female mice

It is increasingly appreciated that the sexes differ in their perception of noxious stimuli and in their responsivity to exogenous and endogenous analgesic manipulations. We previously reported the existence of qualitative sex differences in the neurochemical mediation of nonopioid (i.e., naloxone-insensitive) stress-induced analgesia (SIA) produced by forced swims and suggested that female mice possess a sex-specific SIA mechanism. This female-specific system is now known to be estrogen-dependent, to be ontogenetically organized, and to vary with reproductive status; however, its neurochemical identity remains obscure. In an attempt to identify candidate genes underlying SIA in both sexes, we performed a two-phase quantitative trait locus (QTL) mapping experiment using the BXD/Ty recombinant inbred (RI) set derived from DBA/2J (D2) and C57BL/6J (B6) inbred mouse strains and (B6xD2)F2 hybrid mice derived from these same progenitors. All mice were subjected to 3 min forced swims in 15 degrees C water; nociceptive sensitivity on the 54 degrees C hot-plate assay was assessed immediately before and 2 min after cessation of the swim. We report the localization of a QTL statistically associated with SIA magnitude [p = 0.00000012; logarithm of the odds (LOD) = 6.1] in female mice only. This female-specific QTL, which we name Fsia1, is located on chromosome 8 at 52-84 cM from the centromere and accounts for 17-26% of the overall trait variance in this sex. The present data provide further evidence of the existence of a female-specific SIA mechanism and highlight the important role of both genetic background and gender in the inhibition of pain.

Cyproterone acetate displaces opiate binding in mouse brain

Drugs acting on androgen receptors modify opioid transmission in the central nervous system. To investigate a direct interaction, we studied whether the binding of [3H]diprenorphine to mouse brain membranes was modified by cyproterone acetate (progesterone derivative with antiandrogen activity), flutamide (non-steroidal antiandrogen), 5alpha-dihydrotestosterone and progesterone. Only cyproterone acetate inhibited [3H]diprenorphine binding (IC50 = (1.62 +/- 0.33) x 10(-6) M) without modifying its association rate. These results suggest that cyproterone acetate binds to opiate receptors independently of its classical androgenic intracellular receptor effect.

Kappa-opioids produce significantly greater analgesia in women than in men

Sex differences in human responses to nociceptive stimuli and painful pathological conditions have generally indicated that women report higher pain levels or exhibit less tolerance than men for given stimulus intensities (reviewed in ref. 1 and 2). However, studies have not evaluated sex differences in analgesic responses. We recently reported that the opioid agonist-antagonist pentazocine, which acts predominantly at kappa-receptors, produced significantly better postoperative analgesia in females than in males in patients who underwent surgery for the removal of their third molars (wisdom teeth). In the current study, we evaluated the hypothesis that this sex difference is a characteristic of kappa-opioid agonism. In order to determine whether there are sex differences associated with kappa-opioid agonism, the analgesic efficacy of two other predominantly kappa-opioid analgesics, nalbuphine and butorphanol; was compared in males and females who underwent surgery for the removal of third molar teeth. We found that both nalbuphine and butorphanol produced significantly greater analgesia in females as compared with males. Considering our earlier findings, we conclude that kappa-opioid analgesia is greater in females than in males, probably reflecting a difference in kappa-opioid-activated endogenous pain modulating circuits.