The journal of pain : official journal of the American Pain Society
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Using a simple approach for coding pain severity, the present study describes self-reported pain in U.S. adults. Data are included for 8,781 adults who completed the Functioning and Disability Supplement of the 2012 National Health Interview Survey. An internationally piloted pain severity coding system was used to group participants into 5 discrete ordered pain categories based on their pain persistence (days with pain in the last 3 months) and bothersomeness (little, a lot, somewhere in between): pain free and categories 1 (low) to 4 (high). It is estimated that 126.1 million adults reported some pain in the previous 3 months, with 25.3 million adults (11.2%) suffering from daily (chronic) pain and 23.4 million (10.3%) reporting a lot of pain. Based on the persistence and bothersomeness of their pain, 14.4 million adults (6.4%) were classified as having the highest level of pain, category 4, with an additional 25.4 million adults (11.3%) experiencing category 3 pain. Individuals with category 3 or 4 pain were likely to have worse health status, to use more health care, and to suffer from more disability than those with less severe pain. Associations were seen between pain severity and selected demographic variables including race, ethnicity, preferred language, sex, and age. ⋯ U.S. estimates of pain prevalence are presented using a simple approach for assigning pain severity developed by the Washington Group on Disability Statistics. Concurrent validity is assessed. Although this approach is promising, additional work is required to determine the usefulness of the Washington Group pain categories for pain research or clinical practice.
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Although high levels of negative affect and cognitions have been associated with greater pain sensitivity in chronic pain conditions, the neural mechanisms mediating the hyperalgesic effect of psychological factors in patients with pain disorders are largely unknown. In this cross-sectional study, we hypothesized that 1) catastrophizing modulates brain responses to pain anticipation and 2) anticipatory brain activity mediates the hyperalgesic effect of different levels of catastrophizing in fibromyalgia (FM) patients. Using functional magnetic resonance imaging, we scanned the brains of 31 FM patients exposed to visual cues anticipating the onset of moderately intense deep-tissue pain stimuli. Our results indicated the existence of a negative association between catastrophizing and pain-anticipatory brain activity, including in the right lateral prefrontal cortex. A bootstrapped mediation analysis revealed that pain-anticipatory activity in the lateral prefrontal cortex mediates the association between catastrophizing and pain sensitivity. These findings highlight the role of the lateral prefrontal cortex in the pathophysiology of FM-related hyperalgesia and suggest that deficits in the recruitment of pain-inhibitory brain circuitry during pain-anticipatory periods may play an important contributory role in the association between various degrees of widespread hyperalgesia in FM and levels of catastrophizing, a well-validated measure of negative cognitions and psychological distress. ⋯ This article highlights the presence of alterations in pain-anticipatory brain activity in FM. These findings provide the rationale for the development of psychological or neurofeedback-based techniques aimed at modifying patients' negative affect and cognitions toward pain.
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Omega-3 and omega-6 fatty acids are biosynthetic precursors of endocannabinoids with antinociceptive, anxiolytic, and neurogenic properties. We recently reported that targeted dietary manipulation-increasing omega-3 fatty acids while reducing omega-6 linoleic acid (the H3-L6 intervention)-reduced headache pain and psychological distress among chronic headache patients. It is not yet known whether these clinical improvements were due to changes in endocannabinoids and related mediators derived from omega-3 and omega-6 fatty acids. We therefore used data from this trial (N = 55) to investigate 1) whether the H3-L6 intervention altered omega-3- and omega-6-derived endocannabinoids in plasma and 2) whether diet-induced changes in these bioactive lipids were associated with clinical improvements. The H3-L6 intervention significantly increased the omega-3 docosahexaenoic acid derivatives 2-docosahexaenoylglycerol (+65%, P < .001) and docosahexaenoylethanolamine (+99%, P < .001) and reduced the omega-6 arachidonic acid derivative 2-arachidonoylglycerol (-25%, P = .001). Diet-induced changes in these endocannabinoid derivatives of omega-3 docosahexaenoic acid, but not omega-6 arachidonic acid, correlated with reductions in physical pain and psychological distress. These findings demonstrate that targeted dietary manipulation can alter endocannabinoids derived from omega-3 and omega-6 fatty acids in humans and suggest that 2-docosahexaenoylglycerol and docosahexaenoylethanolamine could have physical and/or psychological pain modulating properties.
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Population-based studies suggest that pain in the lower body is common and that pain at multiple sites is more prevalent than single-site pain. Obesity is a risk factor for multisite musculoskeletal pain, but there are limited data on the role of body composition. Therefore, we sought to determine whether body composition is associated with multisite musculoskeletal pain involving the low back, knee, and foot. A total of 133 participants were recruited for a study examining the relationship between obesity and musculoskeletal disease. Participants completed validated questionnaires that examined levels of pain at the low back, knee, and foot. Body composition was assessed using dual-energy x-ray absorptiometry. Multisite pain was common, with 26.3% of participants reporting pain at 2 sites and 31.6% at 3 sites, and only 20% were pain free. The low back was the most common site of pain (63%). Greater fat mass and fat mass index, but not fat-free mass, were associated with pain at a greater number of sites, independent of age, gender, and fat-free mass (P < .01). Longitudinal studies exploring the mechanism of action by which increased fat mass is associated with pain may provide important insights into therapeutic strategies for the prevention of multisite pain. ⋯ Greater fat mass and fat mass index were associated with a greater number of lower body pain sites, with no association observed for fat-free mass. Understanding the mechanism by which increased fat mass is associated with pain may provide important insights into therapeutic strategies for the prevention of pain.
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Fibromyalgia syndrome (FMS) is characterized by widespread chronic pain, fatigue, sleep disorders, and cognitive-emotional disturbance. Patients with FMS exhibit increased sensitivity to experimental pain and pain-related cues, as well as deficits in emotional regulation. The present study investigated the spatiotemporal patterns of brain activations for observed pain in 19 patients with FMS and 18 age-matched, healthy control individuals using event-related potential analysis. Patients with FMS attributed greater pain and unpleasantness to pain pictures, relative to healthy control participants. An augmented late positive potential (LPP) component (>500 milliseconds) was found in patients viewing both pain and nonpain pictures, and this amplitude difference in the LPP covaried with perceived unpleasantness of pictures. Mid-latency potentials (250-450 milliseconds) demonstrated similar amplitude increases of positive potentials in the FMS patient group. By contrast, the short-latency positive potential (140 milliseconds) was reduced in patients with FMS relative to healthy control participants. Results suggest amplitude increases to mid- to long-latency cortical activations in patients with FMS, which are known to reflect emotional control and motivational salience of stimuli. ⋯ Patients with FMS demonstrate increased activations associated with pain and nonpain pictures. The findings suggest that even innocuous, everyday visual stimuli with somatic connotations may challenge the emotional state of patients with FMS. Our study points toward the importance of cognitive-emotional therapeutic approaches for the treatment of FMS.