Pain
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A child maltreatment history is reported more frequently among adults with chronic pain compared with the general population; unfortunately, studies have primarily relied upon retrospective maltreatment reports by adults with chronic pain. This prospective study assessed pain symptoms in a cohort of young adult women with a documented history of child maltreatment, compared with a matched cohort of women who did not experience childhood maltreatment. Young women (N = 477) were recruited between ages 14 to 17 years and followed annually to age 19. ⋯ As adults, women who had experienced child maltreatment reported higher pain intensity, a greater number of pain locations, and were more likely to experience pain in the previous week than nonmaltreated women. Adolescent post-traumatic stress partially explained the effects of maltreatment on pain. Young adult women who experienced child maltreatment are at higher risk of pain, particularly when they also experienced post-traumatic stress as adolescents.
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The investigation of neurotransmitter systems in placebo and nocebo effects has improved our understanding of these phenomena. Yet, most studies involve healthy participants. Because the pain modulatory system may differ in healthy participants and patients with chronic pain, it is important to investigate the evidence for neurotransmitter involvement in placebo and nocebo effects in each of these populations. ⋯ Overall, research has come a long way in specifying the neurotransmitter systems involved in placebo effects in healthy participants. Yet, evidence for the involvement of neurotransmitter systems in placebo effects in patients with chronic pain and in nocebo effects in healthy participants and patients is scarce. Based on the existing evidence, this systematic review suggests that knowledge obtained in healthy participants may not necessarily be transferred to chronic pain.
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The objective of this study was to examine pain as a predictor of frailty over 18 years of follow-up among older Mexican Americans who were nonfrail at baseline. Data were from a prospective cohort study of 1545 community-dwelling Mexican Americans aged ≥67 years from the Hispanic Established Populations for the Epidemiological Study of the Elderly (1995/1996-2012/2013). Frailty was defined as meeting 2 or more of the following: unintentional weight loss of >10 pounds, weakness, self-reported exhaustion, and slowness. ⋯ Female participants and those with higher levels of education and high Mini-Mental State Examination scores were less at risk. In conclusion, pain was a significantly predictor of frailty. Early assessment and better management of pain may prevent early onset of frailty in older Mexican Americans.
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Brain-derived neurotrophic factor (BDNF) and the high-affinity receptor tropomyosin receptor kinase B (TrkB) have important roles in neuronal survival and in spinal sensitization mechanisms associated with chronic pain. Recent clinical evidence also supports a peripheral role of BDNF in osteoarthritis (OA), with synovial expression of TrkB associated with higher OA pain. The aim of this study was to use clinical samples and animal models to explore the potential contribution of knee joint BDNF/TrkB signalling to chronic OA pain. ⋯ Intra-articular injection of BDNF augmented established OA pain behaviour in MIA rats, but had no effect in controls. Intra-articular injection of the TrkB-Fc chimera acutely reversed pain behaviour to a similar extent in both models of OA pain (weight-bearing asymmetry MIA: -11 ± 4%, MNX: -12 ± 4%), compared to vehicle treatment. Our data suggesting a contribution of peripheral knee joint BDNF/TrkB signalling in the maintenance of chronic OA joint pain support further investigation of the therapeutic potential of this target.
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Recent research has highlighted a need for the psychometric evaluation of instruments targeting core domains of the pain experience in chronic pain populations. In this study, the measurement properties of Short Form-36 Health Survey (SF-36),EuroQol 5-dimensions (EQ-5D) and Hospital Anxiety and Depression Scale (HADS) were analyzed within the item response-theory framework based on data from 35,908 patients. To assess the structural validity of these instruments, the empirical representations of several conceptually substantiated latent structures were compared in a cross-validation procedure. ⋯ In support of convergent and discriminant validity, correlations between questionnaires showed that theoretically similar traits were highly associated, whereas unrelated traits were not. Our models can be applied to score SF-36 and HADS in chronic pain patients, but we recommend against using the EQ-5D model due to its low reliability. These results are useful for researchers and clinicians involved in chronic pain populations because questionnaires' properties determine their discriminating ability in patient status assessment.