A low cortisol response to stress is associated with musculoskeletal pain combined with increased pain sensitivity in young adults: a longitudinal cohort study

The role of nitric oxide and neuroendocrine system in pain generation

Previous studies have indicated a complex interplay between the nitric oxide (NO) pain signaling pathways and hormonal signaling pathways in the body. This article delineates the role of nitric oxide signaling in neuropathic and inflammatory pain generation and subsequently discusses how the neuroendocrine system is involved in pain generation. Hormonal systems including the hypothalamic-pituitary axis (HPA) generation of cortisol, the renin-angiotensin-aldosterone system, calcitonin, melatonin, and sex hormones could potentially contribute to the generation of nitric oxide involved in the sensation of pain. Further research is necessary to clarify this relationship and may reveal therapeutic targets involving NO signaling that alleviate neuropathic and inflammatory pain.

Forced swim stress exacerbates inflammation-induced hyperalgesia and oxidative stress in the rat trigeminal ganglia

This study investigates the impact of combining psychophysical stress, induced by forced swim (FSS), with masseter inflammation on reactive oxygen species (ROS) production in trigeminal ganglia (TG), TRPA1 upregulation in TG, and mechanical hyperalgesia. In a rat model, we demonstrate that FSS potentiates and prolongs CFA-induced ROS upregulation within TG. The ROS levels in CFA combined with FSS group surpass those in the CFA-only group on days 4 and 28 post-treatment. FSS also enhances TRPA1 upregulation in TG, with prolonged expression compared to CFA alone. Furthermore, CFA-induced mechanical hyperalgesia is significantly prolonged by FSS, persisting up to day 28. PCR array analyses reveal distinct alterations in oxidative stress genes under CFA and CFA combined with FSS conditions, suggesting an intricate regulation of ROS within TG. Notably, genes like Nox4, Hba1, Gpx3, and Duox1 exhibit significant changes, providing potential targets for managing oxidative stress and inflammatory pain. Western blot and immunohistochemistry confirm DUOX1 protein upregulation and localization in TG neurons, indicating a role in ROS generation under inflammatory and stress conditions. This study underscores the complex interplay between psychophysical stress, inflammation, and oxidative stress in the trigeminal system, offering insights into novel therapeutic targets for pain management.

Higher self-perceived stress reactivity is associated with increased chronic pain risk

Self-perceived stress reactivity—how a person cognitively and emotionally responds to a stressor—is longitudinally associated with increased odds for the development of chronic pain.

Introduction:

Experiencing stress can contribute to unfavorable pain experiences, but outcomes vary across individuals. Evidence suggests that a person's specific reactivity to stressful events may influence pain responses. Previous studies measuring physiological stress reactivity have found associations with pain both clinically and in the laboratory. However, the time and cost required for testing physiological stress reactivity may limit clinical application.

Objective:

Self-reported perception of one's own stress reactivity has been shown to correlate with physiological stress reactivity in relation to health outcomes and may represent a valuable tool in clinical pain assessment.

Methods:

Using data from the Midlife in the US survey, we selected participants who did not have chronic pain at baseline (n = 1512) and who had data at follow-up 9 years later. Stress reactivity was assessed using a subscale of the Multidimensional Personality Questionnaire. We conducted a binary logistic regression to determine the odds of developing chronic pain, controlling for demographics and other health-related variables.

Results:

Results indicate that higher reported stress reactivity at baseline increased the odds of developing chronic pain at follow-up (odds ratio (OR) = 1.085, 95% confidence interval (CI) (1.021, 1.153), P = 0.008), with the only other significant predictor being the number of chronic conditions (OR = 1.118, 95% CI (1.045, 1.197), P = 0.001).

Conclusion:

Findings provide evidence for the predictive criterion validity of self-reported stress reactivity in the context of chronic pain risk. More generally, with increased need for virtual assessment and care, self-reported stress reactivity may be a useful, time-efficient, and cost-efficient tool for predicting pain outcomes in research and clinical contexts.

The Biology of Stress Intolerance in Patients with Chronic Pain—State of the Art and Future Directions

Stress has been consistently linked to negative impacts on physical and mental health. More specifically, patients with chronic pain experience stress intolerance, which is an exacerbation or occurrence of symptoms in response to any type of stress. The pathophysiological mechanisms underlying this phenomenon remain unsolved. In this state-of-the-art paper, we summarised the role of the autonomic nervous system (ANS) and hypothalamus-pituitary-adrenal (HPA) axis, the two major stress response systems in stress intolerance. We provided insights into such mechanisms based on evidence from clinical studies in both patients with chronic pain, showing dysregulated stress systems, and healthy controls supported by preclinical studies, highlighting the link between these systems and symptoms of stress intolerance. Furthermore, we explored the possible regulating role for (epi)genetic mechanisms influencing the ANS and HPA axis. The link between stress and chronic pain has become an important area of research as it has the potential to inform the development of interventions to improve the quality of life for individuals living with chronic pain. As stress has become a prevalent concern in modern society, understanding the connection between stress, HPA axis, ANS, and chronic health conditions such as chronic pain is crucial to improve public health and well-being.

Blunted cardiovascular reactivity to psychological stress and prospective health: a systematic review

Novel research demonstrates that lower or 'blunted' cardiovascular reactions to stress are associated with a range of adverse outcomes. The aim of the current review was (1) to examine the prospective outcomes predicted by blunted cardiovascular reactivity and (2) to identify a range of blunted cardiovascular reaction levels that predict these outcomes. Electronic databases were systematically searched (Medline, PsycArticles, PsycInfo, CINAHL, PubMed, Web of Science). Studies were included if they examined the prospective influence of blunted cardiovascular reactivity to psychological stress (SBP, DBP or HR) on a negative health, behavioural or psychological outcome. A total of 23 studies were included in the review. Blunted reactivity predicted (1) adverse cardiovascular health, primarily in cardiac samples (e.g., myocardial infarction, carotid atherosclerosis) and (2) outcomes associated with motivational and behavioural dysregulation in healthy samples (e.g., obesity, smoking addiction, depression). The cardiovascular reactivity threshold levels that were predictive of adverse health outcomes ranged between -3.00-12.59 bpm (14.41% to 136.59% lower than the sample mean) and -2.4-5.00 mmhg (65.99% to 133.80% lower than sample mean), for HR and DBP respectively. We posit that blunted reactions lower than, or equal to, the ranges reported here may be utilised by clinicians and researchers to identify individuals who are at increased risk of adverse cardiovascular health outcomes, as well as outcomes associated with motivational and behavioural dysregulation.

Sex differences in factors associated with neck pain among undergraduate healthcare students: a cross-sectional survey

Background

Neck pain is widespread among students in healthcare-related fields. Although neck pain is more prevalent in females, since most research involves mixed-sex samples we know very little about sex differences in contributors to neck pain. Thus, this study sought to explore sex differences in the risk factors for neck pain in this high-risk population.

Methods

This cross-sectional study was conducted in China in 2021 and included a sample of 1921 undergraduate healthcare students (693 males, 1228 females) from 7 health professional schools at Fujian Medical University. We collected data on neck pain symptoms, demographics, behavioral and psychological factors. Multiple regression analysis was conducted to examine sex differences in the risk factors of neck pain.

Results

The overall prevalence of neck pain was 41.6% with female students having a higher prevalence than male students (44.4% vs. 36.7%, respectively). The adjusted analyses showed that self-study time ≥ 6 h/day (OR = 1.44, 95% CI:1.13-1.83), flexed neck posture >20 degrees (OR = 2.19, 95% CI: 1.28-3.74), static duration posture >2 h (OR = 1.42, 95% CI: 1.02-1.97), and psychological distress (high: OR = 2.04, 95% CI:1.42-2.94; very high: OR = 2.50, 95% CI:1.57-3.74; respectively) were independent factors for neck pain in females. Among males, self-study time ≥ 6 h/day (OR = 1.43, 95% CI: 1.02-2.01) and psychological distress (moderate: OR = 2.04, 95% CI:1.28-3.25; high: OR = 2.37, 95% CI:1.49-3.79; very high: OR = 2.97, 95% CI:1.75-5.02; respectively) were significant risk factors for neck pain.

Conclusions

These findings suggest that the risk profiles of neck pain differ between females and males. The modifiable risk factors for neck pain, such as prolonged self-study time and elevated psychological distress, as well as poor posture among females, could be targeted through health promotion interventions in university settings.

Serum Concentrations of the Endocannabinoid, 2-Arachidonoylglycerol, in the Peri-Trauma Period Are Positively Associated with Chronic Pain Months Later

Endocannabinoid signaling and the hypothalamic-pituitary-adrenal axis are activated by trauma and both stress systems regulate the transition from acute to chronic pain. This study aimed to develop a model of relationships among circulating concentrations of cortisol and endocannabinoids (eCBs) immediately after traumatic injury and the presence of chronic pain months later. Pain scores and serum concentrations of eCBs and cortisol were measured during hospitalization and 5–10 months later in 147 traumatically injured individuals. Exploratory correlational analyses and path analysis were completed. The study sample was 50% Black and Latino and primarily male (69%); 34% percent endorsed a pain score of 4 or greater at follow-up and were considered to have chronic pain. Path analysis was used to model relationships among eCB, 2-arachidonolyglycerol (2-AG), cortisol, and pain, adjusting for sex and injury severity (ISS). Serum 2-AG concentrations at the time of injury were associated with chronic pain in 3 ways: a highly significant, independent positive predictor; a mediator of the effect of ISS, and through a positive relationship with cortisol concentrations. These data indicate that 2-AG concentrations at the time of an injury are positively associated with chronic pain and suggest excessive activation of endocannabinoid signaling contributes to risk for chronic pain.

The relationship between chronotypes and musculoskeletal problems in male automobile manufacturing workers

Background

Previous studies have shown that morning types are less sensitive to pain. This study aimed to examine the relationship between chronotypes and musculoskeletal problems in workers with musculoskeletal burdens at work.

Methods

This cross-sectional study included 119 male production workers from a large automobile manufacturing plant. All the participants worked 2 shifts and worked on the automobile assembly line. Data were obtained using structured questionnaires, including the reduced Morningness-Eveningness Questionnaire (rMEQ), and musculoskeletal symptom questionnaire. Participants with an rMEQ score of 18 points or more were defined as morning-type workers (MTWs). Participants whose scores were less than 18 points were defined as neither-type workers (NTWs).

Results

The arithmetic mean age was 51.8 ± 5.3 years. MTWs and NTWs accounted for 35.3% and 64.7% of the total participants, respectively. Evening- and intermediate-type workers accounted form 6.7% and 58.0% of the participants, respectively. There was no significant difference in the health indicators when the MTW and NTW groups were compared. However, the musculoskeletal symptom questionnaire demonstrated a significant difference between the MTW and NTW groups. In the preceding year, the MTW group had significantly lower musculoskeletal pain and treatment ratios compared to the NTW group (35.7% vs. 62.3%, p = 0.005 and 14.3% vs. 32.5%, p = 0.031, respectively). After adjusting for variables, the odds ratio (OR) for musculoskeletal pain was significantly higher in the NTW group than in the MTW group (OR, 3.112; 95% confidence interval, 1.285–7.535; p = 0.012).

Conclusions

In this study, the musculoskeletal pain ratio was significantly lower for MTWs when compared to NTWs. Chronotypes could play an important role in work-related musculoskeletal disorders. Further, larger-scale, follow-up studies on chronotypes are required to assist in the prevention of musculoskeletal disorders in future.

Caring for the psychosocial needs of the acutely traumatized patient

ABSTRACT

Support for a patient in the aftermath of a potentially traumatic event is enhanced when clinicians understand the normal reactions that may occur during the traumatization process. This article discusses recommendations from international and national guidelines as well as best practices from the medical and psychiatric literature to help guide clinicians providing care for acutely traumatized patients.

Heritability of musculoskeletal pain and pain sensitivity phenotypes: two generations of the Raine Study

ABSTRACT

There is a need to better understand biological factors that increase the risk of persistent musculoskeletal pain and heightened pain sensitivity. Knowing the heritability (how genes account for differences in people's traits) can enhance the understanding of genetic versus environmental influences of pain and pain sensitivity. However, there are gaps in current knowledge, including the need for intergenerational studies to broaden our understanding of the genetic basis of pain. Data from Gen1 and Gen2 of the Raine Study were used to investigate the heritability of musculoskeletal pain, and pressure and cold pain sensitivity. Participants included parents (Gen 1, n=1092) and their offspring (Gen 2, n=688) who underwent a battery of testing and questionnaires including pressure and cold pain threshold testing and assessments of physical activity, sleep, musculoskeletal pain, mental health and adiposity. Heritability estimates were derived using the Sequential Oliogenic Linkage Analysis Routines (SOLAR) software. Heritability estimates for musculoskeletal pain and pressure pain sensitivity were significant, accounting for between 0.190 and 0.289 of the variation in the phenotype. In contrast, heritability of cold pain sensitivity was not significant. This is the largest intergenerational study to date to comprehensively investigate the heritability of both musculoskeletal pain and pain sensitivity, using robust statistical analysis. This study provides support for the heritability of musculoskeletal pain and pain sensitivity to pressure, suggesting the need for further convergence of genetic and environmental factors in models for the development and/or maintenance of these pain disorders.

Usual presence and intensity of pain are differentially associated with suicidality across chronic pain conditions: A population-based study

OBJECTIVES

This study examined the prevalence of suicidality and associations with pain characteristics (i.e., presence of usual pain/discomfort, pain intensity) among those with chronic pain conditions (i.e., arthritis, migraine, back pain).

METHODS

We analyzed data from the 2012 Canadian Community Health Survey-Mental Health supplement (N = 25,113), including self-reported pain characteristics and suicidality. Weighted cross-tabulations described suicidality prevalence estimates according to pain characteristics among each chronic pain condition. Multiple logistic regressions evaluated associations between the presence of usual pain/discomfort and suicidality across pain conditions. Post-hoc analyses examined pain intensity in significant associations.

RESULTS

Across pain conditions, rates of suicidality were greater in those usually in pain and with more severe pain, compared to mild or moderate pain. After adjustment, usual pain/discomfort was associated with increased odds of suicide ideation (AOR = 1.79, 95% CI [1.19-2.68], p < .05) and attempts (AOR = 2.49, 95% CI [1.25-4.98], p < .05) among those with migraines, and plans (AOR = 1.55, 95% CI [1.04-2.31], p < .05) in those with back pain (reference = absence of usual pain). Usual pain/discomfort was not associated with suicidality in those with arthritis after adjusting for sociodemographics and psychiatric comorbidity. Post-hoc analyses showed that severe pain was associated with elevated odds of suicide ideation (AOR = 2.19, 95% CI [1.07-4.48], p < .05) in migraines and plans (AOR = 3.11, 95% CI [1.42-6.80], p < .01) in back pain (reference = mild pain).

CONCLUSION

Our findings may facilitate a more targeted approach to screening for suicidality among chronic pain populations.

Morning and evening salivary cortisol levels in patients with chronic widespread pain and those at high risk

BACKGROUND

Hypothalamic-Pituitary-Adrenal (HPA) axis dysregulation has been implicated in chronic widespread pain (CWP); the hallmark of fibromyalgia (FM). This is the first study to compare HPA axis changes in individuals with CWP and those at high risk of symptom development.

METHODS

We sought to determine differences in morning and evening salivary cortisol levels in FM (n = 19), those at-risk (n = 20) and pain-free controls (n = 17). Risk factors included non-CWP pain, somatic symptoms, illness behaviour and sleep disturbance. We conducted the study in the absence of centrally acting medication, to address limitations of previous research.

RESULTS

Repeated measures ANOVA revealed significant main effects of group (p = 0.003), and time of day (p = 0.002), with no significant interaction. Cortisol levels were higher in FM (p = 0.027) and at-risk (p = 0.003) groups, compared to controls, but there was no significant difference between FM and at-risk groups. The main effect of group remained significant with sleep problems (p = 0.021) and life events (p = 0.007), but was not significant with anxiety (p = 0.076) or depression (p = 0.098) scores as covariates. With sleep problems as a covariate, cortisol levels remained significantly higher only in the at-risk group (p = 0.017).

CONCLUSIONS

This study indicates elevated salivary cortisol in FM and those at high risk, and identifies anxiety, depression and sleep problems as potential contributing factors. The results shed light on the dynamic relationship between stress, mood and sleep disorders and the brain's resilience to pain.

SIGNIFICANCE

This study examines neurobiological changes in chronic widespread pain and high risk individuals. One strength of the study is the absence of centrally acting medication. We found high salivary cortisol common to Fibromyalgia and those at risk and identified contributing factors. Our results offer insight into the early mechanistic changes underlying Fibromyalgia development and open up possibilities for early diagnosis and prevention.

Is Neck Posture Subgroup in Late Adolescence a Risk Factor for Persistent Neck Pain in Young Adults? A Prospective Study

OBJECTIVE

The purpose of this study was to determine whether sagittal neck sitting posture subgroup membership in late adolescence was a risk factor for persistent neck pain (PNP) in young adults.

METHODS

There were 686 participants enrolled in the Raine Study at the 17- and 22-year follow-ups. At 17 years of age, posture was measured by photographs, and 4 subgroups of sitting neck posture were determined by cluster analysis. Height and weight were measured, and exercise frequency, depression, and PNP were assessed by questionnaire. At 22 years of age, participants answered questions about neck pain and occupation type. Logistic regression examined if neck posture subgroups at 17 years of age were a risk factor for PNP at 22 years of age, taking into account other factors.

RESULTS

Female sex (odds ratio [OR] = 1.75, 95% CI = 1.16-2.65) and PNP at 17 years of age (OR = 3.78, 95% CI = 2.57-5.57) were associated with PNP at 22 years of age. In females, neck posture subgroup at 17 years of age was a risk factor for PNP at 22 years of age. Compared with the upright subgroup, both the slumped thorax/forward head subgroup groups and the intermediate subgroup had decreased odds for PNP at 22 years of age (OR = 0.24, 95% CI = 0.08-0.76; OR = 0.38, 95% CI = 0.15-0.99, respectively). No association was found in males.

CONCLUSION

After taking into account PNP at 17 years, sitting neck posture at 17 was not a risk factor for PNP at 22 years of age in males, whereas in females, more relaxed postures (slumped thorax/forward head and Intermediate postures) were protective of neck pain compared with upright posture.

IMPACT

Females in late adolescence who sat in slumped thorax/forward head or intermediate posture rather than upright sitting posture had a lower risk of PNP as a young adult. The practice of generic public health messages to sit up straight to prevent neck pain needs rethinking.

Psychological stress reactivity and future health and disease outcomes: A systematic review of prospective evidence

BACKGROUND

Acute psychological stress activates the sympatho-adrenal medullary (SAM) system and hypothalamo-pituitary adrenal (HPA) axis. The relevance of this stress reactivity to long-term health and disease outcomes is of great importance. We examined prospective studies in apparently healthy adults to test the hypothesis that the magnitude of the response to acute psychological stress in healthy adults is related to future health and disease outcomes.

METHODS

We searched Medline Complete, PsycINFO, CINAHL Complete and Embase up to 15 Aug 2019. Included studies were peer-reviewed, English-language, prospective studies in apparently healthy adults. The exposure was acute psychological stress reactivity (SAM system or HPA axis) at baseline. The outcome was any health or disease outcome at follow-up after ≥1 year.

RESULTS

We identified 1719 papers through database searching and 1 additional paper through other sources. Forty-seven papers met our criteria including 32,866 participants (range 30-4100) with 1-23 years of follow-up. Overall, one third (32 %; 83/263) of all reported findings were significant and two thirds (68 %; 180/263) were null. With regard to the significant findings, both exaggerated (i.e. high) and blunted (i.e. low) stress reactivity of both the SAM system and the HPA axis at baseline were related to health and disease outcomes at follow-up. Exaggerated stress reactivity at baseline predicted an increase in risk factors for cardiovascular disease and decreased telomere length at follow-up. In contrast, blunted stress reactivity predicted future increased adiposity and obesity, more depression, anxiety and PTSD symptoms, greater illness frequency, musculoskeletal pain and regulatory T-Cell percentage, poorer cognitive ability, poorer self-reported health and physical disability and lower bone mass.

CONCLUSION

Exaggerated and blunted SAM system and HPA axis stress reactivity predicted distinct physical and mental health and disease outcomes over time. Results from prospective studies consistently indicate stress reactivity as a predictor for future health and disease outcomes. Dysregulation of stress reactivity may represent a mechanism by which psychological stress contributes to the development of future health and disease outcomes.

Walking the Tightrope: A Proposed Model of Chronic Pain and Stress

Pain and stress are both phenomena that challenge an individual’s homeostasis and have significant overlap in conceptual and physiological processes. Allostasis is the ability to adapt to pain and stress and maintain homeostasis; however, if either process becomes chronic, it may result in negative long-term outcomes. The negative effects of stress on health outcomes on physiology and behavior, including pain, have been well documented; however, the specific mechanisms of how stress and what quantity of stress contributes to the maintenance and exacerbation of pain have not been identified, and thus pharmacological interventions are lacking. The objective of this brief review is to: 1. identify the gaps in the literature on the impact of acute and chronic stress on chronic pain, 2. highlight future directions for stress and chronic pain research; and 3. introduce the Pain-Stress Model in the context of the current literature on stress and chronic pain. A better understanding of the connection between stress and chronic pain could provide greater insight into the neurobiology of these processes and contribute to individualized treatment for pain rehabilitation and drug development for these often comorbid conditions.

Transitioning from acute to chronic pain: a simulation study of trajectories of low back pain

Background

Identifying how pain transitions from acute to chronic is critical in designing effective prevention and management techniques for patients’ well-being, physically, psychosocially, and financially. There is an increasingly pressing need for a quantitative and predictive method to evaluate how low back pain trajectories are classified and, subsequently, how we can more effectively intervene during these progression stages.

Methods

In order to better understand pain mechanisms, we investigated, using computational modeling, how best to describe pain trajectories by developing a platform by which we studied the transition of acute chronic pain.

Results

The present study uses a computational neuroscience-based method to conduct such trajectory research, motivated by the use of hypothalamic–pituitary–adrenal (HPA) axis activity-history over a time-period as a way to mimic pain trajectories. A numerical simulation study is presented as a “proof of concept” for this modeling approach.

Conclusions

This model and its simulation results have highlighted the feasibility and the potential of developing such a broader model for patient evaluations.

The Effects Induced by Spinal Manipulative Therapy on the Immune and Endocrine Systems

Background and Objectives: Spinal manipulations are interventions widely used by different healthcare professionals for the management of musculoskeletal (MSK) disorders. While previous theoretical principles focused predominantly on biomechanical accounts, recent models propose that the observed pain modulatory effects of this form of manual therapy may be the result of more complex mechanisms. It has been suggested that other phenomena like neurophysiological responses and the activation of the immune-endocrine system may explain variability in pain inhibition after the administration of spinal manipulative therapy (SMT). The aim of this paper is to provide an overview of the available evidence supporting the biological plausibility of high-velocity, low-amplitude thrust (HVLAT) on the immune-endocrine system. Materials and Methods: Narrative critical review. An electronic search on MEDLINE, ProQUEST, and Google Scholar followed by a hand and "snowballing" search were conducted to find relevant articles. Studies were included if they evaluated the effects of HVLAT on participants' biomarkers Results: The electronic search retrieved 13 relevant articles and two themes of discussion were developed. Nine studies investigated the effects of SMT on cortisol levels and five of them were conducted on symptomatic populations. Four studies examined the effects of SMT on the immune system and all of them were conducted on healthy individuals. Conclusions: Although spinal manipulations seem to trigger the activation of the neuroimmunoendocrine system, the evidence supporting a biological account for the application of HVLAT in clinical practice is mixed and conflicting. Further research on subjects with spinal MSK conditions with larger sample sizes are needed to obtain more insights about the biological effects of spinal manipulative therapy.

Associations of physical activity or sedentary behaviour with pain sensitivity in young adults of the Raine Study

Background and aims

There is high level evidence for physical activity (PA) improving outcomes in persistent pain disorders and one of the mechanisms proposed is the effect of exercise on central nociceptive modulation. Although laboratory studies and small field intervention studies suggest associations between physical activity and pain sensitivity, the association of objectively measured, habitual PA and sedentary behaviour (SB) with pain sensitivity requires further investigation. Current evidence suggests PA typically lowers pain sensitivity in people without pain or with single-site pain, whereas PA is frequently associated with an increase in pain sensitivity for those with multisite pain. The aim of this study was to explore the relationships of PA and SB with pain sensitivity measured by pressure pain thresholds and cold pain thresholds, considering the presence of single-site and multisite pain and controlling for potential confounders.

Methods

Participants from the Western Australian Pregnancy Cohort (Raine) Study (n = 714) provided data at age 22-years. PA and SB were measured via accelerometry over a 7-day period. Pain sensitivity was measured using pressure pain threshold (4 sites) and cold pain threshold (wrist). Participants were grouped by number of pain areas into “No pain areas” (n = 438), “Single-site pain” (n = 113) and “Multisite pain” (n = 163) groups. The association of PA and SB variables with pain sensitivity was tested separately within each pain group by multivariable regression, adjusting for potential confounders.

Results

For those with “Single-site pain”, higher levels (>13 min/day) of moderate-vigorous PA in ≥10 min bouts was associated with more pressure pain sensitivity (p = 0.035). Those with “Multisite pain” displayed increased cold pain sensitivity with greater amounts of vigorous PA (p = 0.011). Those with “No pain areas” displayed increased cold pain sensitivity with decreasing breaks from sedentary time (p = 0.046).

Conclusions

This study was a comprehensive investigation of a community-based sample of young adults with “No pain areas”, “Single-site pain” and “Multisite pain” and suggests some associations of measures of PA and SB with pain sensitivity.

Implications

The findings suggest that the pattern of accumulation of PA and SB may be important to inform improved clinical management of musculoskeletal pain disorders. This study provides a baseline for follow-up studies using the Raine Study cohort. Future research should consider temporal influences of PA and SB on pain sensitivity, pain experience and consider using a broader range of pain sensitivity measures.

Is There Support for the Paradigm 'Spinal Posture as a Trigger for Episodic Headache'? A Comprehensive Review

PURPOSE OF REVIEW

The International Classification of Headache Disorders provides an extensive framework to classify headaches. Physiotherapy is indicated if neuromusculoskeletal dysfunctions are involved in the pathophysiology. Maladaptive postures seem a dominant trigger in tension-type and cervicogenic headache. Yet, outcomes following physiotherapy vary. The absence of protocol studies to identify determinants concerning the role of spinal posture in headache might explain such variability. Hence, multi-dimensional profiling of patients with headache based on interactions between spinal posture, psychosocial and lifestyle factors might be essential. Therefore, the aim of this paper was to perform a comprehensive review to find support for the paradigm of spinal posture triggering episodic headache based on a multi-dimensional view on tension-type and cervicogenic headache including modern pain neuroscience.

RECENT FINDINGS

A review was conducted to support spinal posture-induced episodic headache. Pubmed, Web of Science, Pedro and the Cochrane database were explored based on the following 'Mesh' or 'Topics': 'Headache', 'Posture', 'Spine', 'Psychosocial', 'Lifestyle'. The contemporary review of neuroanatomical, biomechanical and non-nociceptive pathways, with integration of modern pain neuroscience in tension-type and cervicogenic headache, supports spinal posture as a trigger for episodic headache. Maladaptive postures can activate C1-C3 nociceptors. Convergence with trigeminal afferents at the trigeminocervical nucleus could explain spinal headache. Interactions with psychosocial and lifestyle factors might contribute to peripheral and central sensitisation. Neuroanatomical, biomechanical and non-nociceptive pathways seem to justify profiling patients based on a postural trigger. Further research is needed to determine the contribution of postural dysfunctions in headache and the effect of specific interventions.

Hypothalamic-pituitary-adrenal axis feedback sensitivity in different states of back pain

Pain normally signals a threat to bodily integrity and causes emotional distress. Acute pain serves a protective function, yet, when pain turns chronic, the protective function is lost. A chain of psychophysiological alterations including changes in the stress regulation system, apparent in dysfunctional activity and responsivity of the hypothalamic-pituitary-adrenal (HPA) axis, might be an important factor in this context. Moreover, maladaptive responses may be complicated by affective comorbid symptoms such as anxiety and depression, and alter nociceptive processing. However, the relationship among pain chronicity, stress regulation, and contributing components of comorbid symptomatology as well as somatosensory profiles has rarely been examined. In the present study, we obtained diurnal cortisol profiles at baseline and feedback regulation (following a dexamethasone suppression test (DST)) in subacute (SABP) and chronic (CBP) back pain patients and healthy control individuals (HC). We also assessed anxiety, depression and chronic stress levels and used quantitative sensory testing (QST) to detect sensory abnormalities. We found a hyper-suppression of cortisol following DST and thus enhanced negative stress feedback sensitivity in SABP compared to both CBP and HC. In SABP, DST-related cortisol levels were negatively associated with pain intensity, mediated by cold pain thresholds and anxiety. These data support a stress model of pain chronicity and suggest that stress responses might be indicators of individual vulnerability in the transition period of subacute pain.

Association between cortisol levels and pain threshold in systemic sclerosis and major depression

Pain perception and threshold show complex interactions with the inflammatory, psychiatric and neuroendocrine stimuli. This study aims to test whether lower serum cortisol levels are associated with lower pain thresholds and higher degree of depression in systemic sclerosis (SSc) and major depression with atypical features (MD-AF) patients compared to controls. 180 female subjects (SSc = 60, MD-AF = 60, healthy controls = 60) participated in this observational, cross-sectional, parallel group study. Pressure pain threshold (PPT) was assessed in three anatomical sites: nail bed (NB), metacarpophalangeal joint (MCP) and quadriceps muscle (QDR). Depressive symptoms were evaluated using the Beck Depression Inventory (BDI) scale and morning serum cortisol levels were collected. In SSc patients, quality of life was measured through the Health Assessment Questionnaire (HAQ-DI) and the scleroderma-specific visual analogue scales (scleroderma-VAS). Lower PPT scores (NB 4.42 ± 1.6; MCP 4.66 ± 1.4; QDR 4.79 ± 1.5) were observed in SSc patients compared to both MD-AF (NB 7.33 ± 2.2; MCP 6.01 ± 1.9; QDR 6.31 ± 1.6; p < 0.005) and controls (NB 9.57 ± 2; MCP 7.9 ± 2.1 and QDR 8.43 ± 2.1; p < 0.0001), while MD-AF patients had lower PPT scores compared to controls (p < 0.0001). SSc patients had also lower serum cortisol levels compared to MD-AF patients (8.78 vs 13.6 μg/dl; p < 0.05). A direct correlation was observed between serum cortisol and PPT scores both in SSc (r ² for NB 0.29; for MCP 0.25; for QDR 0.27) and in MD-AF (r ² for NB 0.34; for MCP 0.25; for QDR 0.47; p < 0.05), while depressive symptoms negatively correlated with serum cortisol (r ² for NB 0.34; for MCP 0.17; for QDR 0.15) and in MD-AF (r ² for NB 0.19; for MCP 0.31; for QDR 0.30; p < 0.05). Among SSc patients, those with serum cortisol levels below the normal range (n = 16) had higher BDI scores (15, 6-21 vs 9, 2-15; p < 0.005), lower PPTs (NB 4 ± 1.4 vs 4.9 ± 0.9; MCP 4.1 ± 0.8 vs 4.8 ± 0.9; QDR 4.1 ± 1.2 vs 5 ± 0.9; p < 0.005) and higher HAQ-DI (1.25, 0.25-2 vs 0.75, 0-1.25; p < 0.05) and scleroderma-VAS scores (VAS overall severity 7, 5.5-9.5 vs 4.5, 2.5-6; p < 0.05). The effect of cortisol serum levels upon pain mechanism, in chronic inflammatory conditions warrants longitudinal studies to detect treatable variations in pain thresholds, depressive symptoms and to improve quality of life.

Understanding Adolescent Low Back Pain From a Multidimensional Perspective: Implications for Management

Synopsis Low back pain (LBP) is the leading cause of disability worldwide. It often begins in adolescence, setting a course for later in life. We have tracked the course of LBP in the Raine Study cohort from the age of 14 years into early adulthood. Our work has found that LBP is already prevalent in individuals at 14 years of age and increases throughout adolescence and into early adulthood. It is often comorbid with other musculoskeletal pain. For some adolescents, LBP has little impact; for others, its impact includes care seeking, taking medication, taking time off from school and work, as well as modifying physical and functional activity. Of concern is the increasing prevalence of LBP with impact across adolescence, reaching adult rates by 22 years of age. The predictors of disabling LBP in adolescence are multidimensional. They include female sex, negative back pain beliefs, poor mental health status, somatic complaints, involvement in sports, and altered stress responses. Genetics also plays a role. Ironically, the factors that we have historically thought to be important predictors of LBP, such as "poor" spinal posture, scoliosis, carrying school bags, joint hypermobility, and poor back muscle endurance, are not strong predictors. This challenges our clinical beliefs and highlights that adolescent LBP needs a flexible and targeted multidimensional approach to assessment and management. In most cases, we recommend a cognitive functional approach that challenges negative LBP beliefs, educates adolescents regarding factors associated with their LBP, restores functional capacity where it is impaired, and encourages healthy lifestyle habits. J Orthop Sports Phys Ther 2017;47(10):741-751. Epub 12 Sep 2017. doi:10.2519/jospt.2017.7376.

Perinatal Depression, Adverse Life Events, and Hypothalamic-Adrenal-Pituitary Axis Response to Cold Pressor Stress in Latinas: An Exploratory Study

BACKGROUND

Latinas are disproportionately affected by perinatal depression (PND) as well as by adverse life events (ALEs), an independent predictor of PND. Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis has been seen both in women with PND and with a history of ALEs in non-Latinas. Although some evidence suggests that HPA axis dysregulation may mediate the link between ALEs and PND, this hypothesis has received little attention and there are no studies that have examined these pathways in Latinas. The primary aim of the present study was to explore, in a Latina sample, associations between ALEs, PND, and HPA axis stress reactivity to a physical stressor, the cold pressor test (CPT). The secondary aim was to explore whether HPA axis reactivity and PND were associated with pain sensitivity to the CPT.

METHODS

Thirty-four Latinas were enrolled in their third trimester of pregnancy and interviewed at 4 and 8 weeks postpartum. Depression status was determined using the Edinburgh Postnatal Depression Scale (≥10). At 8 weeks postpartum, 27 women underwent laboratory-induced pain testing using the CPT. Plasma adrenocorticotropic hormone and cortisol were sampled before and after the CPT to generate a stress reactivity score (post-pre). Pain sensitivity and ALEs were also assessed.

RESULTS

At enrollment, 26% of women were depressed, and 18% were depressed at 8 weeks postpartum. Fifty-two percent reported at least one childhood ALE. There was a significant and positive association between any childhood ALE and prenatal depression scores (p = .025). Infant-related ALEs were significantly associated with greater adrenocorticotropic hormone reactivity to the CPT (p = .030). Women with a history of any childhood ALE exhibited a blunted cortisol response to the CPT (p = .045). Women with a history of PND at 4 weeks had greater adrenocorticotropic hormone stress reactivity to the CPT (p = .027). No effects of PND were seen for pain sensitivity measures in response to the CPT, although there was a positive and significant correlation between pain tolerance and cortisol response to the CPT in the whole sample.

CONCLUSIONS

Given the associations between ALEs and PND and their individual effect on HPA axis stress reactivity, future studies on PND should include a larger sample of Latinas to test the mediating effects of HPA axis reactivity on associations between ALEs and PND.

An Integrated Model of Chronic Whiplash-Associated Disorder

Synopsis The development of persistent symptoms following whiplash injury from a motor vehicle collision is common and contributes substantially to societal and personal costs. The popular Quebec Task Force classification system of whiplash-associated disorders (WADs) was meant to function as a prognostic and intervention decision aid, but its usefulness has been questioned. Emerging evidence highlights the heterogeneity of WAD by demonstrating physical and psychological impairments that are unique to those who develop persistent symptoms. These impairments are not recognized in the Quebec Task Force classification system. The purpose of this clinical commentary is to describe an integrated model that focuses on how psychological and neurobiological factors interact with, and are influenced by, existing personal and environmental factors to contribute to the development of chronic WAD. The model has been developed through more than 20 years of work in the field, consultation with experts, in-depth synthesis of existing evidence, and new evidence from the authors' own research programs. A subtheme is that a point of convergence currently exists between the psychological, physiological, and social determinants of health literature that can further explain the complex presentation of WAD. The new model is proposed to orient future research toward more interdisciplinary efforts across nontraditional fields, including data scientists and consumers, to clarify the WAD condition. J Orthop Sports Phys Ther 2017;47(7):462-471. Epub 16 Jun 2017. doi:10.2519/jospt.2017.7455.

Lifetime Modulation of the Pain System via Neuroimmune and Neuroendocrine Interactions

Chronic pain is a debilitating condition that still is challenging both clinicians and researchers. Despite intense research, it is still not clear why some individuals develop chronic pain while others do not or how to heal this disease. In this review, we argue for a multisystem approach to understand chronic pain. Pain is not only to be viewed simply as a result of aberrant neuronal activity but also as a result of adverse early-life experiences that impact an individual's endocrine, immune, and nervous systems and changes which in turn program the pain system. First, we give an overview of the ontogeny of the central nervous system, endocrine, and immune systems and their windows of vulnerability. Thereafter, we summarize human and animal findings from our laboratories and others that point to an important role of the endocrine and immune systems in modulating pain sensitivity. Taking "early-life history" into account, together with the past and current immunological and endocrine status of chronic pain patients, is a necessary step to understand chronic pain pathophysiology and assist clinicians in tailoring the best therapeutic approach.

Depressive symptom composites associated with cortisol stress reactivity in adolescents

BACKGROUND

Altered hypothalamic-pituitary-adrenal (HPA) function is common in youth with major depressive disorder (MDD) but variability in the strength and direction of HPA alterations has prompted a search for symptom-based subtypes with unique neuroendocrine signatures. This study investigated the extent to which depressive symptom composites were differentially associated with cortisol responses to psychosocial stress.

METHODS

This study examined salivary cortisol responses to the Trier Social Stress Test (TSST) in 145 adolescents who varied in their risk for MDD: 38 had current MDD; 35 were healthy but at high risk for MDD based on having one or both parents with unipolar MDD; and 72 were healthy youth with no personal or family history of a psychiatric disorder. Multilevel models examined within-person change in cortisol levels during a 2-h resting phase prior to the TSST and both linear and quadratic changes in cortisol levels following the TSST.

RESULTS

Anticipatory cortisol reactivity was lower in MDD youth compared to low-risk youth, and in youth with higher compared to lower depressive symptom severity. Whereas affective symptoms were associated with increased anticipatory cortisol reactivity and more rapid recovery to the TSST, neurovegetative symptoms were associated with decreased anticipatory cortisol reactivity and slower recovery.

LIMITATIONS

The cross-sectional design does not permit inferences regarding temporal relations between cortisol responses and depressive symptom composites.

CONCLUSIONS

The present findings suggest that heterogeneity among studies examining HPA reactivity in depressed youth may be driven, in part, by differences in depressive symptom composites across samples.

March 2017 Letters to the Editor-in-Chief

Letters to the Editor-in-Chief of JOSPT as follows: "Regarding 'Unraveling the Complexity of Low Back Pain'" with Authors' Response "Beall's List Has Vanished: What Next?" with Editor-in-Chief Response J Orthop Sports Phys Ther 2017;47(3):219-223. doi:10.2519/jospt.2017.0202.