Post-traumatic Stress Disorder Symptoms are Associated With Incident Chronic Back Pain: A Longitudinal Twin Study of Older Male Veterans

Chronic restraint stress induces abnormal behaviors in pain sensitivity and cognitive function in mice: the role of Keap1/Nrf2 pathway

Stress is a series of physical and psychological responses to external and internal environmental stimuli. Growing studies have demonstrated the detrimental impacts of acute restraint stress (ARS) and chronic restraint stress (CRS) on animal behavior. However, the related pathogenesis and therapeutic mechanisms remain unclear. Hence, the present study aimed to examine whether unfolded protein response (UPR) and Kelch-like ECH-associated protein 1 (Keap1)-nuclear factor erythroid 2 related factor 2 (Nrf2) pathway are associated with ARS- and CRS- induced abnormal behaviors of pain sensitivity and cognitive function. We here used four behavioral tests to evaluate pain sensitivity and cognitive function in ARS and CRS mice. CRS markedly decreased Paw Withdrawal Mechanical Threshold (PWMT) and Tail-flick Latency (TFL) scores, whereas ARS altered TFL but had no effect on PWMT scores. Additionally, CRS, but not ARS, significantly changed behaviors in nest building behavior and MWMT. Intriguingly, the expression of Keap1 and Nrf2 protein were decreased in the spinal cord and hippocampus in CRS mice, but not in ARS mice. Moreover, neither the ARS nor the CRS groups significantly differed from the control group in terms of endoplasmic reticulum stress (ERS). Taken together, this study demonstrated that CRS could induce abnormal pain sensitivity and cognitive function probably via Keap1/Nrf2 pathway in spinal cord and hippocampus. It is therefore likely that effective intervention of Keap1/Nrf2 pathway may contribute to preventing and treating hyperalgesia and cognitive dysfunction in CRS.

Is There an Association between Post-Traumatic Stress Disorder and the Incidence of Chronic Low Back Pain?

BACKGROUND

Preliminary research suggests post-traumatic stress disorder (PTSD) is a risk factor for chronic low back pain (CLBP). However, this literature displays some limitations. Therefore, this study aimed to investigate the association between PTSD and the 10-year cumulative incidence of CLBP in adults from Germany.

METHODS

The present retrospective cohort study included adults diagnosed with PTSD in 1 of 1284 general practices in Germany in 2005-2020 (index date). Individuals without PTSD were matched to those with PTSD (1:1) using a propensity score based on age, sex, index year, duration of follow-up, and the mean number of consultations during follow-up. In patients without PTSD, the index date was a randomly selected visit date.

RESULTS

There were 60,664 patients included in the study. After adjusting for frequent comorbidities, there was a positive but non-significant association between PTSD and incident CLBP in the overall population (HR = 1.07, 95% CI = 0.99-1.15). Nonetheless, the relationship between PTSD and CLBP was statistically significant in the age group >60 years (HR = 1.24, 95% CI = 1.05-1.46).

CONCLUSIONS

Conversely to previous research, PTSD was not associated with incident CLBP in this large German sample. Further longitudinal studies are warranted to corroborate these findings before drawing any firm conclusions.

Primary Care Considerations for Elderly U.S. Veterans of World War II and the Korean War: A Narrative Review

Many of the United States' more than 18 million veterans obtain healthcare through the Department of Veterans Affairs' (VA) Veterans Health Administration system; however, recent legislative changes have expanded veterans' access to non-VA care in their communities, particularly for those who do not live near VA medical centers. Veterans are seen by physicians in outpatient practice across the United States and are admitted to non-VA hospitals; this is particularly salient for older veterans, who may require a more frequent and high level of care. We present a review of characteristics of U.S. veterans from two conflicts: World War II (WWII) and the Korean War. While non-VA clinicians are well equipped to provide care for patients of all different ages, veterans of armed conflicts have a unique constellation of exposures and cultural considerations that must be accounted for when providing them care. In this review, we describe characteristics of the generations of American veterans who served in WWII and the Korean War conflicts in a brief historical context. We then note conflict-specific exposures and potential long-term sequelae to watch for during physical examinations and to monitor thereafter, age-specific health and emotional concerns, and best practices for providing care to this cohort of veterans.

Stress and Pain. Predictive (Neuro)Pattern Identification for Chronic Back Pain: A Longitudinal Observational Study

Introduction

Low back pain (LBP) leads to considerable impairment of quality of life worldwide and is often accompanied by psychosomatic symptoms.

Objectives

First, to assess the association between stress and chronic low back pain (CLBP) and its simultaneous appearance with fatigue and depression as a symptom triad. Second, to identify the most predictive stress-related pattern set for CLBP for a 1-year diagnosis.

Methods

In a 1-year observational study with four measurement points, a total of 140 volunteers (aged 18–45 years with intermittent pain) were recruited. The primary outcomes were pain [characteristic pain intensity (CPI), subjective pain disability (DISS)], fatigue, and depressive mood. Stress was assessed as chronic stress, perceived stress, effort reward imbalance, life events, and physiological markers [allostatic load index (ALI), hair cortisol concentration (HCC)]. Multiple linear regression models and selection procedures for model shrinkage and variable selection (least absolute shrinkage and selection operator) were applied. Prediction accuracy was calculated by root mean squared error (RMSE) and receiver-operating characteristic curves.

Results

There were 110 participants completed the baseline assessments (28.2 ± 7.5 years, 38.1% female), including HCC, and a further of 46 participants agreed to ALI laboratory measurements. Different stress types were associated with LBP, CLBP, fatigue, and depressive mood and its joint occurrence as a symptom triad at baseline; mainly social-related stress types were of relevance. Work-related stress, such as “excessive demands at work”[b = 0.51 (95%CI -0.23, 1.25), p = 0.18] played a role for upcoming chronic pain disability. “Social overload” [b = 0.45 (95%CI -0.06, 0.96), p = 0.080] and “over-commitment at work” [b = 0.28 (95%CI -0.39, 0.95), p = 0.42] were associated with an upcoming depressive mood within 1-year. Finally, seven psychometric (CPI: RMSE = 12.63; DISS: RMSE = 9.81) and five biomarkers (CPI: RMSE = 12.21; DISS: RMSE = 8.94) could be derived as the most predictive pattern set for a 1-year prediction of CLBP. The biomarker set showed an apparent area under the curve of 0.88 for CPI and 0.99 for DISS.

Conclusion

Stress disrupts allostasis and favors the development of chronic pain, fatigue, and depression and the emergence of a “hypocortisolemic symptom triad,” whereby the social-related stressors play a significant role. For translational medicine, a predictive pattern set could be derived which enables to diagnose the individuals at higher risk for the upcoming pain disorders and can be used in practice.

The Flares of Low back pain with Activity Research Study (FLAReS): study protocol for a case-crossover study nested within a cohort study

BACKGROUND

Although it is generally accepted that physical activity and flares of low back pain (LBP) are related, evidence for the directionality of this association is mixed. The Flares of Low back pain with Activity Research Study (FLAReS) takes a novel approach to distinguish the short-term effects of specific physical activities on LBP flares from the cumulative effects of such activities, by conducting a longitudinal case-crossover study nested within a cohort study. The first aim is to estimate the short-term effects (≤ 24 h) of specific physical activities on LBP flares among Veterans in primary care in the Veterans Affairs healthcare system. The second aim is to estimate the cumulative effects of specific activities on LBP-related functional limitations at 1-year follow-up.

METHODS

Up to 550 adults of working age (18-65 years) seen for LBP in primary care complete up to 36 "Scheduled" surveys over 1-year follow-up, and also complete unscheduled "Flare Window" surveys after the onset of new flares. Each survey asks about current flares and other factors associated with LBP. Surveys also inquire about activity exposures over the 24 h, and 2 h, prior to the time of survey completion (during non-flare periods) or prior to the time of flare onset (during flares). Other questions evaluate the number, intensity, duration, and/or other characteristics of activity exposures. Other exposures include factors related to mood, lifestyle, exercise, concurrent treatments, and injuries. Some participants wear actigraphy devices for weeks 1-4 of the study. The first aim will examine associations between 10 specific activity categories and participant-reported flares over 1-year follow-up. The second aim will examine associations between the frequency of exposure to 10 activity categories over weeks 1-4 of follow-up and long-term functional limitations at 12 months. All analyses will use a biopsychosocial framework accounting for potential confounders and effect modifiers.

DISCUSSION

FLAReS will provide empirically derived estimates of both the short-term and cumulative effects of specific physical activities for Veterans with LBP, helping to better understand the role of physical activities in those with LBP.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04828330 , registered April 2, 2021.

Rehabilitation for Low Back Pain: A Narrative Review for Managing Pain and Improving Function in Acute and Chronic Conditions

Low back pain (LBP) is prevalent and may transition into chronic LBP (cLBP) with associated reduced quality of life, pain, and disability. Because cLBP affects a heterogenous population, rehabilitation efforts must be individualized to meet the needs of various patient populations as well as individuals. This narrative review evaluated the many approaches to LBP rehabilitation including treatment-based classifications and specific types of rehabilitation efforts from exercise and physical therapy to spinal manipulation and bracing. Clinicians caring for patients with LBP or cLBP must be aware of the various options to find the right treatment course for each patient. In many cases, with proper patient expectations and care, nonpharmacological options may suffice to manage cLBP. While there is a rightful role for analgesics in the management of LBP, nonpharmacological options should be seriously considered, as they can play an important and health-sustaining role in patient management.

ISSLS Prize in Clinical Science 2020. Examining causal effects of body mass index on back pain: a Mendelian randomization study

PURPOSE

Measures of body fat accumulation are associated with back pain, but a causal association is unclear. We hypothesized that BMI would have causal effects on back pain. We conducted a two-sample Mendelian randomization (MR) study to assess the causal effect of body mass index (BMI) on the outcomes of (1) back pain and (2) chronic back pain (duration > 3 months).

METHODS

We identified genetic instrumental variables for BMI (n = 60 variants) from a meta-analysis of genome-wide association studies (GWAS) conducted by the Genetic Investigation of ANthropometric Traits consortium in individuals of European ancestry (n = 322,154). We conducted GWAS of back pain and chronic back pain (n = 453,860) in a non-overlapping sample of individuals of European ancestry. We used inverse-variance weighted (IVW) meta-analysis as the primary method to estimate causal effects.

RESULTS

The IVW analysis showed evidence supporting a causal association of BMI on back pain, with a 1-standard deviation (4.65 kg/m²) increase in BMI conferring 1.15 times the odds of back pain (95% confidence interval [CI]: 1.06-1.25, p = 0.001]; effects were directionally consistent in secondary analysis and sensitivity analyses. The IVW analysis supported a causal association of BMI on chronic back pain (OR 1.20 per 1 SD deviation increase in BMI [95% CI 1.09-1.32; p = 0.0002]), and effects were directionally consistent in secondary analysis and sensitivity analyses.

CONCLUSION

In this first MR study of BMI and back pain, we found a significant causal effect of BMI on both back pain and chronic back pain. These slides can be retrieved under Electronic Supplementary Material.