Functional performance and plasma cytokine levels in elderly women with and without low back pain

Race-specific associations: inflammatory mediators and chronic low back pain

ABSTRACT

Chronic low back pain (cLBP) is a global health crisis that disproportionately burdens non-Hispanic Black (NHB) individuals, compared with those who identify as non-Hispanic White (NHW). Despite the growing personal and societal impact of cLBP, its biological underpinnings remain poorly understood. To elucidate the biological factors that underlie the racial disparities in cLBP, this study sought to determine whether inflammatory mediators associated with pain interference (PI), pain at rest (PAR), and movement-evoked pain (MEP) differ as a function of racial identity. Blood samples were collected from 156 individuals with cLBP (n = 98 NHB participants, n = 58 NHW participants). Enzyme-linked immunosorbent assay and multiplex assays were used to quantify concentrations of proinflammatory (fibrinogen, C-reactive protein [CRP], serum amyloid A, tumor necrosis factor α [TNF-α], and interleukin [IL]-1α, IL-1β, and IL-6) and anti-inflammatory markers (IL-4 and IL-13). Spearman rho correlations were used to assess associations among markers of inflammation and PI, PAR, and MEP using the Brief Pain Inventory-Short Form. Analyses revealed that for NHW patients, CRP, serum amyloid A, and IL-6 were positively associated with cLBP outcomes and IL-4 was inversely associated with PAR and MEP. However, for NHB patients, only IL-1α was positively associated with PAR. Our findings suggest that, while there are associations between inflammation and cLBP outcomes, the biomarkers that underlie the inflammation could very well differ as a function of racialized minority group. However, more research with racially inclusive samples is needed to elucidate the mechanisms that may contribute to racial disparities in cLBP.

The association between inflammatory biomarkers and low back disorder: a systematic review and meta-analysis

INTRODUCTION

Low back disorder (LBD) is a major cause of disability worldwide. Inflammation results in proliferation of cytokines or consequent degradation products (collectively known as inflammatory biomarkers) that activate pain pathways which can result in non-specific LBD. This systematic review and meta-analysis aim to evaluate the relationship between inflammatory biomarkers and clinical outcomes in patients with LBD.

METHODS

The PRISMA guideline was followed for the systematic reivew. Three online databases were searched. Four RCTs and sixteen observational studies with 1142 LBD patients were analysed. The primary outcomes were back and leg pain scores, back-specific disability scores and expression of inflammatory biomarkers. Standardized mean difference (SMD) and their 95% confidence intervals (CI) were evaluated. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to summarize the strength of evidence.

RESULTS

Four RCTs and sixteen observational studies were included in the analysis of 1142 patients with LBD. There was a statistically significant reduction in back pain score and IL-1 beta and increase in the expression of CTX-1 and IL-10 levels post treatment. There was a significant relationship between increase in the expression of MCP- and reduction in the expression of hsCRP with increase in back pain. Significant relationship was also observed between increase in the expression of MCP-1 and reduction in the expression of IL-6 with increase in leg pain. Increase in the expression of IL-8 and reduction in the expression of hsCRP was also associated with increased disability score.

CONCLUSION

Inflammatory biomarkers play a significant role in the pathogenesis of LBD. CTX-1, IL-10 and IL-1 beta may be responsible for the decrease in back pain scores post treatment. There is a relationship between MCP-1, IL-6, IL-8 and hsCRP with clinical and functional assessments for LBD. Further studies will improve understanding of the pathogenesis of LBD and aid in targeted management strategies.

Exploring the association between Frailty Index and low back pain in middle-aged and older Chinese adults: a cross-sectional analysis of data from the China Health and Retirement Longitudinal Study (CHARLS)

OBJECTIVES

This study explored the association between the Frailty Index (FI) and low back pain (LBP) in middle-aged and older Chinese adults. We hypothesised that a higher FI correlates with increased LBP prevalence.

DESIGN

Cross-sectional analysis.

SETTING

The study used data from the China Health and Retirement Longitudinal Study (CHARLS) across various regions of China.

PARTICIPANTS

The analysis included 6375 participants aged 45 and above with complete LBP and FI data from the CHARLS for 2011, 2013 and 2015. We excluded individuals under 45, those with incomplete LBP data, participants with fewer than 30 health deficit items and those missing covariate data.

OUTCOME MEASURES

We constructed an FI consisting of 35 health deficits. Logistic multivariable regression examined the relationship between FI and LBP, using threshold analysis to identify inflection points. Sensitivity analyses were performed to ensure the robustness of the findings.

RESULTS

Of the participants, 27.2% reported LBP. A U-shaped association was observed between FI and LBP, with the highest quartile (Q4, FI ≥0.23) showing more than a twofold increased risk of LBP (OR=2.90, 95% CI: 2.45-3.42, p<0.001). Stratified analysis showed a significant association in participants under 60, particularly in the lowest FI quartile (OR=1.43, 95% CI: 1.14 to 1.79). Sensitivity analysis upheld the robustness of the primary results.

CONCLUSIONS

The findings suggest a complex relationship between frailty and LBP, highlighting the need for early screening and tailored interventions to manage LBP in this demographic. Further research is necessary to understand the mechanisms of this association and to validate the findings through longitudinal studies.

Composite Biomarkers, Behavioral Symptoms, and Comorbidities in Axial Low Back Pain: A Systematic Review

PURPOSE

Proinflammatory cytokines play a critical role in chronic inflammation and pain and contribute to behavioral symptoms (depressive symptoms, anxiety, fatigue, sleep disturbance) and comorbidities (diabetes, cardiac diseases, cancer). Evidence is lacking on the specific proinflammatory cytokines associated with these behavioral symptoms/comorbidities co-occurring with axial low back pain (aLBP). This review aimed to systematically analyze the following: (1) specific proinflammatory cytokines associated with aLBP in adults, (2) associations among proinflammatory cytokines and behavioral symptoms in aLBP, and (3) relationships among proinflammatory cytokines and comorbidities in aLBP, to develop a new clinical framework for future diagnostic and intervention targets for patients with aLBP.

METHODS

Electronic databases, including PubMed/MEDLINE, ProQuest Nursing & Allied Health Source, and CINAHL Complete (EBSCO) were searched for the period January 2012 to February 2023. Eligible studies included cross-sectional, case-control, longitudinal, and cohort studies in which proinflammatory cytokines were reported in adults above 18 years with aLBP. Intervention studies and randomized controlled trails were excluded. The Joanna Briggs Institute (JBI) criteria were used for quality evaluation.

RESULTS

Findings from 11 studies showed 3 proinflammatory cytokines associated with pain intensity in adult patients with aLBP: C-Reactive Protein (CRP), Tumor Necrosis Factor (TNF-α), and Interleukin (IL-6). Some studies assessed associations between proinflammatory cytokines and depressive symptoms; none explored the association of proinflammatory cytokines with fatigue, anxiety, sleep disturbance, or comorbidities (diabetes, cardiac diseases, and cancer) in aLBP.

CONCLUSIONS

Proinflammatory cytokines in aLBP can serve as composite biomarkers for pain, associated symptoms, and comorbidities and may serve as a target for future interventions. There is need for well-designed studies assessing associations among chronic inflammation, behavioral symptoms, and comorbidities.

The importance of inflammatory biomarkers in non-specific acute and chronic low back pain: a systematic review

OBJECTIVE

The purpose of this study was to systematically review the evidence on inflammatory biomarkers as analytic predictors of non-specific low back pain (NsLBP). Low back pain (LBP) is the number one cause of disability globally, posing a major health problem that causes an enormous social and economic burden, and there is an increasing interest on the importance of biomarkers in quantifying and even emerge as potential therapeutic tools to LBP.

METHODS

A systematic search was conducted on July 2022 in Cochrane Library, MEDLINE and Web of Science for all the available literature. Cross-sectional, longitudinal cohort or case-control studies that evaluated the relationship between inflammatory biomarkers collected from blood samples and low back pain in humans were considered eligible for inclusion, as well as prospective and retrospective studies.

RESULTS

The systematic database search resulted in a total of 4016 records, of which 15 articles were included for synthesis. Sample size comprised a total of 14,555 patients with LBP (acute LBP (n = 2073); chronic LBP (n = 12482)) and 494 controls. Most studies found a positive correlation between classic pro-inflammatory biomarkers and NsLBP, namely C-reactive protein (CRP), interleukin 1 (IL-1) and IL-1β, interleukin 6 (IL-6) and tumour necrosis factor α (TNF-α). On the other hand, anti-inflammatory biomarker interleukin 10 (IL-10) demonstrated a negative association with NsLBP. Four studies have made direct comparisons between ALBP and CLBP groups regarding their inflammatory biomarkers profile.

CONCLUSIONS

This systematic review found evidence of increased levels of pro-inflammatory biomarkers CRP, IL-6 and TNF-α and decreased levels of anti-inflammatory biomarker IL-10 in patients with LBP. Hs-CRP was not correlated with LBP. There is insufficient evidence to associate these findings with the degree of pain severity or the activity status of the lumbar pain over time.

Analysis of intervertebral disc CCR6 and IL-6 gene levels with short-term postoperative low back pain after spinal fusion in lumbar degenerative disease

Background

Previous studies have reported that specific pro-inflammatory cytokines or chemokines are more highly expressed in painful than in nonpainful intervertebral discs (IVDs). However, few studies have investigated their correlation with postsurgical outcomes or the relationship between postoperative pain and inflammatory cytokines in IVDs. Thus, the present study examined the correlation among the gene expression levels of pro-inflammatory cytokines and chemokines in IVD tissues removed during surgery and low back pain (LBP), leg pain (LP), and leg numbness (LN) at one year after spinal fusion surgery in patients with a lumbar degenerative disease (LDD).

Methods

Chemokine and cytokine gene expression levels were measured in IVD samples from 48 patients with LDD. The associations between chemokine and cytokine gene expression levels and pain intensity (numeric rating scale [NRS]) were also analyzed. A correlation analysis was performed between gene expression in each IVD and preoperative and postoperative pain intensity.

Results

In the preoperative analysis, CCR6 was associated with NRS_LBP (r = -0.291, P = 0.045). Postoperative pain analysis revealed correlations between postoperative NRS_LBP and CCR6 (r = -0.328, P = 0.023) and between postoperative NRS_LBP and IL-6 (r = -0.382, P = 0.007). Furthermore, patients with high postoperative LBP intensity (NRS_LBP ≥ 7) also had high LBP intensity (NRS_LBP ≥ 6) before surgery, and a correlation was observed (r = 0.418, P = 0.003). None of the gene mRNAs correlated with NRS_LP or NRS_LN, respectively.

Conclusions

CCR6 and IL-6 gene expression in the IVD was associated with postoperative LBP intensity and may indicate a need for postoperative pain management.

The impact of low back pain and disability on frailty levels in older women: longitudinal data from the BACE-Brazil cohort

METHODS

This is a longitudinal observational study with a convenience subsample from the international Back Complaints in the Elders (BACE)-Brazil. Frailty was assessed by researchers at baseline, 6 and 12 months according to the Frailty Phenotype. Pain was assessed using a Numerical Pain Scale (NPS). Disability was assessed using the Roland Morris Disability Questionnaire.

RESULTS

A total of 155 older women (70.4 ± 5.4 years) participated. Follow-up for 6 and 12 months in this study was associated with a change of older women to worse frailty levels (OR = 2.83, 95% CI 1.98-4.67; p < 0.01). A significant association was observed between greater pain intensity and the transition of the older women through the frailty levels (β = - 0.73; p < 0.01) when inserting the pain variable at baseline of the statistical model. Older women who reported greater pain intensity worsened their frailty level. The same happened when the disability variable was inserted in the model (β = - 0.74; p < 0.01). The criteria proposed by Fried et al. were able to identify frailty throughout the follow-up and no prevalence of any item.

CONCLUSIONS

In older women, relevant factors such as pain and disability are closely linked to the frailty phenomenon. Thus, the frailty syndrome must be assessed, monitored and treated in relation to the individualities of older adults, as those with back pain and greater disabilities are more susceptible to frailty.

Immune-inflammatory and hypothalamic-pituitary-adrenal axis biomarkers are altered in patients with non-specific low back pain: A systematic review

This systematic review aimed to investigate immune-inflammatory and hypothalamic-pituitary-adrenal (HPA) axis biomarkers in individuals with non-specific low back pain (NSLBP) compared to healthy control. The search was performed in five databases until 4 November 2021. Two reviewers independently conducted screenings, data extraction, risk of bias, and methodological quality assessment of 14 unique studies. All studies reported the source of the fluid analyzed: nine studies used serum, two used plasma, one used serum and plasma, and two studies used salivary cortisol. We found preliminary and limited evidence (only one study for each biomarker) of increased levels in growth differentiation factor 15 (GDF-15), interleukin-23 (IL-23), transforming growth factor–beta (TGF-β), and soluble tumor necrosis factor receptor 1 (sTNF-R1) in NSLBP. Inconsistent and limited evidence was identified for interleukin-10 (IL-10). Although C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor–alpha (TNF-α) levels appear to increase in NSLBP, only one study per each biomarker reported statistically significant differences. Interleukin-1 beta (IL-1β), interleukin-17 (IL-17), interferon gamma (IFN-γ), and high-sensitivity CRP (hsCRP) showed no significant differences. Regarding cortisol, one study showed a significant increase and another a significant decrease. More robust evidence between GDF-15, IL-23, TGF-β, and sTNF-R1 with NSLBP is needed. Moreover, contrary to the findings reported in previous studies, when comparing results exclusively with healthy control, insufficient robust evidence for IL-6, TNF-α, and CRP was found in NSLBP. In addition, cortisol response (HPA-related biomarker) showed a dysregulated functioning in NSLBP, with incongruent evidence regarding its directionality. Therefore, our effort is to find adjusted evidence to conclude which immune-inflammatory and HPA axis biomarkers are altered in NSLBP and how much their levels are affected.

Do people with low back pain walk differently? A systematic review and meta-analysis

BACKGROUND

The biomechanics of the trunk and lower limbs during walking and running gait are frequently assessed in individuals with low back pain (LBP). Despite substantial research, it is still unclear whether consistent and generalizable changes in walking or running gait occur in association with LBP. The purpose of this systematic review was to identify whether there are differences in biomechanics during walking and running gait in individuals with acute and persistent LBP compared with back-healthy controls.

METHODS

A search was conducted in PubMed, CINAHL, SPORTDiscus, and PsycINFO in June 2019 and was repeated in December 2020. Studies were included if they reported biomechanical characteristics of individuals with and without LBP during steady-state or perturbed walking and running. Biomechanical data included spatiotemporal, kinematic, kinetic, and electromyography variables. The reporting quality and potential for bias of each study was assessed. Data were pooled where possible to compare the standardized mean differences (SMD) between back pain and back-healthy control groups.

RESULTS

Ninety-seven studies were included and reviewed. Two studies investigated acute pain and the rest investigated persistent pain. Nine studies investigated running gait. Of the studies, 20% had high reporting quality/low risk of bias. In comparison with back-healthy controls, individuals with persistent LBP walked slower (SMD = -0.59, 95% confidence interval (95%CI): -0.77 to -0.42)) and with shorter stride length (SMD = -0.38, 95%CI: -0.60 to -0.16). There were no differences in the amplitude of motion in the thoracic or lumbar spine, pelvis, or hips in individuals with LBP. During walking, coordination of motion between the thorax and the lumbar spine/pelvis was significantly more in-phase in the persistent LBP groups (SMD = -0.60, 95%CI: -0.90 to -0.30), and individuals with persistent LBP exhibited greater amplitude of activation in the paraspinal muscles (SMD = 0.52, 95%CI: 0.23-0.80). There were no consistent differences in running biomechanics between groups.

CONCLUSION

There is moderate-to-strong evidence that individuals with persistent LBP demonstrate differences in walking gait compared to back-healthy controls.

The effect of kinesiophobia in older people with acute low back pain: longitudinal data from Back Complaints in the Elders (BACE)

This study aimed to investigate the course of low back pain (LBP) intensity over a period of 12 months in older people with and without kinesiophobia.This was an international multicenter study. LBP intensity was examined by using the Numerical Pain Scale at baseline and over five follow-up periods. The Fear-Avoidance Beliefs Questionnaire was used to measure patients' beliefs and fears. The study included 532 older adults (non kinesiophobic = 227; kinesiophobic = 305). The individuals had moderate pain at baseline, with a significant difference observed between the groups. Participants showed a rapid improvement in the first 6 weeks, followed by minor improvements in the succeeding months. However, a significant difference between groups remained during the follow-up period. Independently, kinesiophobia is a significant prognostic factor. These findings suggest the importance of screening for psychosocial factors in the management of older patients with LBP. Practice implications: patients need to be warned that pain can be perpetuated by inappropriate avoidance behaviors that may later lead to disability.

Pain Is Associated With Poor Balance in Community-Dwelling Older Adults: A Systematic Review and Meta-analysis

OBJECTIVES

Pain is a risk factor for falls in older adults, but the mechanisms are not well understood, limiting our ability to implement effective preventive strategies. The aim of this study was to systematically review and synthesize the literature that has examined the impact of pain on static, dynamic, multicomponent, and reactive balance in community-dwelling older adults.

DESIGN

Systematic review and meta-analysis.

SETTING AND PARTICIPANTS

Studies from inception to March 2019 were identified from electronic databases (MEDLINE, EMBASE, PsycINFO, CINAHL), contact with the primary authors, and reference lists of included articles.

METHODS

Cross-sectional and case-control studies that compared objective balance measures between older (minimum age 60 years) adults with and without pain were included.

RESULTS

Thirty-nine eligible studies (n = 17,626) were identified. All balance modalities (static, dynamic, multicomponent, and reactive) were significantly poorer in participants with pain compared to those without pain. Subgroup analyses revealed that chronic pain (pain persisting ≥3 months) impaired balance more than pain of unspecified duration. The effects of pain at specific sites (neck, lower back, hip, knee, and foot) on balance were not significantly different.

CONCLUSIONS AND IMPLICATIONS

Pain is associated with poor static, dynamic, multicomponent, and reactive balance in community-dwelling older adults. Pain in the neck, lower back, hip, knee, and foot all contribute to poor balance, and this is even more pronounced for chronic pain. Comprehensive balance and pain characteristic assessments may reveal mechanisms underlying the contribution of pain to instability and increased fall risk in older people.

Physical Abilities in Low Back Pain Patients: A Cross-Sectional Study with Exploratory Comparison of Patient Subgroups

An abundance of literature has investigated the association between low back pain (LBP) and physical ability or function. It has been shown that LBP patients display reduced range of motion, decreased balance ability, impaired proprioception, and lower strength compared to asymptomatic persons. The aim of this study was to investigate the differences between LBP patients and healthy controls in terms of several physical abilities. Based on the premised that different biomechanical and physiological causes and consequences could be related to different types of LBP, a secondary exploratory attempt of the study was to examine the differences between LBP subgroups based on the pain location (local or referred) or type of pathology (discogenic or degenerative) on the level of impairment of function and ability. Participants performed range of motion tests, trunk maximal voluntary contraction force tests, a sitting balance assessment, the timed up-and-go test, the chair rise test, and the trunk reposition error test. Compared to the control group, symptomatic patients on average showed 45.7% lower trunk extension (p < 0.001, η² = 0.33) and 27.7 % lower trunk flexion force (p < 0.001, η² = 0.37) during maximal voluntary contraction. LBP patients exhibited decreased sitting balance ability and lower scores in mobility tests (all p < 0.001). There were no differences between groups in Schober’s test and trunk repositioning error (p > 0.05). No differences were observed among the LBP subgroups. The exploratory analyses are limited by the sample size and uncertain validity of the diagnostic procedures within this study. Further studies with appropriate diagnostic procedures and perhaps a different subgrouping of the LBP patients are needed to elucidate if different types of LBP are related to altered biomechanics, physiology, and function.

Effectiveness of specific stabilization exercise compared with traditional trunk exercise in women with non-specific low back pain: a pilot randomized controlled trial

Background

Non-specific low back pain (LBP) is the leading cause of disability worldwide. The primary physiotherapeutic treatment for LBP is physical exercise, but evidence suggesting a specific exercise as most appropriate for any given case is limited.

Objective

To determine if specific stabilization exercise (SSE) is more effective than traditional trunk exercise (TTE) in reducing levels of pain, disability and inflammation in women with non-specific low back pain (LBP).

Design

A pilot randomized controlled trial was conducted in Rovira i Virgili University, Catalonia.

Methods

Thirty-nine females experiencing non-specific LBP were included in two groups: the TTE program and SSE program, both were conducted by a physiotherapist during twenty sessions. The primary outcome was pain intensity (10-cm Visual Analogue Scale). Secondary outcomes were disability (Roland Morris Disability Questionnaire), and inflammation (IL-6 and TNF-α plasma levels). Measurements were taken at baseline, at half intervention, at post-intervention, and a month later.

Results

Mean group differences in change from baseline to post-intervention for TTE were: -4.5 points (CI 3.3 to 5.6) for pain, -5.1 points (CI 3.0 to 7.3) for disability, 0.19 pg/mL (95% CI [-1.6-1.2]) for IL-6 levels, and 46.2 pg/mL (CI 13.0 to 85.3) for TNF-α levels. For SSE, differences were: -4.3 points (CI 3.1 to 5.6) for pain, -6.1 points (CI 3.7 to 8.6) for disability, 1.1 pg/mL (CI 0.0 to 2.1) for IL-6 levels , and 12.8 pg/mL (95% CI [-42.3-16.7]) for TNF-α levels. There were an insignificant effect size and no statistically significant overall mean differences between both groups.

Conclusion

This study suggests that both interventions (traditional trunk and specific stabilization exercises) are effective in reducing pain and disability in non-specific LBP patients, but the two programs produce different degrees of inflammation change.

Clinical trial registration number

NCT02103036.

Photobiomodulation Therapy is Able to Modulate PGE2 Levels in Patients With Chronic Non-Specific Low Back Pain: A Randomized Placebo-Controlled Trial

BACKGROUND AND OBJECTIVES

Non-specific low back pain (LBP) is responsible for triggering increased biomarkers levels. In this way, photobiomodulation therapy (PBMT) may be an interesting alternative to treat these patients. One of the possible biological mechanisms of PBMT involved to decrease pain intensity in patients with musculoskeletal disorders is modulation of the inflammatory mediators' levels. The aim of this study was to evaluate the effects of PBMT compared with placebo on inflammatory mediators' levels and pain intensity in patients with chronic non-specific LBP.

STUDY DESIGN/MATERIALS AND METHODS

A prospectively registered, randomized triple-blinded (volunteers, therapists, and assessors), placebo-controlled trial was performed. Eighteen patients with chronic non-specific LBP were recruited and treated with a single session of active PBMT or placebo PBMT. The primary outcome of the study was serum prostaglandin E₂ levels and the secondary outcomes were tumor necrosis factor-α, interleukin-6 levels, and pain intensity. All outcomes were measured before and after 15 minutes of treatment session.

RESULTS

PBMT was able to decrease prostaglandin E₂ levels at post-treatment compared with placebo, with a mean difference of -1470 pg/ml, 95% confidence interval -2906 to -33.67 in patients with LBP. There was no difference between groups in the other measured outcomes. Patients did not report any adverse events.

CONCLUSION

Our results suggest that PBMT was able to modulate prostaglandin E₂ levels, indicating that this may be one of the mechanisms involved in the analgesic effects of PBMT in patients with LBP. Trial registration number (ClinicalTrials.gov): NCT03859505. Lasers Surg. Med. © 2020 The Authors. Lasers in Surgery and Medicine published by Wiley Periodicals, Inc.

A systematic review of the role of inflammatory biomarkers in acute, subacute and chronic non-specific low back pain

Background

Low back pain (LBP) is one of the greatest contributors to disability in the world and there is growing interest on the role of biomarkers in LBP. To purpose of this review was to analyze available evidence on the relationship between inflammatory biomarkers, clinical presentation, and outcomes in patients with acute, subacute and chronic non-specific low back pain (NSLBP).

Methods

A search was performed in Medline, Embase, Cinahl and Amed databases. Studies which measured levels of inflammatory biomarkers in participants with NSLBP were included. Two reviewers independently screened titles and abstracts, full-texts, and extracted data from included studies. Methodological quality was assessed using the Newcastle Ottawa Quality Assessment Scale. Level of evidence was assessed using the modified GRADE approach for prognostic studies.

Results

Seven primary studies were included in this review. All results assessed using the modified GRADE demonstrated low to very low quality evidence given the small number of studies and small sample. Three studies examined C-reactive protein (CRP), one of which found significantly higher CRP levels in an acute NSLBP group than in controls and an association between high pain intensity and elevated CRP. Three studies examined tumor necrosis factor alpha (TNF-α), two of which found elevated TNF-α in chronic NSLBP participants compared to controls. Two studies examined interleukin 6 (IL-6), none of which found a significant difference in IL-6 levels between NSLBP groups and controls. Two studies examined interleukin 1 beta (IL-β), none of which found a significant difference in IL-β levels between NSLBP groups and controls.

Conclusions

This review found evidence of elevated CRP in individuals with acute NSLBP and elevated TNF-Α in individuals with chronic NSLBP. There are a limited number of high-quality studies evaluating similar patient groups and similar biomarkers, which limits the conclusion of this review.

Biopsychosocial factors associated with disability in older adults with acute low back pain: BACE-Brasil study

This cross-sectional study evaluated the association of biopsychosocial factors with disability in older adults with a new episode of acute low back pain. Older patients with a new episode of acute low back pain were included and those with cognitive alterations and severe motor impairment were excluded. Disability was assessed using the Roland Morris Disability Questionnaire. The biopsychosocial factors (clinical, functional, health status, psychological and social variables) were evaluated by a structured multidimensional questionnaire and physical examination. A multivariate linear regression was used to analyze data with a statistical significance of 0.05. A total of 386 older individuals with a mean age of 71.6 (± 4.2) years and disability of 13.7 (± 5.7) points were enrolled. Our regression analyses identified that worse physical and mental health (assessed through SF-36), low falls self-efficacy, trouble sleeping due to pain, worse kinesiophobia levels, higher body mass indexes, lumbar morning stiffness, increased pain intensity, female gender and worse functional mobility were significantly associated with baseline disability (p < 0.05). Low back pain-related disability is significantly associated with worse biopsychosocial health conditions in older adults.

Effects of photobiomodulation therapy on inflammatory mediators in patients with chronic non-specific low back pain: Protocol for a randomized placebo-controlled trial

INTRODUCTION

Low back pain (LBP) is ranked as one of the most prevalent health conditions. It is likely that some inflammatory mediators could be associated with pain and disability in these patients. Photobiomodulation therapy (PBMT) is a non-pharmacological therapy often used in patients with LBP and one of the possible mechanisms of action of therapy is modulate inflammatory mediators. However, to date there are no studies that evaluated the effects of PBMT on the levels of inflammatory mediators in patients with LBP. The aim of this study is to evaluate the acute effects of PBMT on systemic levels of inflammatory mediators and pain intensity in patients with chronic non-specific low back pain.

METHODS AND ANALYSIS

This is a prospectively registered, two-arm randomized placebo-controlled trial with blinded patients, assessors and therapists. Eighteen patients with chronic non-specific LBP will be randomized into 2 groups: placebo or active PBMT. The treatment will be provided in a single session. The primary outcome will be levels of prostaglandin E2 (PGE2). The secondary outcomes will be levels of necrosis factor alpha (TNF-α), interleukin 6 (IL-6) and pain intensity. Biochemical and clinical outcomes will be measured at baseline and 15 minutes after the single treatment session.

DISCUSSION

Despite PBMT be used in musculoskeletal disorders such as LBP, to the best of our knowledge this is the first study that will investigate a possible biological mechanism behind the positive clinical effects of PBMT on non-specific chronic low back pain.

ETHICS AND DISSEMINATION

The study was approved by the Regional Research Ethics Committee. The results will be disseminated through publication in peer-reviewed international journal and conferences.

TRIAL REGISTRATION NUMBER

NCT03859505.

The association between pro-inflammatory biomarkers and nonspecific low back pain: a systematic review

BACKGROUND CONTEXT

About 85% of the patients with low back pain seeking medical care have nonspecific low back pain (NsLBP), implying that no definitive cause can be identified. Nonspecific low back pain is defined as low back pain and disability which cannot be linked to an underlying pathology, such as cancer, spinal osteomyelitis, fracture, spinal stenosis, cauda equine, ankylosing spondylitis, and visceral-referred pain. Many pain conditions are linked with elevated serum levels of pro-inflammatory biomarkers. Outcomes of interest are NsLBP and the level of pro-inflammatory biomarkers.

PURPOSE

To unravel the etiology and get better insight in the prognosis of NsLBP, the aim of this study was to assess the association between pro-inflammatory biomarkers and the presence and severity of NsLBP.

STUDY DESIGN

A systematic literature search was made in Embase, Medline, Cinahl, Webof-science, and Google scholar up to January 19th 2017.

METHODS

Included were cross-sectional and cohort studies reporting on patients aged over 18 years with NsLBP, in which one or more pro-inflammatory biomarkers were measured in blood plasma. The methodological quality of the included studies was assessed using the Newcastle Ottawa Scale. A best-evidence synthesis was used to summarize the results from the individual studies, meaning that the included studies were ranked according to the consistency of the findings and according to their methodological quality score using the Newcastle Ottawa Scale.

RESULTS

Included were 10 studies which assessed four different pro-inflammatory biomarkers. For the association between the presence of NsLBP and C-reactive protein (CRP), interleukin 6 (IL-6) and tumor necrosis factor (TNF)-α limited, conflicting and moderate evidence, respectively, was found. For the association between the severity of NsLBP and CRP and IL-6, moderate evidence was found. For the association between the severity of NsLBP and TNF-α and RANTES Regulated on Activation, Normal T Cell Expressed and Secreted conflicting and limited evidence, respectively, was found.

CONCLUSIONS

This study found moderate evidence for (i) a positive association between the pro-inflammatory biomarkers CRP and IL-6 and the severity of NsLBP, and (ii) a positive association between TNF-α and the presence of NsLBP. Conflicting and limited evidence was found for the association between TNF-α and Regulated on Activation, Normal T Cell Expressed and Secreted and severity of NsLBP, respectively.

Adipsin Concentrations Are Associated with Back Pain Independently of Adiposity in Overweight or Obese Adults

Objective: To compare cardiometabolic risk factors including cytokine and adipokine concentrations between individuals with and without back pain. Methods: In 62 overweight/obese adults (BMI ≥ 25 kg/m2; 23F/39M), we collected data on: self-reported back pain; anthropometry [BMI, waist circumference, body composition (dual energy X-ray absorptiometry-DEXA)]; metabolic parameters [fasting glucose; insulin sensitivity (hyperinsulinaemic-euglycaemic clamps)]; cardiovascular parameters (blood pressure, lipids); serum inflammation markers [high-sensitivity C-reactive protein (hsCRP; immunoturbidimetric-assay), tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6, and IL-10 (multiplex-assay)]; and adipokines [leptin, adipsin, resistin, and adiponectin (multiplex-assay)]. Results: Participants who reported having back pain in the past month (n = 24; 39%) had higher BMI (mean ± SD = 33.8 ± 6.3 vs. 30.2 ± 4.1 kg/m2, p = 0.008), fat-mass (39.9 ± 12.3 vs. 33.9 ± 9.8%, p = 0.04), and waist circumference (109.6 ± 16.8 vs. 101.0 ± 9.3 cm, p = 0.01) compared to those without back pain (n = 38; 61%). No differences were observed in cardiometabolic parameters, inflammatory markers, or adiponectin or resistin concentrations. Those reporting back pain had higher adipsin concentrations compared to those without back pain [median (IQR) = 744 (472-2,804) vs. 721 (515-867) ng/ml, p = 0.03], with a trend for higher leptin [5.5 (1.5-24.3) vs. 2.3 (1.5-6.7) ng/ml, p = 0.05], both of which persisted after adjustment for age and sex. Adipsin remained associated with back pain independently of adiposity (BMI, waist, fat-mass, or total %body fat; all p ≤ 0.03). Conclusions: Greater obesity, and higher adipsin and leptin concentrations were observed in those who reported back pain in the past month compared to those without back pain, and adipsin was associated with back pain independently of adiposity. Larger studies are needed to determine if adipsin could be a novel therapeutic target for prevention and/or treatment of back pain.

Inflammatory Mediators and Pain in the First Year After Acute Episode of Low-Back Pain in Elderly Women: Longitudinal Data from Back Complaints in the Elders-Brazil

OBJECTIVE

The aims of this study were to determine the course of plasma levels of inflammatory mediators (interleukin 6 [IL-6], tumor necrosis factor α [TNF-α], soluble TNF receptor 1 [sTNF-R1]) and the severity of low-back pain (LBP) over 6 to 12 months after an acute episode of LBP in elderly women and to establish an association between inflammatory mediators and LBP recovery.

DESIGN

This was a longitudinal study of a subsample (155 elderly women with acute LBP, aged ≥65 years) of the international Back Complaints in the Elders cohort study. Plasma levels of IL-6, TNF-α, and sTNF-R1 were measured using enzyme-linked immunosorbent assays and pain severity using the numerical pain scale.

RESULTS

There was a decrease in the severity of LBP (P = 0.033) and in the levels of IL-6 and TNF-α (P < 0.001) and an increase in sTNF-R1 (P < 0.001) in the first year after an acute episode of LBP. The probability of occurrence of pain relief at the 12-month follow-up was 2.22 times higher in elderly women who had low levels of IL-6 (<1.58 pg/mL) at baseline.

CONCLUSIONS

Our findings showed a relationship between inflammation and LBP by establishing that low IL-6 plasma levels preceded outcome (LBP recovery), supporting the concept that proinflammatory cytokines promote pain.

The Brazilian Back Complaints in the Elders (Brazilian BACE) study: characteristics of Brazilian older adults with a new episode of low back pain

OBJECTIVE

Low back pain (LBP) is little explored in the aging population especially when considering age-relevant and culturally dependent outcomes. We aimed to describe socio-demographic and clinical characteristics of Brazilian older people with a new episode of LBP presenting to primary care.

METHODS

We sourced baseline information on socio-demographic, pain-related and clinical characteristics from 602 older adults from the Brazilian Back Complaints in the Elders (Brazilian BACE) study. We analyzed differences in pain, disability, functional capacity and psychosocial factors between sub-groups based on age (i.e. participants aged 55-74 or ≥75 years), education (i.e. those with four years or less of schooling or those with more than four years of schooling) and income (i.e. participants who reported earning two or less minimal wages or three and more).

RESULTS

Participants presented severe LBP (7.18/10, SD: 2.59). Younger participants were slightly more disabled (mean difference 1.29 points, 95% confidence interval [CI]: 0.03/5.56), reporting poorer physical health, and less fall-related self-efficacy (mean difference of 2.41, 95% CI 0.35/4.46). Those less educated, and those with income equal or less than two minimum wages had more disability, pain catastrophizing and worse functional capacity.

CONCLUSIONS

This was the first study showing that Brazilian older adults with LBP present high levels of functional disability and psychological distress, especially those with low socioeconomic status.

Brain-derived neurotrophic factor plasma levels are increased in older women after an acute episode of low back pain

BACKGROUND

Low back pain (LBP) is a growing public health problem in old age, and it is associated with disabling pain and depressive disorders. We compared brain-derived neurotrophic factor (BDNF) plasma levels, a key neurotrophin in pain modulation, between older women after an acute episode of LBP and age-matched pain-free controls, and investigated potential differences in BDNF levels between controls and LBP subgroups based on pain severity, presence of depressive symptoms and use of analgesic and antidepressant drugs.

METHODS

A total of 221 participants (154 with LBP and 67 pain-free) were studied. A comprehensive assessment of sociodemographic and clinical variables was conducted including pain severity (11-point NRS), depressive symptoms (GDS-15), age, body mass index, physical activity and total number of comorbidities and medications in use.

RESULTS

BDNF levels in LBP group were significantly higher than controls (7515.9±3021.2; Md=7116.0 vs 6331.8±3364.0; Md=5897.5pg/mL, P=0.005). LBP subgroups exhibited higher BDNF levels than controls, regardless of pain severity, presence of depressive symptoms and use of analgesic drugs. BDNF levels were significantly higher in LBP subgroup without use of antidepressant drugs compared to both controls and LBP subgroup with use of antidepressant drugs.

DISCUSSION

This study provides evidence that older women with acute low back pain exhibit higher BDNF plasma levels compared to pain-free controls. Subgroup comparisons suggest that use of pain-relief drugs may influence BDNF levels. The study results offer a novel target for research on mechanisms of back pain in older adults.