Physical activity behavior predicts endogenous pain modulation in older adults

Associations of pain sensitivity and conditioned pain modulation with physical activity: findings from the Multicenter Osteoarthritis Study (MOST)

OBJECTIVE

Individuals with chronic pain due to knee osteoarthritis (OA) are insufficiently physically active, and alterations of facilitatory and inhibitory nociceptive signaling are common in this population. Our objective was to examine the association of these alterations in nociceptive signaling with objective accelerometer-based measures of physical activity in a large observational cohort.

DESIGN

We used data from the Multicenter Osteoarthritis Study. Measures of peripheral and central pain sensitivity included pressure pain threshold at the knee and mechanical temporal summation at the wrist, respectively. The presence of descending pain inhibition was assessed by conditioned pain modulation (CPM). Physical activity was quantitatively assessed over 7 days using a lower back-worn activity monitor. Summary metrics included steps/day, activity intensity, and sedentary time. Linear regression analyses were used to evaluate the association of pain sensitivity and the presence of descending pain inhibition with physical activity measures.

RESULTS

Data from 1873 participants was analyzed (55.9% female, age = 62.8 ± 10.0 years). People having greater peripheral and central sensitivity showed lower step counts. CPM was not significantly related to any of the physical activity measures, and none of the exposures were significantly related to sedentary time.

CONCLUSIONS

In this cohort, greater peripheral and central sensitivity were associated with reduced levels of objectively-assessed daily step counts. Further research may investigate ways to modify or treat heightened pain sensitivity as a means to increase physical activity in older adults with knee OA.

Preliminary Characterization of Age and Chronic Low Back Pain Effects on Multimodal Pain Sensitivity: A Comparison Study in Older Adults with and Without Chronic Low Back Pain

Though pain sensitivity impairments contribute to chronic pain in younger adults, it is unclear if pain hypersensitivity manifests with aging and is heightened in the geriatric chronic low back pain population. The cross-sectional study preliminarily addressed this gap by measuring pain sensitivity in older adults with chronic low back pain (n = 25) as well as pain-free sex-matched older (n = 25) and younger adults (n = 25). Pain sensitivity was quantified by 8 distinct measures that were subdivided as static (ie, pressure pain thresholds, heat pain thresholds, fixed mechanical pain, and fixed cold pain) and dynamic pain sensitivity (ie, mechanical temporal summation, thermal ramp and hold, heat pain aftersensations, and conditioned pain modulation). Test-retest reliability values for pain sensitivity ranged from moderate to excellent (intraclass correlation coefficients ≥ .500; p's < .05). The main effect for the group was significant (partial η2 = .413, P < .001), revealing between-group differences in pain sensitivity on 5 out of 8 tests (p's ≤ .043). Predominantly, both older adult groups demonstrated increased pain facilitation and decreased pain inhibition during dynamic pain sensitivity testing compared to pain-free younger adults (p's ≤ .044). Despite qualitative differences, static and dynamic pain sensitivity responses were statistically similar between older adults with and without chronic LBP (p's > .05). Findings suggest pain sensitivity can be reliably measured in older adults and that pain hypersensitivity develops with chronological aging, providing partial support for the theory that pain hypersensitivity may impact geriatric chronic pain populations. Further study is needed to more definitively parse out whether pain hypersensitivity is comparatively heightened in older adults with chronic LBP beyond the influence of chronological aging. PERSPECTIVE: This article establishes that surrogate measures of centrally mediated pain sensitization are heightened with aging. Impaired endogenous pain modulation may influence chronic pain development, maintenance, treatment efficacy, and/or ensuing disability, necessitating research to comprehensively characterize how pain hypersensitivity contributes to geriatric chronic pain conditions.

Physical activity is predictive of conditioned pain modulation in healthy individuals: a cross-sectional study

Even in healthy populations, conditioned pain modulation (CPM) magnitude varies. This may be accounted for by (non-)modifiable factors, including physical activity. Yet, little research has thoroughly examined physical activity and its relation with CPM magnitude in a representative sample. Therefore, the present study investigated the predictive effect of physical activity on CPM magnitude in 105 healthy adults. Physical activity was assessed during seven consecutive days by self-report using the International Physical Activity Questionnaire and by monitored-based accelerometry. CPM was examined using a heterotopic noxious conditioning stimulation protocol during which the effect of a hot water conditioning stimulus on pressure pain thresholds was evaluated. Comparative, correlation, and hierarchical linear regression analyses were performed. Report-based walking predicts 4.8% of variance in pain modulatory capacity, moderate physical activity predicts 10.2% of variance in pain modulatory capacity, and report-based time spent on total physical activity predicts 7.0% of variance in pain modulatory capacity. More MET-minutes/week spent on total physical activity, including walking and moderate physical activity is associated with greater pain modulatory capacity. The findings of this study add to the limited evidence on the predictive effect of physical activity on CPM. It urges to consider physical activity a confounding factor when examining CPM. The current study provides evidence that a physically active lifestyle benefits endogenous pain modulation in healthy adults. Given its potential, walking and moderate-intensity physical activity might be achievable treatment strategies for pain patients known to have impaired CPM. PERSPECTIVE: The results of this article show that a physically active lifestyle including larger amounts of walking and moderate activity predict greater pain modulatory capacity. TRIAL REGISTRATION: This study has not been preregistered.

CPM-Related Mechanisms Could Play a Key Role in the Effects on Pain Sensitivity Induced by Manual Therapy: Three Crossover Trials Investigating the Effects of Manual Pressure

Objective: The aim of this study is to assess whether pain-inducing manual pressure (PIMP) leads to effects on pressure pain threshold (PPT) mediated by conditioned pain modulation (CPM) and whether these effects are influenced by the intensity and repetition of the stimulus. Additionally, the influence of psychological factors and physical activity on the response to PIMP was explored. Methods: A total of 72 pain-free students were randomly assigned to three crossover trials. Trial 1 compared the effects of PIMP with the cold pressor task and pain-inducing electrostimulation. Trial 2 compared the effects of manual pressure that elicited moderate pain, mild pain, and no pain. Trial 3 compared a single PIMP stimulation with four stimuli applied at the same site or at different sites. Results: PIMP produced a lower increase in PPT than cold pressor task and no difference with electrostimulation. Manual pressure that caused moderate pain led to a greater increase in PPT compared to mild pain and pain-free application. Repetition of PIMP stimulus, whether at the same or different sites, did not significantly increase PPT compared to a single stimulation. No association with psychological factors or physical activity was found. Conclusions: PIMP produces an increase in PPT, suggesting the involvement of CPM-related mechanisms.

Deciphering nociplastic pain: clinical features, risk factors and potential mechanisms

Nociplastic pain is a mechanistic term used to describe pain that arises or is sustained by altered nociception, despite the absence of tissue damage. Although nociplastic pain has distinct pathophysiology from nociceptive and neuropathic pain, these pain mechanisms often coincide within individuals, which contributes to the intractability of chronic pain. Key symptoms of nociplastic pain include pain in multiple body regions, fatigue, sleep disturbances, cognitive dysfunction, depression and anxiety. Individuals with nociplastic pain are often diffusely tender - indicative of hyperalgesia and/or allodynia - and are often more sensitive than others to non-painful sensory stimuli such as lights, odours and noises. This Review summarizes the risk factors, clinical presentation and treatment of nociplastic pain, and describes how alterations in brain function and structure, immune processing and peripheral factors might contribute to the nociplastic pain phenotype. This article concludes with a discussion of two proposed subtypes of nociplastic pain that reflect distinct neurobiological features and treatment responsivity.

The Efficacy of the Addition of tDCS and TENS to an Education and Exercise Program in Subjects with Knee Osteoarthritis: A Randomized Controlled Trial

Knee osteoarthritis (KOA) has a significant impact on patients' quality of life. This study aimed to assess the effectiveness of integrating transcranial direct current stimulation (tDCS) and transcutaneous electrical nerve stimulation (TENS) into an education and exercise program with the aim of decreasing pain and improving physical function in KOA. A randomized controlled trial with 65 KOA patients was conducted. The subjects were assigned to one of the following three groups: education and active exercise plus (1) double active tDCS and TENS, (2) active tDCS and sham TENS, and (3) double sham tDCS and TENS. Sessions were conducted over a 20 min period, whilst data on pain, chronic pain clinical variables, and physical function were collected. Although all groups showed improvement in pain-related symptoms in the short and medium term, the addition of tDCS and/or TENS did not significantly enhance the benefits of the exercise and education program. These findings suggest that an education and active exercise program in the treatment of KOA has a positive effect on pain, with or without the addition of tDCS and/or TENS.

A decision tree algorithm to identify predictors of post-stroke complex regional pain syndrome

This prospective cohort study aimed to identify the risk factors for post-stroke complex regional pain syndrome (CRPS) using a decision tree algorithm while comprehensively assessing upper limb and lower limb disuse and physical inactivity. Upper limb disuse (Fugl-Meyer assessment of upper extremity [FMA-UE], Action Research Arm Test, Motor Activity Log), lower limb disuse (Fugl-Meyer Assessment of lower extremity [FMA-LE]), balance performance (Berg balance scale), and physical inactivity time (International Physical Activity Questionnaire-Short Form [IPAQ-SF]) of 195 stroke patients who visited the Kishiwada Rehabilitation Hospital were assessed at admission. The incidence of post-stroke CRPS was 15.4% in all stroke patients 3 months after admission. The IPAQ, FMA-UE, and FMA-LE were extracted as risk factors for post-stroke CRPS. According to the decision tree algorithm, the incidence of post-stroke CRPS was 1.5% in patients with a short physical inactivity time (IPAQ-SF < 635), while it increased to 84.6% in patients with a long inactivity time (IPAQ-SF ≥ 635) and severe disuse of upper and lower limbs (FMA-UE score < 19.5; FMA-LE score < 16.5). The incidence of post-stroke CRPS may increase with lower-limb disuse and physical inactivity, in addition to upper-limb disuse. Increasing physical activity and addressing lower- and upper-limb motor paralysis may reduce post-stroke CRPS.

Vagal tone, pain sensitivity and exercise-induced hypoalgesia: The effect of physical activity level

BACKGROUND

Vagal activity has analgesic effects that are attributed to exercise-induced hypoalgesia (EIH). High vagal tone and low pain sensitivity are reported in individuals who routinely exercise yet, their association is unclear. Furthermore, it is unknown if the heightened vagal tone following high physical activity predicts and intensifies EIH.

METHODS

Fifty-one healthy participants (27 low-moderately physically active; 27 females) underwent a resting-state electrocardiogram followed by heart rate variability analysis. Pain measurements, including pressure (PPT) and heat (HPT) pain thresholds, ratings of tonic heat pain (THP) and conditioned pain modulation (CPM) paradigm, were conducted pre- and post-exercise on a cycle ergometer.

RESULTS

The highly active group demonstrated higher vagal tone compared to the low-moderately active (root mean square of successive differences between R-R intervals: 63.96.92 vs. 34.78 ms, p = 0.018; percentage of successive R-R intervals that exceed 50 ms: 24.41 vs. 11.52%, p = 0.012). Based on repeated-measure ANOVA, the highly active group showed higher PPT at pre-exercise, compared to the low-moderately active group (382 kPa vs. 327 kPa; p = 0.007). Post-exercise, both groups demonstrated EIH, increased HPT (p = 0.013) and decreased THP ratings (p < 0.001). Linear regression revealed that only in the low-moderately active group, higher vagal tone was associated with more efficient pre-exercise CPM and a greater reduction in THP ratings post-exercise (p ≤ 0.01).

CONCLUSIONS

Highly active individuals demonstrate greater vagal tone and lower pain sensitivity but no greater EIH. Vagal tone moderates pain inhibition efficiency and EIH only in low-moderately active individuals. These findings suggest that physical activity level moderates the vagal-pain association via the endogenous analgesia system.

SIGNIFICANCE

Highly physically active individuals exhibit greater vagal tone and reduced sensitivity to experimental pain, yet they do not benefit more from exercise-induced hypoalgesia (EIH) compared to low-moderately active individuals. Moreover, low-moderately active individuals with greater vagal tone exhibited more efficient endogenous pain inhibition and greater EIH, suggestive of the moderation effect of physical activity level on vagal-pain associations.

Exercise effect on pain is associated with negative and positive affective components: A large-scale internet-based cross-sectional study in Japan

Pain is a global health problem that leads to sedentary behavior and tends to cause negative emotion. In contrast, exercise is widely recommended for a health promotion, while pain often worsens with physical activity. Although exercise therapy is often prescribed to people with pain, the mechanisms of exercise effect on pain remains unclear. In this study, we tried to identify a universal association factor between regular exercise and pain intensity utilizing a cross-sectional web-based survey involving 52,353 adult participants from a large national study conducted in Japan. Using principal component analysis, we uncovered a mediation model of exercise effect on pain through psychological components. Analyses were performed in half of the population with pain (n = 20,330) and validated in the other half (n = 20,330), and showed that high-frequency exercise had a significant association with reduction in pain intensity. We also found Negative Affect and Vigor, two psychological components, are fully associating the exercise effect on pain (indirect effect =  - 0.032, p < 0.001; association proportion = 0.99) with a dose-dependent response corresponding to the frequency of exercise. These findings were successfully validated (indirect effect of high-frequency exercise =  - 0.028, p < 0.001; association proportion = 0.85). Moreover, these findings were also identified in subpopulation analyses of people with low back, neck, knee pain, and the tendency of the exercise effect on pain was increased with older people. In conclusion, the effect of exercise on pain is associated with psychological components and these association effects increased in parallel with the frequency of exercise habit regardless pain location.

Associations Between Patterns of Daily Stepping Behavior, Health-Related Quality of Life, and Pain Symptoms Among Older Adults with Chronic Pain: A Secondary Analysis of Two Randomized Controlled Trials

Purpose

One's amount, intensity, and distribution of physical activity may have implications for whether it has positive or negative effects on pain and quality of life for older adults living with chronic pain. Thus, we investigated baseline patterns of stepping related to pain symptoms and health-related quality of life at baseline and over a 12-week follow-up period.

Patients and Methods

Participants were low-active older adults (69.54±6.74 years) with obesity and chronic pain who enrolled in one of two randomized controlled trials. Participants completed measures of pain intensity, interference, and health-related quality of life and wore an accelerometer for 7 days at baseline and week 12. Functional principal components analysis identified patterns of within-day stepping behavior at baseline, and linear regressions were used to investigate how these component scores related to pain and health-related quality of life at baseline and over 12 weeks.

Results

Two patterns were extracted; one describing more vs less stepping and the second capturing movement later vs earlier in the day. More baseline stepping was associated with better physical functioning (B=0.148, p<0.001) and energy (B=0.073, p=0.033), while a later start in the day was associated with worse social functioning (B=-0.193, p=0.031). More stepping at baseline predicted positive changes in physical functioning (B=0.094, p=0.019), emotional role limitations (B=0.132, p=0.049), energy (B=0.112, p<0.001), social functioning (B=0.086, p=0.043), pain (B=0.086, p=0.009), general health (B=0.081, p=0.003) and pain intensity (B=-0.039, p=0.003). A later start to the day was associated with worsening physical functioning (B=-0.229, p<0.001), physical (B=-0.282, p=0.047) and emotional role limitations (B=-0.254, p=0.048), general health (B=-0.108, p=0.041), and pain interference (B=0.055, p=0.043).

Conclusion

Findings suggest there is value in activity patterns as an indicator for additional behavioral intervention, as those who move little and/or delay daily movement are likely to experience subsequent decrements in quality of life and pain symptoms.

Pain-phenotyping in osteoarthritis: Current concepts, evidence, and considerations towards a comprehensive framework for assessment and treatment

Objectives

Pain as central symptom of osteoarthritis (OA) needs to be addressed as part of successful treatment. The assessment of pain as feature of disease or outcome in clinical practice and drug development remains a challenge due to its multidimensionality and the plethora of confounders. This article aims at providing insights into our understanding of OA pain-phenotypes and suggests a framework for systematic and comprehensive assessments.

Methods

This narrative review is based on a search of current literature for various combinations of the search terms "pain-phenotype" and "knee OA" and summarizes current knowledge on OA pain-phenotypes, putting OA pain and its assessment into perspective of current research efforts.

Results

Pain is a complex phenomenon, not necessarily associated with tissue damage. Various pain-phenotypes have been described in knee OA. Among those, a phenotype with high pain levels not necessarily matching structural changes and a phenotype with low pain levels and impact are relatively consistent. Further subgroups can be differentiated based on patient reported outcome measures, assessments of comorbidities, anxiety and depression, sleep, activity and objective measures such as quantitative sensory testing.

Conclusions

The complexity of both OA as disease and pain in OA prompt the definition of a set of variables that facilitate assessments comparable across studies to maximize our understanding of pain, as central concern for the patient.

Physical activity and endogenous pain modulation in older people: a scoping review protocol

OBJECTIVE

This scoping review aims to provide an overview of the existing literature on physical activity and endogenous pain modulation (EPM), assessed using conditioned pain modulation (CPM), with a specific focus on older people with chronic pain.

INTRODUCTION

Approximately 20% of the European population reports chronic pain, highlighting the problem of chronic pain in the general population. This prevalence increases to 50% in older people. Physical activity is one of the most frequently used treatments for pain management and relief. A possible mechanism underlying the positive effects of physical activity on pain may be related to its influence on EPM. The review will map i) types of physical activity used to study its effect on EPM in older people; ii) intervention protocols investigating physical activity and EPM, measured using CPM, in older people experiencing pain; and iii) knowledge gaps requiring further research or interventions adapted to older people with pain.

INCLUSION CRITERIA

This review will consider studies of people aged 60 years or older, using CPM to examine the effect of physical activity on EPM. All types of care settings will be eligible.

METHODS

This review will be conducted in accordance with the JBI methodology for scoping reviews. The following databases will be searched: MEDLINE (Ovid), CINAHL (EBSCOhost), Embase, Cochrane Library, Web of Science, JBI Evidence Synthesis , PsycINFO, and PEDro.

REVIEW REGISTRATION

Open Science Framework https://osf.io/e7ndy/.

The Role of Physical Exercise in Chronic Musculoskeletal Pain: Best Medicine-A Narrative Review

The aim of this paper is to provide a narrative review of the effects of physical exercise in the treatment of chronic musculoskeletal pain. Physical inactivity and sedentary behavior are associated with chronic musculoskeletal pain and can aggravate it. For the management of musculoskeletal pain, physical exercise is an effective, cheap, and safe therapeutic option, given that it does not produce the adverse effects of pharmacological treatments or invasive techniques. In addition to its analgesic capacity, physical exercise has an effect on other pain-related areas, such as sleep quality, activities of daily living, quality of life, physical function, and emotion. In general, even during periods of acute pain, maintaining a minimum level of physical activity can be beneficial. Programs that combine several of the various exercise modalities (aerobic, strengthening, flexibility, and balance), known as multicomponent exercise, can be more effective and better adapted to clinical conditions. For chronic pain, the greatest benefits typically occur with programs performed at light-to-moderate intensity and at a frequency of two to three times per week for at least 4 weeks. Exercise programs should be tailored to the specific needs of each patient based on clinical guidelines and World Health Organization recommendations. Given that adherence to physical exercise is a major problem, it is important to empower patients and facilitate lifestyle change. There is strong evidence of the analgesic effect of physical exercise in multiple pathologies, such as in osteoarthritis, chronic low back pain, rheumatoid arthritis, and fibromyalgia.

The association between objectively measured preoperative light-intensity physical activity and postoperative ambulation in patients with gastrointestinal cancer

[Purpose] To clarify the association between preoperative physical activity and postoperative ambulation based on physical activity intensity, and independent of functional capacity and depression, in patients with gastrointestinal cancer. [Participants and Methods] Seventy patients who underwent surgery for primary colorectal or gastric cancer were enrolled. Preoperative moderate-to-vigorous-intensity physical activity, light-intensity physical activity, and sedentary behavior were assessed using an accelerometer. The primary outcome was the days to postoperative first ambulation (capable of independently and continuously walking 150 m). Functional capacity and depression, as confounders, were evaluated by measuring the 6-minute walk distance and using the Hospital Anxiety and Depression Scale. [Results] Of the 70 patients, 28 had insufficient accelerometer data, and 42 were included in the analysis. Preoperative light-intensity physical activity, but not moderate-to-vigorous-intensity physical activity and sedentary behavior, was negatively associated with the days to postoperative first ambulation, after adjusting for age, preoperative functional capacity, and preoperative depression. [Conclusion] Preoperative light-intensity physical activity was associated with the days to postoperative ambulation independently of age, functional capacity, and depression. Hence, predicting delayed ambulation by preoperative light-intensity physical activity in patients with gastrointestinal cancer may be useful.

Lifestyle factors and psychological factors are associated with central pain processing in service members with persistent low-back pain: A cross-sectional exploratory study

Persistent low-back pain (LBP) is highly prevalent in the military. Altered central pain processing is one of the mechanisms found to underlie persistent LBP. Our aim was to explore which factors are associated with altered pain processing in Dutch service members with persistent LBP. This knowledge may guide clinicians in what factors to address in the treatment of dysfunctional pain processing in service members with persistent LBP. Twenty-one service members with persistent LBP (mean age 34.0 years, 18 males) were included in this cross-sectional exploratory study. Participants completed questionnaires regarding lifestyle and psychological factors. Altered central pain processing was measured by temporal summation of pain to examine the function of the pain facilitatory system and by conditioned pain modulation to examine the pain inhibitory function. Univariable and multivariable linear regression analyses were performed. A higher local temporal summation of pain was associated with a longer sitting time, a higher level of physical activity and a higher level of pain catastrophizing. A higher local conditioned pain modulation was associated with a higher level of pain catastrophizing, anxiety and depression symptoms, and with a lower sleep quality. A higher remote conditioned pain modulation effect was associated with a higher level of physical activity, a higher body mass index and a shorter sitting time. This study succeeded in identifying lifestyle and psychological factors associated with altered pain processing in service members with persistent LBP. Prospective studies are needed to examine causality in these relationships.

Physical activity, sitting time, and thermal quantitative sensory testing responses in African Americans

Introduction

Prior research suggests that African Americans (AAs) have more frequent, intense, and debilitating pain and functional disability compared with non-Hispanic Whites (NHWs). Potential contributing factors to this disparity are physical activity and sedentary behavior, given that AAs are less physically active, and physical activity is associated with antinociception (whereas sedentary behavior is linked to pronociception). However, impact of these factors on pain processing has largely been unexplored in AAs, especially before chronic pain onset.

Objective

This study examined relationships between physical activity, sedentary behavior (sitting time), and laboratory measures of pain and pain modulation in adult AAs. These included heat pain threshold and tolerance, temporal summation of pain (TSP, a marker of central sensitization), and conditioned pain modulation (CPM, a marker of descending pain inhibition).

Methods

Multiple regressions were conducted to examine the effects of physical activity and sitting time on heat threshold and tolerance. Multilevel models were conducted to assess the relationship between physical activity, sitting time, and temporal summation of pain. Additional multilevel models were conducted to assess the relationship between physical activity, sitting time, and conditioned pain modulation.

Results

Higher level of physical activity, but not sitting time, was associated with reduced TSP slopes. Neither physical activity nor sitting time was associated with CPM slopes. No significant relationships between physical activity or sitting time and heat pain threshold or tolerance were detected.

Conclusions

These findings suggest that physical activity is associated with reduced TSP, an effect which may be driven by reduced spinal hyperexcitability in more active individuals. Thus, structural and individual interventions designed to increase physical activity in healthy, young AAs may be able to promote antinociceptive processes (ie, reduced TSP/reduced pain facilitation) potentially protective against chronic pain.

Sleep characteristics and pain in middle-aged and older adults: Sex-specific impact of physical and sitting activity

OBJECTIVES

The relationship between poor sleep health and worse pain is established. Physical activity has been successful in reducing chronic pain and improving sleep in aging adults. Despite known sex differences (more women than men experiencing chronic pain and insomnia), sex-specific patterns of interactive associations between physical activity, sleep, and pain remain unexplored. This study tested whether physical and sitting activity moderated associations between sleep characteristics and pain intensity, and whether sex further moderated these relationships.

METHODS

Participants aged 50+ (N = 170, Mage = 64.34, 72 women) completed an online survey measuring pre-sleep arousal (Pre-sleep Arousal Scale), sleep (Pittsburgh Sleep Quality Index), past month average pain intensity, and physical activity (International Physical Activity Questionnaire). Multiple regressions evaluated whether minutes of physical activity (total, vigorous, moderate, walking) or sitting activity, pre-sleep arousal, sleep, sex, or their interaction was associated with pain. Analyses controlled for education, difficulty walking, body mass index, total medical conditions, pain medication, and depressive/anxiety symptoms.

RESULTS

In women, vigorous activity interacted with total pre-sleep arousal and somatic pre-sleep arousal in its association with pain. Higher total arousal and somatic arousal were associated with worse pain intensity only for women who reported highest levels of vigorous activity. No such associations were observed for men or for other physical or sitting activity levels.

CONCLUSIONS

Vigorous physical activity may exacerbate the association between more pre-sleep arousal and worse pain in middle-aged and older women. Research should explore potential sex-specific mechanisms (e.g., inflammatory cytokines, arousal neural networks) underlying these results.

Physical Activity to Prevent the Age-Related Decline of Endogenous Pain Modulation

As humans age, the capacity of the central nervous system to endogenously modulate pain significantly deteriorates, thereby increasing the risk for the development of chronic pain. Older adults are the least physically active cohort of all age groups. We hypothesize that a sedentary lifestyle and decreased physical activity may contribute to the decline of endogenous pain modulation associated with aging.

Associations between patterns of physical activity, pain intensity, and interference among older adults with chronic pain: a secondary analysis of two randomized controlled trials

Background: Clinical management of chronic pain often includes recommendations to engage in physical activity (PA), though there are little data on the interplay between pain symptoms and key aspects of PA participation (e.g., intensity and bout duration) among older adults. Herein we investigate the longitudinal relationships between changes in PA behavior and changes in pain intensity and interference among low-active older adults with obesity and chronic pain. Methods: Participants (N = 41) were enrolled in two randomized pilot trials wherein they were assigned to an intervention focused on participation in frequent PA across the day, or to a low-contact control. Participants completed the 3-item PROMIS pain intensity scale and 8-item PROMIS pain interference scale before and after the interventions. Participants also wore an ActivPAL accelerometer for 7 days before and during the final week of the interventions. Results: A series of linear regression analyses demonstrated that increased time spent stepping at a high-light intensity in very short bouts was associated with increased pain intensity scores. By contrast, increased time spent stepping at a high-light intensity in bouts of 5-20 min was associated with reductions in pain intensity and interference scores. Increased time spent stepping at a moderate intensity overall was associated with reduced pain intensity scores, and time spent stepping at a moderate intensity for 10-20 min associated with reduced pain interference. Conclusion: These findings suggest older adults with chronic pain may benefit by moving at high-light or moderate intensities in brief bouts of at least 5 min in duration.

Association between Pain and Frequent Physical Exercise among Adults in the United States: A Cross-Sectional Database Study

Pain affects over 20% of United States adults, and less than 50% of United States adults participate in frequent physical exercise. This cross-sectional database study included 13,758 United States adults aged >18 years from the 2020 Medical Expenditure Panel Survey (MEPS) and analyzed the association between severity of pain (independent variable) and frequent physical exercise (dependent variable), adjusting for demographic, economic, limitation, and health variables using multivariable logistic regression. The study showed 50.3% of adults report frequently exercising. Only 37.1% of adults reported experiencing pain of any degree, with a majority of them experiencing little pain. In the adjusted model, extreme pain vs. none, quite a bit of pain vs. none, Hispanic vs. non-Hispanic ethnicity, having a functional limitation vs. no limitation, and being overweight/obese vs. not being obese/overweight were associated with lower odds of reporting doing frequent physical exercise. Meanwhile, being ≥65 or 40-64 vs. 18-39 years of age, male vs. female, white vs. not white race, private or public vs. no health coverage, and good vs. poor general health were associated with greater odds of reporting doing frequent physical exercise. These variables associated with frequent physical exercise should be considered in future work when designing health interventions.

The Association of Pain with Incident Falls in People with Chronic Obstructive Pulmonary Disease: Evidence from the English Longitudinal Study of Ageing

People with chronic obstructive pulmonary disease (COPD) have a higher prevalence of pain and a greater risk of falls than their healthy peers. As pain has been associated with an increased risk of falls in older adults, this study investigated the association between pain and falls in people with COPD compared to healthy controls. Data from the English Longitudinal Study of Ageing were used to establish an association between pain and falls when modelled with a generalised ordinal logistic regression and adjusted for sex, age, wealth, and education (complete case analysis only; n = 806 COPD, n = 3898 healthy controls). The odds were then converted to the predicted probabilities of falling. The predicted probability of falling for people with COPD was greater across all pain categories than for healthy controls; for COPD with (predicted probability % [95%CI]), no pain was 20% [17 to 25], with mild pain was 28% [18 to 38], with moderate pain was 28% [22 to 34] with severe pain was 39% [30 to 47] and for healthy controls with no pain was 17% [16 to 18], mild pain 22% [18 to 27], moderate pain 25% [20 to 29] and severe pain 27% [20 to 35]. The probability of falling increased across pain categories in individuals with COPD, with the most severe pain category at a nearly 40% probability of falling, indicating a potential interaction between COPD and pain.

Lifestyle factors and long-term survival in patients with chronic non-cancer pain: a nationwide cohort study in South Korea

PURPOSE

This study aimed to investigate the association of modifiable lifestyle factors with long-term survival outcomes in patients with chronic non-cancer pain (CNCP) in South Korea.

METHODS

This population-based cohort study used data from the National Health Insurance Service database in South Korea. We considered three lifestyle factors from the standard health examination (smoking status, alcohol consumption, and physical activity).

RESULTS

A total of 1,298,314 patients with CNCP were analyzed; moreover, the 5-year all-cause mortality rate was 3.3% (42,875 patients). In the multivariable Cox regression model, in the previous-smoker and current-smoker groups, it was 5% (hazard ratio [HR]:1.05, 95% confidence interval [CI]:1.02-1.08; P = 0.003) and 65% (HR: 1.65, 95% CI: 1.60-1.69; P < 0.001) higher, respectively, than that in the never-smoker group. The 5-year all-cause mortality was 19% (HR: 1.19, 95% CI: 1.14-1.24; P < 0.001) higher in the heavy-alcohol-consumption group than in the non-alcohol-consumption group. Compared with those without mild physical activity, patients who engaged in mild physical activity for 1-3 (HR: 0.89, 95% CI: 0.87-0.92; P < 0.001), 4-5 (HR: 0.88, 95% CI: 0.86-0.91; P < 0.001), and 6-7 (HR: 0.90, 95% CI: 0.88-0.93; P < 0.001) days per week exhibited a significantly decreased 5-year all-cause mortality. The association between moderate/intensive physical activity and 5-year all-cause mortality yielded similar results.

CONCLUSION

Lifestyle factors, including previous/current smoking, heavy alcohol consumption, and physical activity, were associated with a higher 5-year all-cause mortality risk among patients with CNCP in South Korea.

Relationship between Physical Activity and Pain in U.S. Adults

PURPOSE

We sought to assess the relationship between physical activity (PA) and pain within the available sample, with secondary aims to assess prevalence of pain, PA levels, health care seeking behaviors, and impact of pain on daily activities and work.

METHODS

We conducted an epidemiological cross-sectional observational study utilizing National Health Interview Survey data from 2020. We examined the self-reported adherence to current PA guidelines and the prevalence of pain. We hypothesized those dealing with pain were less likely to meet PA guidelines. The PA levels, pain prevalence, frequency, and intensity were assessed via the survey and relationships explored via modeling.

RESULTS

Of 31,568, 46% were men and 53.99% women with mean age of 52.27 yr (±17.31 yr). There were 12,429 (39.37%) participants that reported pain on some days, 2761 (8.75%) on most days, and 4661 (14.76%) every day. The odds of engaging in PA decreased in a stepwise fashion based on frequency and intensity of pain reporting when compared with no pain. Importantly, PA is a significant correlate affecting pain reporting, with individuals engaging in PA (strength and aerobic) demonstrating two times lower odds of reporting pain when compared with those not meeting the PA guidelines.

CONCLUSIONS

There is a significant correlation between meeting PA guidelines and pain. Meeting both criteria of PA guidelines resulted in lower odds of reporting pain. In addition, the odds of participating in PA decreased based on pain frequency reporting. These are important findings for clinicians, highlighting the need for assessing PA not only for those dealing with pain but also as a potential risk factor for minimizing development of chronic pain.

Enhanced pain sensitivity in obese patients with obstructive sleep apnoea syndrome is partially reverted by treatment: An exploratory study

BACKGROUND

Obesity is frequently associated with obstructive sleep apnoea syndrome (OSA) and chronic pain. OSA as well as continuous positive airway pressure (CPAP) treatment may modulate the pain perception threshold (PT) in patients with obesity.

METHODS

In this prospective, longitudinal study, all patients admitted for obesity assessment were screened for OSA by nocturnal polygraphy (SOMNOcheck^® , IAH ≥10) and performed mechanical (Von Frey electronic device) and electrical (PainMatcher^® ) pain tests. Those with severe OSA were retested for PT 1 month after initiation of CPAP therapy. Newly diagnosed patients with severe OSA (hypopnea apnoea index >30) have been offered to start CPAP treatment.

RESULTS

Among 85 patients, there were 27 OSA patients, aged between 40 ± 13.2 years with a BMI of 42 ± 7.2 kg/m² . Severe OSA patients (N = 11) showed a lower PT than non-OSA patients (N = 58) during mechanical (177 ± 120 vs. 328 ± 136 g, p < 0.01) and electrical methods (7.4 ± 6.4 vs. 12.9 ± 6.7 stimulation duration steps; p = 0.03). In the severe OSA group (N = 7), an increased PT was observed 1 month after CPAP treatment during mechanical pain testing (298 ± 69 vs. 259 ± 68 g, p < 0.05), but not during electrical pain testing (11.5 ± 3.0 vs. 12.4 ± 3.8 stimulation duration steps, p = 0.50).

CONCLUSION

In patients with obesity, this exploratory study showed that the presence of an OSA is associated with a decreased PT, whereas implantation of a CPAP device tends to normalize pain perception.

Development of a Clinical Prediction Rule for Treatment Success with Transcranial Direct Current Stimulation for Knee Osteoarthritis Pain: A Secondary Analysis of a Double-Blind Randomized Controlled Trial

The study’s objective was to develop a clinical prediction rule that predicts a clinically significant analgesic effect on chronic knee osteoarthritis pain after transcranial direct current stimulation treatment. This is a secondary analysis from a double-blind randomized controlled trial. Data from 51 individuals with chronic knee osteoarthritis pain and an impaired descending pain inhibitory system were used. The intervention comprised a 15-session protocol of anodal primary motor cortex transcranial direct current stimulation. Treatment success was defined by the Western Ontario and McMaster Universities’ Osteoarthritis Index pain subscale. Accuracy statistics were calculated for each potential predictor and for the final model. The final logistic regression model was statistically significant (p < 0.01) and comprised five physical and psychosocial predictor variables that together yielded a positive likelihood ratio of 14.40 (95% CI: 3.66−56.69) and an 85% (95%CI: 60−96%) post-test probability of success. This is the first clinical prediction rule proposed for transcranial direct current stimulation in patients with chronic pain. The model underscores the importance of both physical and psychosocial factors as predictors of the analgesic response to transcranial direct current stimulation treatment. Validation of the proposed clinical prediction rule should be performed in other datasets.

Lean Mass is Associated with, but Does Not Mediate Sex Differences in Pressure Pain Sensitivity in Healthy Adults

Background

Sex differences exist in pain sensitivity, however, the underlying mechanism(s) that explain these differences are not fully understood. Pain sensitivity has been shown to be influenced by body mass index, but limited data exist on the role of body composition on pain sensitivity. The purpose was to examine the influence of body composition on pain sensitivity in males and females.

Methods

This cross-sectional study design used pressure pain thresholds (PPT) of 87 participants (45 female) who were assessed in the vastus lateralis (leg PPT) and brachioradialis (arm PPT) using a pressure algometer. Fat and lean tissue were assessed via dual-energy X-ray absorptiometry (DXA). A two group by two limb, repeated measured ANOVA was used to assess differences between limbs and sex. Spearman correlations and hierarchical regression analyses were employed to determine the association between body composition and PPT.

Results

Males had higher PPTs then females (P<0.05) and had higher DXA assessed lean and lower levels fat mass (P<0.05). Total body and limb specific lean mass was associated with PPTs (r≥0.34; P<0.05). Hierarchical regression analysis revealed lean mass was a significant predictor of 8% of the variance in arm PPT (P<0.006) and 18% of the variance in leg PPT (P<0.001). However, lean mass was not found to statistically mediate the observed sex differences in PPT.

Conclusion

This finding suggests lean mass may play a previously unknown role in sex differences in pressure pain sensitivity. Future studies are needed to confirm this finding and a larger sample size is likely required to have sufficient power to perform the mediation analysis.

A remote group-mediated daylong physical activity intervention for older adults with chronic pain: Results of the MORPH-II randomized pilot trial

Chronic pain is a debilitating condition that affects many older adults who often have limited access to non-pharmacological pain management strategies. One potentially effective and novel lifestyle medicine for chronic pain involves increasing physical activity through frequent movement across the day, thereby also decreasing the presence of extended sedentary bouts. The MORPH-II pilot randomized controlled refinement trial iterated on the MORPH trial, which was a first-of-its-kind group-mediated daylong physical activity (DPA) intervention for older adults with chronic pain rooted in social cognitive and self-determination theories and supported by an mHealth toolset designed to foster social connection and awareness of physical activity patterns. MORPH-II was delivered fully remotely via videoconference software and supported by a technology kit comprising an iPad, activity monitor, and wireless weight scale. It was also implemented a refined coaching model designed to help participants better understand their own patterns of activity. A total of 44 participants were randomized to receive the 12-week group-mediated DPA intervention or to a low-contact control. Qualitative interviews suggest the program was well-received by participants and that participants developed an understanding of how patterns of physical activity related to their pain symptoms. Participants also highlighted several additional areas for refinement related to the coaching model and feedback provided within the mHealth app. Analyses of covariance, controlling for baseline values, revealed a small effect (η 2 = 0.01) on pain intensity favoring the intervention condition, though both groups improved during the study period. There was a large effect favoring the intervention condition on ActivPAL-assessed average daily steps (η 2 = 0.23) and postural shifts (η 2 = 0.24). Control participants spent less time in short sedentary bouts (η 2 = 0.09), and there was a small effect (η 2 = 0.02) indicating intervention participants spent less time in extended sedentary bouts. Finally, relative to control, intervention participants demonstrated a moderate improvement in autonomy satisfaction (η 2 = 0.05), relatedness frustration (η 2 = 0.05), and competence frustration (η 2 = 0.06), and a large magnitude improvement in competence satisfaction (η 2 = 0.22). These findings indicate that the MORPH-II intervention was feasible and acceptable, and may positively impact steps, postural breaks, and several key domains of basic psychological needs detailed in self-determination theory.

An exploration of low back pain beliefs in a Northern America based general population

BACKGROUND

Prior research has demonstrated that people across different populations hold beliefs about low back pain (LBP) that are inconsistent with current evidence. Qualitative research is needed to explore current LBP beliefs in Northern America (NA).

OBJECTIVES

We conducted a primarily qualitative cross-sectional online survey to assess LBP beliefs in a NA population (USA and Canada).

METHODS

Participants were recruited online using social media advertisements targeting individuals in NA over the age of 18 with English speaking and reading comprehension. Participants answered questions regarding the cause of LBP, reasons for reoccurrence or persistence of LBP, and sources of these beliefs. Responses were analyzed using conventional (inductive) content analysis.

RESULTS/FINDINGS

62 participants were included with a mean age of 47.6 years. Most participants reported multiple causes for LBP as well as its persistence and reoccurrence, however, these were biomedically focused with minimal to no regard for psychological or environmental influences. The primary cited source of participants' beliefs was healthcare professionals.

CONCLUSIONS

Our findings align with prior research from other regions, demonstrating a need for updating clinical education and public messaging about the biopsychosocial nature of LBP.

Association between physical activity and musculoskeletal pain: an analysis of international data from the ASAP survey

OBJECTIVE

To explore the association of physical activity (PA) with musculoskeletal pain (MSK pain).

DESIGN

Cross-sectional study SETTING: 14 countries (Argentina, Australia, Austria, Brazil, Chile, France, Germany, Italy, the Netherlands, Singapore, South Africa, Spain, Switzerland and the USA).

PARTICIPANTS

Individuals aged 18 or older.

PRIMARY AND SECONDARY OUTCOME MEASURES

PA volumes were assessed with an adapted version of the Nordic Physical Activity Questionnaire-short. Prevalence of MSK pain was captured by means of a 20-item checklist of body locations. Based on the WHO recommendation on PA, participants were classified as non-compliers (0-150 min/week), compliers (150-300 min/week), double compliers (300-450 min/week), triple compliers (450-600 min/week), quadruple compliers (600-750 min/week), quintuple compliers (750-900 min/week) and top compliers (more than 900 min/week). Multivariate logistic regression was used to obtain adjusted ORs of the association between PA and MSK pain for each body location, correcting for age, sex, employment status and depression risk.

RESULTS

A total of 13 741 participants completed the survey. Compared with non-compliers, compliers had smaller odds of MSK pain in one location (thoracic pain, OR 0.77, 95% CI 0.64 to 0.93). Double compliance was associated with reduced pain occurrence in six locations (elbow, OR 0.70, 95% CI 0.50 to 0.98; forearm, OR 0.63, 95% CI 0.40 to 0.99; wrist, OR 0.74, 95% CI 0.57 to 0.98; hand, OR 0.57, 95% CI 0.40 to 0.79; fingers, OR 0.72, 95% CI 0.52 to 0.99; abdomen, OR 0.61, 95% CI 0.41 to 0.91). Triple to top compliance was also linked with lower odds of MSK pain (five locations in triple compliance, three in quadruple compliance, two in quintuple compliance, three in top compliance), but, at the same time, presented increased odds of MSK pain in some of the other locations.

CONCLUSION

A dose of 300-450 min WHO-equivalent PA/week was associated with lower odds of MSK pain in six body locations. On the other hand, excessive doses of PA were associated with higher odds of pain in certain body locations.

Bidirectional Associations Between Physical Activity and Pain Among Older Adults: An Ecological Momentary Assessment Study

This paper examines the within-day, bidirectional associations between physical activity and self-reported pain among older adults. Older adults (N = 104; range: 60-98 years) participated in a 10-day Ecological Momentary Assessment (EMA) study. Participants received six EMA prompts/day with a single item assessing pain. Participants wore an activPAL monitor measuring step counts. At the within-person level, on occasions when participants took more steps than usual in the 30 min before the EMA prompt, they were more likely to experience pain at the prompt (β^02=0.0003, p < .03). At the between-person level, greater step counts in the 30 min before the EMA prompt, on average, were associated with less pain on occasions when pain was experienced (β^01=-0.0005, p < .04). Pain was not related to subsequent stepping. Bidirectional associations between physical activity and pain were not documented, but physical activity did appear to be related to subsequent pain.

The association between pain and central nervous system depressing medication among hospitalised Norwegian older adults

OBJECTIVES

Central nervous system depressant medications (CNSD) including benzodiazepines, z-hypnotics and opioids are regularly prescribed for the older patient. These medications are linked to dependence and associated with severe side effects in some older patients. Consensus recommendations for this group suggest limiting their use. We have recently described a high proportion of long-term CNSD use and dependence among older in-hospital patients. In this study, we aim to investigate factors associated with pain intensity and presentation of pain among older adults with long-term use of CNSDs compared to non-users.

METHODS

Two hundred and forty six elderly hospitalised patients were recruited consecutively in a cross-sectional study. Data was collected from patients and electronic health records (EHR). Independent variables were sex, age, education, emotional symptoms (hospital anxiety and depression scale [HADS]), cognitive function (Mini-mental State Examination test [MMSE]), comorbidity (cumulative illness rating score - geriatrics [CIRS-G]), loneliness (the six-item De Jong Gierveld Loneliness Scale) and prolonged (≥4 weeks) use of any CNSDs or prolonged use of opioids (≥4 weeks). All variables, including pain intensity, were collected at one time point consistent with the cross-sectional study design. Statistical analyses included descriptive statistics and linear regression models using the above mentioned variables and pain intensity (visual analogue scale for pain intensity [VAS] pain 0-100) as outcome. Additional information regarding pain presentation was extracted from the patients' EHR.

RESULTS

Mean pain intensity VAS (SD) was 35.2 (30.4) and 18.1 (24.2) respectively, for patients with vs. without prolonged use of CNSDs. In the multivariable linear regression analysis, prolonged use of CNSDs and opioids were positively associated with pain intensity (VAS) (regression coefficient (95% CI) 20.7 (11.0; 30.3), p<0.001, and 19.8 (5.7; 33.8), p=0.006, respectively), while sex, age, education, MMSE, HADS, CIRS-G and loneliness scores were not. Pain related to back (23.2%) and lower extremities (23.2%) were most common pain sites, and those with one or more pain sites reported overall higher pain intensity compared to those with no reported pain sites (p<0.006).

CONCLUSIONS

Prolonged use of CNSD medications as well as prolonged use of opioids are both positively associated with pain intensity. The results may have implications for treatment and long-term pain management for older patients.

Body Composition does not influence Conditioned Pain Modulation and Exercise Induced Hyperalgesia in Healthy Males and Females

BACKGROUND

Obese individuals report a higher susceptibility to chronic pain. Females are more likely to have chronic pain and excess adipose tissue. Chronic pain is associated with dysfunctional pain modulatory mechanisms. Body composition differences may be associated with pain modulation differences in males and females. The purpose of this study was to investigate body composition (lean vs fat mass) differences and pain modulatory functioning in healthy males and females.

METHODS

Pressure pain thresholds (PPT) of 96 participants (47M; 49F) were assessed in both arms and legs before and after a double footed ice bath (2°C) for 1min and an isometric knee extension, time to failure task. The difference between post and pre measures was defined conditioned pain modulatory (CPM) response (ice bath) and exercise induced hypoalgesia (EIH) response. Whole body and site-specific fat and lean tissue were assessed via DXA scan.

RESULTS

Sex differences were found in whole body lean mass (61.5±6.7kg vs 41.2±5.4kg; P<0.001) but not fat mass amount (17.2±10.5kg vs 21.0±9.7kg; P=0.068). No effect of sex was found between limb CPM (P=0.237) and limb EIH (P=0.512). When controlling for lean mass there was no significant effect of sex on CPM (P=0.732) or EIH (P=0.474) response. Similar findings were found for fat mass.

CONCLUSION

The lack of difference suggests that males and females have similar modulatory functioning. It appears that in healthy adults free from chronic pain, neither fat mass nor lean mass has an influence on endogenous pain modulatory function.

Adherence to a Mediterranean Lifestyle and Changes in Frequency, Severity, and Localization of Pain in Older Adults

OBJECTIVE

To assess the association between adherence to a Mediterranean lifestyle and changes in pain, and its characteristics over time in older adults.

PATIENTS AND METHODS

We analyzed data from 864 and 862 community-dwelling individuals aged 65+ years from the Study on Cardiovascular Health, Nutrition and Frailty in Older Adults in Spain (Seniors-ENRICA) Seniors-ENRICA-1 (2008-2010 to 2012) and Seniors-ENRICA-2 (2015-2017 to 2019) cohorts, with a median follow-up of 2.8 and 2.4 years, respectively. Adherence to a Mediterranean lifestyle was assessed at baseline with the 27-item Mediterranean lifestyle (MEDLIFE) index. Pain changes over time were calculated with a pain scale that assessed the frequency, severity, and the number of pain locations both at baseline and follow-up. Multivariable-adjusted relative risk ratios (RRRs) were obtained using multinomial logistic regression.

RESULTS

In the pooled cohorts, after a median follow-up of 2.6 years, pain worsened for 697 participants, improved for 734, and did not change for 295. Compared with the lowest category of MEDLIFE adherence, those in the highest category showed an RRR of improvement vs worsening of overall pain of 1.85 (95% CI, 1.28 to 2.67; P-trend<.001). MEDLIFE adherence was also linked to improvement in pain frequency (RRR, 1.98; 95% CI, 1.31 to 3.01; P-trend=.001), pain severity (RRR, 2.00; 95% CI, 1.33 to 3.00; P-trend=.001), and a reduction in the number of pain locations (RRR, 1.68; 95% CI, 1.13 to 2.50; P-trend=.004). Limitations of this study are the use of self-reported lifestyle data.

CONCLUSION

A Mediterranean lifestyle was associated with improvement of pain characteristics in older adults. Experimental studies should assess the efficacy of an integral lifestyle approach for the management of pain in older adults.

Symptomatic but not Asymptomatic COVID-19 Impairs Conditioned Pain Modulation in Young Adults

Pain is a common symptom reported in COVID-19 patients. Impaired endogenous pain-modulatory mechanisms such as conditioned pain modulation (CPM), and exercise-induced hypoalgesia (EIH) have been found in chronic pain conditions but is often overlooked in acute conditions that evoke painful symptoms, such as COVID-19. The purpose was to compare pressure-pain sensitivity, CPM, and EIH function among individuals who previously had COVID-19, both symptomatically and asymptomatically, and a healthy control group. Pressure pain thresholds of 59 participants were assessed in the forearm and leg using a pressure algometer before and after 1) submersion of their dominant foot in cold water (2°C) for 1min; and 2) isometric knee extension performed to task-failure at 25% of their maximal contraction. The CPM response was attenuated in individuals who were infected with symptomatic COVID-19 (N = 26) compared to asymptomatic COVID-19 (N = 13) in arm (-1.0% ± 20.3 vs 33.3% ± 26.2; P < .001) and leg (12.8% ± 22.0 vs 33.8% ± 28.2; P = .014) and compared to controls (N = 20) in arm only (-1.0% ± 26.2 vs 23.4% ± 28.2; P = .004). The EIH response was not different between groups. CPM was impaired in individuals who had symptomatic COVID-19, which may have long-term implications on pain modulation.

Perspective

This study reveals that CPM was impaired in individuals who had symptomatic COVID-19 during the first wave of COVID-19, pre vaccine. These findings present a preliminary motive to study the long-term implications of COVID-19 and its effects on pain modulation.

Impaired conditioned pain modulation was restored after a single exercise session in individuals with and without fibromyalgia

Supplemental Digital Content is Available in the Text.

Submaximal isometric exercise improved impaired conditioned pain modulation acutely in individuals with and without fibromyalgia, regardless of health status.

Introduction:

Exercise is an effective nonpharmacological intervention for individuals with fibromyalgia syndrome (FMS); however, considerable variability is observed in their pain response after a single exercise session that could be due to differences in baseline central pain inhibition (ie, conditioned pain modulation [CPM]).

Objectives:

This study examined the effect of isometric exercise on CPM in people with FMS and control participants. A subaim was to identify whether pain inhibition after exercise was due to differences in baseline CPM.

Methods:

Twenty-one individuals with FMS (50.5 ± 14.9 years) and 22 age-matched and sex-matched controls (49.2 ± 13.3 years) participated in a familiarization session and 2 randomized experimental sessions: (1) low-intensity isometric exercise and (2) quiet rest control. Conditioned pain modulation was measured before and after each experimental session. In addition, body composition and physical activity levels were collected to determine potential group differences.

Results:

Both groups had comparable body composition and physical activity levels and reported similar exercise-induced hypoalgesia (increase in pressure pain thresholds) at the exercising muscle (quadriceps muscle) and systemically (deltoid muscle). Both groups had a decrease in CPM after exercise and quiet rest; however, in both FMS and control participants with impaired baseline CPM, there was an increase in CPM at the deltoid muscle after exercise.

Conclusion:

In persons with low CPM, irrespective of health status, isometric exercise enhanced CPM at a site distal from the exercising muscle. Our results support the use of isometric exercise when initiating an exercise program especially for individuals with impaired CPM.

Kinesiophobia Predicts Physical Function and Physical Activity Levels in Chronic Pain-Free Older Adults

Advanced aging is associated with a general decline in physical function and physical activity. The current evidence suggests that pain-related fear of movement (i.e., kinesiophobia) is increased in the general older adult population and impacts physical activity levels in patients with chronic pain. However, whether kinesiophobia could impact physical activity and function in relatively healthy, chronic pain-free older adults remain unclear. Thus, the purpose of this study was to examine whether fear of movement due to pain predicted self-reported and objective levels of physical function and physical activity in healthy older adults without chronic pain. Fifty-two older adults were enrolled in this study. The participants completed the International Physical Activity Questionnaire (IPAQ) and wore an accelerometer on the hip for 7 days to measure physical activity. Measures of sedentary time, light physical activity, and moderate to vigorous physical activity were obtained from the accelerometer. Measures of physical function included the Physical Functioning subscale of the Short Form-36, Short Physical Performance Battery (SPPB), the 30-s Chair Stand test, and a maximal isometric hand-grip. The Tampa Scale of Kinesiophobia (TSK) was used to measure fear of movement or re-injury associated with pain. Potential covariates included self-reported activity-related pain and demographics. Hierarchical linear regressions were conducted to determine the relationship of kinesiophobia with levels of physical activity and physical function while controlling for activity-related pain and demographics. TSK scores did not predict self-reported physical activity on the IPAQ. However, TSK scores predicted self-reported physical function (Beta = -0.291, p = 0.015), 30-s Chair Stand test scores (Beta = -0.447, p = 0.001), measures from the SPPB (Gait speed time: Beta = 0.486, p < 0.001; Chair stand time: Beta = 0.423, p = 0.003), percentage of time spent in sedentary time (Beta = 0.420, p = 0.002) and light physical activity (Beta = -0.350, p = 0.008), and moderate to vigorous physical activity (Beta = -0.271, p = 0.044), even after controlling for significant covariates. These results suggest that greater pain-related fear of movement/re-injury is associated with lower levels of light and moderate to vigorous physical activity, greater sedentary behavior, and worse physical function in healthy, chronic pain-free older adults. These findings elucidate the potential negative impact of kinesiophobia in older adults who don't report chronic pain.

The effect-modification of physical activity on the association of pain with impaired physical function in aging adults

OBJECTIVES

Pain is prevalent among older adults and may result in impairment in physical function. However, little is known about the effect-modification of this relationship by physical activity (PA) participation. This large and representative study sought to estimate the effect of pain on physical function among older adults in Ghana and evaluate whether PA modifies this association.

METHODS

Data came from 1201 adults aged ≥50 years participating in the AgeHeaPsyWel-HeaSeeB Study in Ghana. Pain constructs were defined using the Medical Outcomes Study Short Form-36 (MOS SF-36). PA was assessed using the International Physical Activity Questionnaire short form (IPAQ-SF) and physical function impairment was measured by seven-item domains based on the activities of daily living (ADL) and instrumental ADL (IADL). Adjusted hierarchical OLS regressions were fitted to estimate the direct and moderating relationships between pain facets, PA, and impaired physical function.

RESULTS

The relationships of pain severity (β = 0.348, p < .001), and pain interference (β = 0.424, p < .001) with impaired physical function were robust after full adjustment for confounding variables. Persons with pain experiences had significantly increased impaired physical function risks. PA significantly modified the association between pain severity (β = -0.232, p < .001) and pain interference (β = -0.143, p < .001) with impaired physical function.

CONCLUSIONS

Our data indicate that the relationships of pain with physical function impairment are modified by PA intensity. Future studies are warranted to understand the indirect effect of pain on functional limitations and how PA promotion could manage pain and improve functional ability in aging adults.

Health-related quality of life among family caregivers of oesophageal cancer survivors one year after curative intended treatment - a nationwide population-based study

BACKGROUND

To investigate factors that might influence the quality of life of the family caregivers of oesophageal cancer patients.

MATERIAL AND METHODS

A cross-sectional study within a prospective, population-based nationwide cohort study including family caregivers to oesophageal cancer patients was conducted. The exposures were family caregivers' age, sex, education level and patients' tumour stage, postoperative complications, weight loss and comorbidities. The outcome was health-related quality of life (HRQL) one year after the patient's cancer surgery measured by the RAND-36. Multivariable linear regression analysis provided mean score differences (MSD) with 95% confidence intervals (CI).

RESULTS

In total 257 family caregivers were included. Family caregivers ≥65 years displayed lower physical function (MSD=-8.5; p = 0.001) but a higher level of energy (MSD = 9.2; p = 0.002). Those with a higher education level had less pain (MSD = 11.2; p = 0.01) and better physical function (MSD = 9.1; p = 0.006).Among the patient related exposures, postoperative complications were associated with family caregivers' physical function (MSD= -6.0; p = 0.01) and pain (MSD= -7.9; p = 0.01). Tumour stage and comorbidities were not associated with the HRQL of the family caregiver.

CONCLUSION

The study suggests that patients' complications and age and education level of the family caregivers are associated with family caregivers HRQL. This information provides guidance in the process of creating support for family caregivers of oesophageal cancer patients.

Stress, non-restorative sleep, and physical inactivity as risk factors for chronic pain in young adults: A cohort study

Background

Chronic pain is a common condition which causes patients much suffering and is very costly to society. Factors known to be associated with chronic pain include female gender, acute pain, depression, and anxiety. This study investigated whether stress, sleep disturbance, and physical inactivity were risk factors for developing chronic pain among young adults, and whether there were any interactions between these.

Methods

This retrospective longitudinal study was based on an existing database from a cohort study on IT use and health, called Health 24 Years. A questionnaire was sent to students aged 19–24 in Sweden for five consecutive years, containing questions on pain, stress, sleep, physical activity, technology use, health, and more. In logistic regressions, stress, sleep, and physical activity at baseline were potential predictors of chronic pain one and four years later. In addition, a new variable including all possible interactions between potential predictors was created to test for effect modification between risk factors.

Results

At the one-year follow-up, stress, non-restorative sleep, and physical inactivity showed odds ratios of 1.6 (95% CI: 1.0–2.4), 1.5 (95% CI: 1.0–2.3), and 1.8 (95% CI: 1.1–3.0) respectively after adjusting for confounders, the reference being non-stressed, having restorative sleep and being active. At the four-year follow-up, stress showed an adjusted odds ratio of 1.9 (95% CI: 1.3–2.9), while non-restorative sleep and physical inactivity were statistically insignificant. At the one-year follow-up, the interaction between risk factors were significant. The most clear example of this effect modification was to be inactive and not have -restorative sleep, compared to individuals who were active and had restorative sleep, showing an adjusted odds ratio of 6.9 (95% CI: 2.5–19.2) for developing chronic pain one year after baseline. This in comparison of odds ratios for only inactive respectively only non-restorative sleep being 1.7 (95% CI: 0.6–5.3) respectively 1.6 (95% CI: 0.7–3.5).

Conclusions

Stress, non-restorative sleep, and physical inactivity were risk factors for developing chronic pain one year after baseline, and stress were also a risk factor four years after baseline. These findings suggest that non-restorative sleep and inactivity are risk factors in the short term while stress is a risk factor in both the short and the long term. In addition to the independent effects of non-restorative sleep and inactivity, their combination seems to further increase the odds of chronic pain.

Impact of Seasonality on Physical Activity: A Systematic Review

BACKGROUND

The purpose of this study was to collect and analyze the available scientific evidence of the impact of seasonality on physical activity (PA). PA refers to walking, biking, sports and/or active recreation.

METHODS

The search was performed in the following databases: PubMed, PEDro, Cochrane and Embase. All publications from January 2015 to September 2020 assessing seasonal variations on physical activity development in adults were selected.

RESULTS

A total of 1159 articles were identified, of which 26 fulfilled the selection criteria involving 9300 participants from 18 different countries. The results obtained suggest that seasonality affects PA independently of the countries, pathologies of the participants and the tool to collect PA information.

CONCLUSIONS

PA level varies across the seasons, with higher PA level in summer compared with other seasons, especially in winter. Sedentary behavior follows the opposite trend. Impact of seasonality variations should be considered in clinical research involving PA as a primary outcome as well as in interventions on PA promotion.

Association between temporal summation and conditioned pain modulation in chronic low back pain: baseline results from 2 clinical trials

Introduction

Temporal summation (TS) and conditioned pain modulation (CPM) represent different aspects of central pain processing. Their relationship and differential performance within distinct body locations are not well understood.

Objectives

To examine the association between TS and CPM in chronic low back pain and the influence of testing location on this relationship.

Methods

We analyzed baseline data from 2 clinical trials on participants with chronic low back pain (n = 264; 47.3% female; mean age = 41 years, SD = 12; mean pain = 5.3/10, SD = 1.4). Measures used included questionnaires assessing pain and negative affect, phasic thermal TS at the hand (thenar) and the lower back (lumbar), followed by CPM that included a thermal testing stimulus (Heat-6, the temperature where pain rating is 6/10) and a cold-pressor conditioning stimulus. Nonparametric, proportional odds logistic regression was used to model thenar, and separately, lumbar TS, using CPM, Heat-6, negative affect, and demographics.

Results

Our models revealed a small association (βs = 0.17, P = 0.01) between reduced CPM and heightened TS at both testing sites, regardless of demographics or negative affect.

Conclusion

Results suggest a modest association between TS and CPM, irrespective of anatomical testing location, demographics, and negative affect. These findings will help improve the methodology and interpretation of TS and CPM measurement in clinical pain populations.

The beneficial effect of physical activity on cognitive function in community-dwelling older persons with locomotive syndrome

Background

Cognitive decline is closely related to motor decline. Locomotive syndrome (LS) is defined as a state associated with a high risk of requiring support because of locomotive organ disorders, and can be evaluated using a questionnaire. This study aimed to clarify the effectiveness of daily goal-targeted exercise on cognitive function in two different populations classified by scores on the Locomo 25 questionnaire.

Methods

Seventy community-dwelling older people who participated in a 13-week health class were divided into two populations based on Locomo 25 scores: <7 (non-LS) and ≥7 (LS). Participants were presented with a daily target steps and worked towards that goal. Cognitive function was evaluated using the Japanese version of Addenbrooke’s Cognitive Examination-Revised (ACE-R). Average daily physical activity (exercise [Ex]) for 13 weeks was measured using a portable activity meter. Depression status was assessed using the Geriatric Depression Scale (GDS-15).

Results

No significant differences were observed in age, years of education, body mass index, smooth muscle mass index, GDS-15 scores, or ACE-R scores between the non-LS and LS populations. Multiple logistic regression analysis showed that Ex (odds ratio = 5.01, p = 0.002) for 13 weeks was significantly associated with increased cognitive function in the LS population. The Ex threshold for the increase in cognitive function based on receiver operating curve analysis was 2.29 metabolic equivalents of task (METs) × h (METs · h/day) (p = 0.047) in the LS population. After 13 weeks, ACE-R scores were significantly higher in the Ex ≥ 2.29 than in the Ex < 2.29 METs · h/day group (p = 0.024, η_p² = 0.241) in the LS population based on two-way analysis of covariance. Furthermore, a significant increase in the ACE-R memory domain was seen in the Ex ≥ 2.29 group (p = 0.035, η_p² = 0.213).

Conclusions

These results suggest that Ex ≥ 2.29 METs · h/day is important for improving cognitive function in LS populations.

Physical activity behavior in the first month after mild traumatic brain injury is associated with physiological and psychological risk factors for chronic pain

OBJECTIVE

The purpose of this study was to determine whether self-reported physical activity (PA) in the first month after mild traumatic brain injury (mTBI) predicts endogenous pain modulatory function and pain catastrophizing at 1 to 2 weeks and 1 month after injury in patients with mTBI.

METHODS

Patients with mild traumatic brain injury completed study sessions at 1 to 2 weeks and 1 month after injury. Assessments included a headache survey, Pain Catastrophizing Scale, International Physical Activity Questionnaire-Short Form, and several quantitative sensory tests to measure endogenous pain modulatory function including conditioned pain modulation (CPM), temporal summation, and pressure pain thresholds of the head. Hierarchical linear regressions determined the relationship between the PA variables (predictors) and pain catastrophizing and pain modulation variables (dependent variables) cross-sectionally and longitudinally, while controlling for potential covariates.

RESULTS

In separate hierarchical regression models, moderate PA, walking, and total PA at 1 to 2 weeks after injury predicted pain inhibition on the CPM test at 1 month, after controlling for significant covariates. In addition, a separate regression revealed that minutes sitting at 1 month predicted CPM at 1 month. Regarding predicting pain catastrophizing, the regression results showed that sitting at 1 to 2 weeks after injury significantly predicted pain catastrophizing at 1 month after injury.

CONCLUSION

Greater self-reported PA, especially moderate PA, 1 to 2 weeks after injury longitudinally predicted greater pain inhibitory capacity on the CPM test at 1 month after injury in patients with mTBI. In addition, greater sedentary behavior was associated with worse pain inhibition on the CPM test and greater pain catastrophizing at 1 month after injury.

Are Cardiometabolic Markers of Allostatic Load Associated With Pronociceptive Processes in Native Americans?: A Structural Equation Modeling Analysis From the Oklahoma Study of Native American Pain Risk

Native Americans (NAs) experience higher rates of chronic pain than the general U.S. population, but the risk factors for this pain disparity are unknown. NAs also experience high rates of stressors and cardiovascular and metabolic health disparities (eg, diabetes, cardiovascular disease) consistent with allostatic load (stress-related wear-and-tear on homeostatic systems). Given that allostatic load is associated with chronic pain, then allostatic load may contribute to their pain disparity. Data from 302 healthy, pain-free men and women (153 NAs, 149 non-Hispanic Whites [NHW]) were analyzed using structural equation modeling to determine whether cardiometabolic allostatic load (body mass index, blood pressure, heart rate variability) mediated the relationship between NA ethnicity and experimental measures of pronociceptive processes: temporal summation of pain (TS-pain) and the nociceptive flexion reflex (TS-NFR), conditioned pain modulation of pain (CPM-pain) and NFR (CPM-NFR), and pain tolerance. Results indicated that NAs experienced greater cardiometabolic allostatic load that was related to enhanced TS-NFR and impaired CPM-NFR. Cardiometabolic allostatic load was unrelated to measures of pain perception (CPM-pain, TS-pain, pain sensitivity). This suggests cardiometabolic allostatic load may promote spinal sensitization in healthy NAs, that is not concomitant with pain sensitization, perhaps representing a unique pain risk phenotype in NAs. PERSPECTIVE: Healthy, pain-free Native Americans experienced greater cardiometabolic allostatic load that was associated with a pronociceptive pain phenotype indicative of latent spinal sensitization (ie, spinal sensitization not associated with hyperalgesia). This latent spinal sensitization could represent a pain risk phenotype for this population.

A novel computational technique for the quantification of temporal summation in healthy individuals

BACKGROUND

The pathophysiology of chronic musculoskeletal pain is linked to the neurophysiologic condition known as central sensitization. Developing reliable, sensitive and clinically feasible techniques for quantifying central sensitization is a timely priority for advancing the field of chronic pain diagnosis and management.

OBJECTIVE

To compare the sensitivity of the Windup Ratio, a commonly employed Quantitative Sensory Testing (QST) technique, to a novel approach, the Sumsquare method, for detecting changes in experimentally induced central sensitization.

DESIGN

Individual, randomized, controlled experimental study.

METHODS

A total of 37 subjects assigned to experimental (N = 18) and control (N = 19) groups. Central sensitization was experimentally induced in the C5-C6 spinal segments using topical capsaicin (0.075%); controls received a non-sensitizing placebo (Lubriderm). Windup (temporal summation) was assessed using weighted pinpricks (MRC Systems, Heidelberg, Germany) applied within regions of secondary hyperalgesia surrounding the topical capsaicin. A train of 10 stimuli was applied at baseline, 10, 20 and 30 min post-topical application and participants provided numeric pain ratings after each pinprick application. Sumsquare and Windup Ratio outcomes were calculated using the pain rating data.

RESULTS

Sumsquare outcome was significantly increased at all time points (10, 20, 30 min) post-sensitization (p < 0.05); in contrast, no differences in Windup Ratio from baseline were observed at any time point post-sensitization (p > 0.05).

CONCLUSIONS

Sumsquare outcome offers greater sensitivity than Windup Ratio for detecting changes in experimentally induced central sensitization. These findings introduce a novel method for assessing changes in central sensitization in patients presenting with chronic musculoskeletal pain hypersensitivity.

Correlation Between Gut Microbiome Composition and Acute Pain Perception in Young Healthy Male Subjects

OBJECTIVE

Recently, there has been growing interest in the gut-brain axis because it is emerging as a player influencing the health status of the host human. It is a known fact that the gut microbiome (GM) through the gut-brain axis has been implicated in numerous diseases. We previously reported that stool condition was associated with pain perception. Stool consistency and constipation are known to be associated with GM composition. Thus, we imagine that GM composition could influence pain perception. The aim of this study was to investigate the correlations between GM composition and pain perception and psychological states in young healthy male subjects.

SUBJECTS

A total of 42 healthy young male volunteers completed the present study.

METHODS

The volunteers' pain perceptions were assessed by pressure pain threshold, current perception threshold, temporal summation of pain, and conditioned pain modulation, and a questionnaire on psychological state was obtained. During the current perception threshold examination, we used 5, 250, and 2,000 Hz to stimulate C, Aδ, and Aβ fibers. In addition, GM composition was evaluated by using 16S rRNA analysis.

RESULTS

Pressure pain threshold showed a significant and negative correlation with Bacteroidetes phylum, in contrast to a significant and positive correlation with Firmicutes phylum. Current perception threshold of Aδ and Firmicutes phylum showed a significant correlation. There was a negative correlation between anxiety state and Bifidobacterium genus. In contrast, there was no significant correlation between psychological states and pain perceptions.

CONCLUSION

The present study showed that acute pain perception was associated with GM composition in young healthy males.

Fibromyalgia in Older Individuals

Fibromyalgia (FM) is a condition of chronic widespread pain (CWP) that can occur throughout the life cycle and is likely underrecognized in older patients. FM is associated with considerable suffering and reduction in quality of life and may occur as a unique condition, but in older patients is most likely to be associated with another medical illness. Understood mechanistically to be a sensitization of the nervous system, recently identified as nociplastic pain, FM is accepted as a valid medical illness that requires a positive diagnosis and directed treatments. The cornerstone of treatments for FM are nonpharmacologic interventions, with the understanding that medications provide only modest benefit for most patients, and with particular concern about adverse effects in older patients. If FM is not recognized, treatments may be misdirected to the other medical condition, with failure to address FM symptoms, leading to overall poor outcome. In contrast, new complaints in older patients should not immediately be attributed to FM, and physicians should be vigilant to ensure that onset of a new illness is not ignored. As FM is most often a lifelong condition, patients should be encouraged to identify their own personal strategies that can attenuate symptoms, especially when symptoms flare. Continued life participation should be the outcome goal.

Regular swimming exercise prevented the acute and persistent mechanical muscle hyperalgesia by modulation of macrophages phenotypes and inflammatory cytokines via PPARγ receptors

Physically active individuals are less likely to develop chronic pain, and physical exercise is an established strategy to control inflammatory diseases. Here, we hypothesized that 1) peripheral pro-inflammatory macrophages phenotype contribute to predisposition of the musculoskeletal to chronic pain, and that 2) activation of PPARγ receptors, modulation of macrophage phenotypes and cytokines through physical exercise would prevent persistent muscle pain. We tested these hypotheses using swimming exercise, pharmacological and immunochemical techniques in a rodent model of persistent muscle hyperalgesia. Swimming prevented the persistent mechanical muscle hyperalgesia most likely through activation of PPARγ receptors, as well as activation of PPARγ receptors by 15d-PGJ₂ and depletion of muscle macrophages in sedentary animals. Acute and persistent muscle hyperalgesia were characterized by an increase in pro-inflammatory macrophages phenotype, and swimming and the 15d-PGJ₂ prevented this increase and increased anti-inflammatory macrophages phenotype. Finally, IL-1β concentration in muscle increased in the acute phase, which was also prevented by PPARγ receptors activation through swimming. Besides, swimming increased muscle concentration of IL-10 in both acute and chronic phases, but only in the persistent phase through PPARγ receptors. Our findings suggest physical exercise activates PPARγ receptors and increases anti-inflammatory responses in the muscle tissue by modulating macrophages phenotypes and cytokines, thereby preventing the establishment of persistent muscle hyperalgesia. These results further highlight the potential of physical exercise to prevent chronic muscle pain.