Musculoskeletal pain is associated with restless legs syndrome in young adults

Long latency trigemino-cervical reflex in restless legs syndrome

OBJECTIVE

The trigemino-cervical complex (TCC) seems under dopaminergic inhibitory control and the abnormalities of trigemino-cervical reflex (TCR) have been reported in disorders associated with the dopaminergic system and various pain disorders. If the inhibitory response in TCC is likely dopaminergic, we hypothesized that TCR, which has never been evaluated in restless legs syndrome (RLS) patients before, would be also abnormal.

METHODS

TCR was recorded from bilateral sternocleidomastoid and splenius capitis muscles in consecutive 15 drug-naive RLS patients and 16 age- and sex-matched healthy subjects. The right and left infraorbital branches of the trigeminal nerve were stimulated by percutaneous electrical stimulation separately. The presence rates, onset latencies, amplitudes, and durations of responses were measured and compared between patients with RLS and controls.

RESULTS

The presence rates, onset latencies and amplitudes of TCR responses were similar between RLS patients and controls, however, the durations of responses were bilaterally longer in RLS patients compared to healthy volunteers.

CONCLUSIONS

Hyperexcitability of TCR suggests defective sensory processing in the brainstem probably due to impairment of descending inhibitory dopaminergic system in RLS. The sensitization of TCC in RLS patients may also be a possible factor that might explain the association of RLS and pain disorders.

Prevalence of fibromyalgia among university students and its impact on their health-related quality of life: a survey-based study from Egypt

BACKGROUND

University students are more likely to experience stress, anxiety, and depression. All these factors are regarded as psychological contributors to fibromyalgia syndrome (FMS).

AIM

To investigate the prevalence and determinants of FMS among university students and its impact on their health-related quality of life (HRQoL).

METHODS

This online survey-based study involved 2146 university students who were recruited from various faculties at several Egyptian universities. The participants' demographics, medical history, academic pursuits, and sleep data were collected. To identify the existence of FMS, the 2016 updates to the 2010/2011 FMS diagnostic criteria were used. Additionally, the participants completed the Short-Form Health Survey-36 (SF-36).

RESULTS

The mean age was 21.26 ± 2.015 years and 76% were females. Of 2146 students, 266 (12.4%) fulfilled the criteria of FMS. FMS group had a significantly lower age (p < 0.001) with predominant female gender (89.5% vs. 74.1%, p < 0.001), positive family history of FMS (8.6% vs. 3.7%, p < 0.001), previous history of traffic accident (10.2% vs. 6.8%, p = 0.045), lower level of physical activity (p = 0.002),higher time spent in study per week (p = 0.002), lower sleep time (p = 0.002), with frequent walk up (p < 0.001) and snoring (p < 0.001) during sleep. Regarding HRQoL, students with FMS had significantly lower scores than students without in all domains.

CONCLUSION

FMS is prevalent among Egyptian university students and is linked to female gender, positive family history, lower levels of physical activity, and more time spent studying each week. FMS has a negative impact on HRQoL. Therefore, early detection and treatment are recommended.

Oxidative stress involves phenotype modulation of morbid soreness symptoms in fibromyalgia

OBJECTIVES

Muscle soreness occurs after exercise and also in musculoskeletal diseases, such as fibromyalgia (FM). However, the nosography and pathoetiology of morbid soreness in FM remain unknown. This study aimed to investigate the morbid soreness of FM, evaluate its therapeutic responses and probe its pathophysiology with metabolomics profiling.

METHODS

Patients with newly diagnosed FM were prospectively recruited and completed self-report questionnaires pertaining to musculoskeletal symptoms. The phenotypes and metabotypes were assessed with variance, classification and correlation analyses.

RESULTS

Fifty-one patients and 41 healthy controls were included. Soreness symptoms were prevalent in FM individuals (92.2%). In terms of manifestations and metabolomic features, phenotypes diverged between patients with mixed pain and soreness symptoms (FM-PS) and those with pain dominant symptoms. Conventional treatment for FM did not ameliorate soreness severity despite its efficacy on pain. Moreover, despite the salient therapeutic efficacy on pain relief in FM-PS cases, conventional treatment did not improve their general disease severity. Metabolomics analyses suggested oxidative metabolism dysregulation in FM, and high malondialdehyde level indicated excessive oxidative stress in FM individuals as compared with controls (p=0.009). Contrary to exercise-induced soreness, lactate levels were significantly lower in FM individuals than controls, especially in FM-PS. Moreover, FM-PS cases exclusively featured increased malondialdehyde level (p=0.008) and a correlative trend between malondialdehyde expression and soreness intensity (r=0.337, p=0.086).

CONCLUSIONS

Morbid soreness symptoms were prevalent in FM, with the presentation and therapeutic responses different from FM pain conditions. Oxidative stress rather than lactate accumulation involved phenotype modulation of the morbid soreness in FM.

TRIAL REGISTRATION NUMBER

NCT04832100.

Back Pain without Disease or Substantial Injury in Children and Adolescents: A Twin Family Study Investigating Genetic Influence and Associations

This twin family study first aimed to investigate the evidence for genetic factors predicting the risk of lifetime prevalence of non-specific low back pain of at least three months duration (LBP (life)) and one-month current prevalence of thoracolumbar back pain (TLBP (current)) using a study of children, adolescents, and their first-degree relatives. Secondly, the study aimed to identify associations between pain in the back with pain in other regions and also with other conditions of interest. Randomly selected families (n = 2479) with child or adolescent twin pairs and their biological parents and first siblings were approached by Twins Research Australia. There were 651 complete twin pairs aged 6-20 years (response 26%). Casewise concordance, correlation, and odds ratios were compared for monozygous (MZ) and dizygous (DZ) pairs to enable inference about the potential existence of genetic vulnerability. Multivariable random effects logistic regression was used to estimate associations between LBP (life) or TLBP (current) as an outcome with the potentially relevant condition as predictors. The MZ pairs were more similar than the DZ pairs for each of the back pain conditions (all p values < 0.02). Both back pain conditions were associated with pain in multiple sites and with primary pain and other conditions using the combined twin and sibling sample (n = 1382). Data were consistent with the existence of genetic influences on the pain measures under the equal environments assumption of the classic twin model and associations with both categories of back pain were consistent with primary pain conditions and syndromes of childhood and adolescence which has research and clinical implications.

Restless legs syndrome in patients with chronic low back pain

Background

Based on studies showing that both chronic low back pain (LBP) and restless legs syndrome (RLS) have similar pathophysiological mechanisms, we aimed to investigate the prevalence of RLS in patients with chronic LBP and to define which demographic and clinical features are prominent in those with LBP accompanied by RLS.

Methods

One hundred and two eligible, volunteer participants with chronic LBP were enrolled in this study. Visual analog scale (VAS), the Oswestry Disability Index (ODI), Pittsburgh Sleep Quality Index, Beck Depression Inventory, and Short Form-36 scales were applied to the patients. All patients were evaluated face-to-face for RLS using the International RLS study group diagnostic criteria.

Results

Most of our patients were women (52%). The mean age was 40.96±13.34 years and the mean disease duration was 46.16±41.98 months. RLS was detected in 36 (35.3%) of the patients with LBP. It was found that the female gender was more dominant in patients with RLS and the difference was statistically significant (p < 0.001). The amount of coffee intake was significantly higher in patients with RLS compared to those without RLS (p = 0.001). The disease duration for LBP was significantly higher in the patients with RLS (p = 0.003). VAS score, ODI score, PUKI score, and Beck depression score were significantly higher in the RLS group (p value were 0.048, 0.040, 0.007, and 0.043, respectively). In the evaluation of quality of life, all parameters except role emotional limitations and mental health were found to be significantly worse in the RLS group.

Mechanisms underlying acupuncture therapy in chronic kidney disease: A narrative overview of preclinical studies and clinical trials

Chronic kidney disease (CKD) is associated with high incidence, low awareness, and high disability rates among the population. Moreover, the disease significantly affects the physical and mental health of patients. Approximately 25% of patients with CKD develop end-stage renal disease (ESRD) within 20 years of diagnosis and have to rely on renal replacement therapy, which is associated with high mortality, heavy economic burden, and symptoms including fatigue, pain, insomnia, uremia pruritus, and restless leg syndrome. Currently, the means to delay the progress of CKD are insufficient; therefore, developing strategies for delaying CKD progression has important practical implications. In recent years, more and more people are accepting the traditional Chinese medical technique "acupuncture." Acupuncture has been shown to improve the uncomfortable symptoms of various diseases through stimulation (needling, medicinal moxibustion, infrared radiation, and acupressure) of acupoints. Its application has been known for thousands of years, and its safety and efficacy have been verified. As a convenient and inexpensive complementary therapy for CKD, acupuncture has recently been gaining interest among clinicians and scientists. Nevertheless, although clinical trials and meta-analysis findings have demonstrated the efficacy of acupuncture in reducing albuminuria, improving glomerular filtration rate, relieving symptoms, and improving the quality of life of patients with CKD, the underlying mechanisms involved are still not completely understood. Few studies explored the correlation between acupuncture and renal pathological diagnosis. The aim of this study was to conduct a literature review summarizing the currently known mechanisms by which acupuncture could delay the progress of CKD and improve symptoms in patients with ESRD. This review help provide a theoretical basis for further research regarding the influence of acupuncture on renal pathology in patients with CKD, as well as the differences between specific therapeutic mechanisms of acupuncture in different renal pathological diagnosis. The evidence in this review indicates that acupuncture may produce marked effects on blocking and reversing the critical risk factors of CKD progression (e.g., hyperglycemia, hypertension, hyperlipidemia, obesity, aging, and anemia) to improve the survival of patients with CKD via mechanisms including oxidative stress inhibition, reducing inflammatory effects, improving hemodynamics, maintaining podocyte structure, and increasing energy metabolism.

Cross-Sectional Design: Link Between Parkinson's Pain and Restless Leg Syndrome

OBJECTIVE

Prior research suggests that restless leg syndrome (RLS) is prevalent in Parkinson's disease (PD) with insufficient evidence to support the relationship between RLS, PD, and pain. This study explored the relationship between pain in PD patients and its association with the prevalence and severity of RLS.

METHOD

127 PD patients were assessed for PD and RLS using the U.K. Brain bank Criteria and the Restless Leg Syndrome diagnostic criteria, respectively. These patients were also assessed for pain perception and interference using the Brief Pain Inventory.

RESULTS

The results demonstrated Parkinson's disease patients who reported pain scored 23 more Restless Leg Syndrome prevalence points (p < 0.05), and 8.5 counts higher for Restless Leg Syndrome severity (p < 0.05) compared to the group of Parkinson's disease patients denying pain.

DISCUSSION

The presence of pain in PD patients indicated a higher RLS prevalence and an increased RLS severity. This finding suggests patients suffering from pain interference may experience more severe RLS symptoms. This demonstrates an inextricable link and association between pain in PD patients and RLS. Further robust investigations are required to elucidate any potential causative links, which can inform more holistic treatment principles.

Influence of increased pain sensitivity on patient-reported outcomes following total knee arthroplasty

PURPOSE

The purpose of this study was to discover whether increased pain sensitivity was associated with postoperative pain and patient-reported outcome measures (PROMs) after total knee arthroplasty (TKA).

METHODS

Pain sensitivity was evaluated preoperatively using a pain sensitivity questionnaire (PSQ). Resting, walking, nighttime, and average pain visual analog scale (VAS) were measured before surgery and 6 weeks, 3 months, 6 months, and 1 year after surgery. PROMs were also evaluated based on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score and patient satisfaction. The association between pain VAS average score, WOMAC total score, and PSQ score (minor, moderate, and total score) was assessed at each stage.

RESULTS

There were 59 patients with a high PSQ score (≥ 5.2) and 53 with a low PSQ score (< 5.2). Up to 1 year postoperatively, the group with high PSQ scores had higher resting, walking, nighttime, and average pain VAS scores than the group with low scores (all p < 0.05). Worse preoperative WOMAC pain, function, and total scores continued until 1 year after surgery in the high-scoring PSQ group (all p < 0.05). The group with low PSQ scores was more satisfied with surgery than the group with high scores (p = 0.027). There was a positive correlation between preoperative PSQ score and pain VAS average score at all time points (all p < 0.05). A relationship between PSQ score and WOMAC total score was also observed (all p < 0.05).

CONCLUSION

Increased pain sensitivity is a factor related to higher postoperative pain levels and inferior PROMs in patients undergoing primary TKA.

LEVEL OF EVIDENCE

Case-controlled study, III.

The prevalence of chronic pain in young adults: a systematic review and meta-analysis

ABSTRACT

Prior systematic reviews have summarized the prevalence and impact of chronic pain in "average" pediatric (i.e., school-age) and adult (i.e., middle-age) age groups. To our knowledge, this is the first study to describe the prevalence of chronic pain in the subgroup of individuals that fall in between established boundaries of "childhood" and "adulthood" - known as young adulthood. The goal of this research was to meta-analyze prevalence data on pain in young adults based on available data published between 2008 and 2020. Searches were identified with MEDLINE, Embase, and PsycINFO. We included general population and university-based studies presenting prevalence estimates of chronic pain (pain lasting ≥3 months) in young adults. We identified 43 articles providing prevalence estimates across a combined population of 97,437 young adult respondents (age range: 15-34), with studies undertaken in 22 countries. Available data allowed for stratification of prevalence according to pain condition. The overall pooled random-effect prevalence rate of chronic pain in young adults was 11.6%, suggesting that 1 in every 9 young adults experience chronic pain worldwide. Prevalence rates varied considerably according to pain condition. Estimates did not vary according to sex, geographic location, and several study methodological characteristics (i.e., population type, sampling area, sampling year, investigation period, assessment method). Overall, young adult chronic pain is common and should be recognized as a major public health concern. Considering the difficulties young adults face accessing adult healthcare, greater attention is needed to develop transition programs and evidence-based treatments tailored to the unique needs of this age group.

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

Background

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

Methods

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

Results

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

Conclusions

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

The effect of long-term poor sleep quality on risk of back-related disability and the modifying role of physical activity

Sleep problems and regular leisure time physical activity (LTPA) are interrelated and have contrasting effects on risk of back pain. However, no studies have investigated the influence of long-term poor sleep quality on risk of back-related disability, or if LTPA modifies this association. The study comprised data on 8601 people who participated in three consecutive surveys over ~ 22 years, and who reported no chronic back pain at the two first surveys. Adjusted risk ratios (RRs) for back-related disability were calculated at the last survey, associated with the joint effect of changes in sleep quality between the two first surveys and meeting physical activity guidelines at the second survey. Compared to people with long-term good sleep, people with long-term poor sleep had nearly twice the risk of back-related disability (RR 1.92, 95% CI 1.48-2.49). There was no statistical interaction between sleep and LTPA but people who reported long-term poor sleep and meeting the physical activity guidelines had 35% lower risk of back-related disability compared to people with same level of sleep problems, but who not met the guidelines. These findings suggest that long-term poor sleep quality contributes to a substantially increased risk of chronic and disabling back pain irrespective of LTPA.

Long-term changes in self-reported sleep quality and risk of chronic musculoskeletal pain: The HUNT Study

We examined the association between long-term (~10 years) changes in self-reported sleep quality and risk of any chronic musculoskeletal pain and chronic widespread pain. The study comprised data on 6,033 people who participated in three consecutive surveys in the Norwegian HUNT Study (1995-1997, 2006-2008 and 2017-2019) and who were without chronic musculoskeletal pain at the first two surveys. We used a modified Poisson regression model to calculate adjusted risk ratios for chronic pain at follow-up (2017-2019) associated with categories of poor and good sleep quality reported in 1995-1997 and 2006-2008. Compared with people who reported good sleep at both surveys (crude absolute risk: 32.4%), the risk ratios of any chronic pain were 1.20 (95% confidence interval: 1.02-1.41) for those who changed from poor to good sleep; 1.25 (95% confidence interval: 1.12-1.39) for those who changed from good to poor sleep; and 1.41 (95% confidence interval: 1.21-1.63) for those who reported long-term poor sleep. The corresponding risk ratios for chronic widespread pain were 1.35 (95% confidence interval: 0.82-2.23), 1.55 (95% confidence interval: 1.14-2.12) and 2.09 (95% confidence interval: 1.38-3.17), respectively. In conclusion, these findings indicate that people with long-term poor sleep quality have a markedly higher risk of chronic musculoskeletal pain and chronic widespread pain, compared with people who remain good sleep quality.

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

IMPACT

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

Sleep and restless legs syndrome in female adolescents with idiopathic musculoskeletal pain

OBJECTIVES

To assess the presence of restless legs syndrome, periodic leg movement, and sleep disorders in female adolescents with idiopathic musculoskeletal pain through a sleep scale and polysomnography, and to compare these data in adolescents without pain history.

METHOD

Twenty-six adolescents diagnosed with idiopathic musculoskeletal pain followed in a pain outpatient clinic and 25 healthy controls matched by age and education were recruited. The restless legs syndrome criteria were evaluated according to the International Restless Legs Syndrome Study Group, the Sleep Disturbance Scale for Children was completed, nocturnal polysomnography was performed, and anxiety symptoms were recorded.

RESULTS

The mean age of idiopathic musculoskeletal pain adolescents was 13.9±1.6 years; in controls, it was 14.4±1.4 years. One adolescent in the control group (4 %) and nine patients with idiopathic musculoskeletal pain (34.6 %) fulfilled the restless legs syndrome criteria (p=0.011). The authors did not observe significant differences in Sleep Disturbance Scale for Children scores between the groups in all components: disorders of initiating and maintaining sleep (p=0.290), sleep breathing disorders (p=0.576), disorders of arousal (p=0.162), sleep-wake transition disorders (p=0.258), disorder of excessive daytime somnolence (p=0.594), and sleep hyperhidrosis (p=0.797). The neurophysiological, respiratory, and periodic leg movement parameters were similar in both groups. Having anxiety was not associated with restless legs syndrome (p=0.11). Three patients with idiopathic musculoskeletal pain (11.5 %) presented restless legs syndrome and periodic leg movement simultaneously, which was absent in the control group.

CONCLUSION

Female adolescents with idiopathic musculoskeletal pain present criteria for RLS more frequently than healthy adolescents. However, this study did not observe relevant changes in objective and subject sleep variables.

(Neuro)Inflammatory Component May Be a Common Factor in Chronic Widespread Pain and Restless Legs Syndrome

Purpose of Review

Recent studies have linked fibromyalgia (nociplastic pain) and depression to neuroinflammation. Restless legs syndrome (RLS) is highly prevalent in CWP (chronic widespread pain) and FMS (fibromyalgia syndrome) as well as in depression. This review focuses on evidence in the relationship between CWP and RLS and possible common pathophysiological mechanisms.

Recent Findings

CWP is chronic pain spread over various locations of the body and is a cardinal sign of fibromyalgia. Poor sleep quality is a common symptom in fibromyalgia as well as high levels of fatigue, poor cognition, and other associated features which include depression, headache, and abdominal pain. Evidence for a bilateral relationship between pain and sleep deficit is robust. The latest research focus is not only on insomnia symptoms in chronic pain but also on other types of sleep disorders such as RLS which is characterized by complaints of an “urge to move” frequently associated with dysesthesias. These sensations can also have painful characteristics. Thus, there is a possible overlap between these two entities. The high prevalence of RLS (33–54%) in CWP has been shown in several studies. The pathophysiological mechanisms behind CWP and RLS are still not completely known, but there is a rising amount of evidence on proinflammatory and neuroinflammatory processes in CWP. In RLS, there are links to dopaminergic dysfunction and more generally to monoaminergic dysfunctional circuits, BID (brain iron deficiency), altered glutamatergic neurotransmission, and genetic traits. Depression is a common comorbidity as well in CWP as RLS, and proinflammatory mechanisms have also been demonstrated in this condition.

Summary

The association between CWP and RLS is shown to be high and the pathogenesis of both conditions is still not completely understood. Recent research is focusing on proinflammatory and neuroinflammatory processes, not uniquely emerging in fibromyalgia/CWP, but inflammatory features have been found in depression as well as in sleep deficit. Proinflammatory/neuroinflammatory processes may be an underlying, common factor in both CWP and RLS that future research should investigate further.

The influence of restless legs symptoms on musculoskeletal pain in depression

Background and aims Restless legs syndrome is a sensorimotor disorder associated with mental health conditions notably depression. Restless legs symptoms and depression are commonly associated with pain. The study investigated the influence of restless legs symptoms on musculoskeletal pain in patients with depression or with increased depressive symptoms. Methods A cross-sectional study of primary care patients in the Central Finland Hospital District. The prevalence of restless legs symptoms was studied in patients with depressive symptoms (n = 695) and controls without a psychiatric diagnosis (n = 410) by using a structured questionnaire. The depressive symptoms were evaluated with the Beck Depression Inventory and the psychiatric diagnosis was confirmed by means of a diagnostic interview (MINI). The prevalence and intensity of musculoskeletal pain was captured with form-based questions. A single-question screen for restless legs symptoms was applied. Results There was a significant difference in the prevalence of continuous widespread musculoskeletal pain between the three study groups: the controls 4.6% (95% CI: 2.8-7.1), the patients with symptoms of depression without a diagnosis 16.0% (11.7-21.1), and the patients with diagnosed depression 22.1% (18.3-23.3) (p = 0.006 after being adjusted for age, sex, smoking, use of alcohol, education years, body mass index, use of antidepressants, and physical activity, after multiple corrections, all groups were significantly different from each other). Compared with those not having restless legs symptoms, subjects with restless legs symptoms had more often continuous widespread musculoskeletal pain in the control subjects (p = 0.001; 2.3% vs. 10.5%) and in the patients with depressive symptoms without a depression diagnosis (p = 0.024; 9.1 vs. 18.7%) but not in those with diagnosed depression (p = 0.98; 19.5 vs. 19.4%). The restless legs symptoms were associated with the intensity of pain in all groups (p < 0.001). Conclusions Restless legs symptoms were related to continuous widespread musculoskeletal pain in subjects without depressive symptoms and in patients with depressive symptoms without a depression diagnosis. Pain intensity was higher in the subjects with restless legs symptoms regardless of depressive symtoms or depression. Implications Clinical management of pain in patients with restless legs symptoms should include an increased focus on the prevention and treatment of either conditions.

Number of Chronic Nighttime Insomnia Symptoms and Risk of Chronic Widespread Pain and Pain-Related Disability: The HUNT Study

STUDY OBJECTIVES

To examine the association between the number of chronic nighttime insomnia symptoms and the risk of chronic widespread pain (CWP) and pain-related disability.

METHODS

A prospective study of 10,847 participants in the Norwegian HUNT Study without chronic musculoskeletal pain at baseline in 2006-2008. We used a modified Poisson regression model to estimate adjusted risk ratios (RRs) with a 95% confidence interval (CI) for CWP and pain-related disability at follow-up in 2017-2019 associated with insomnia and number of nighttime insomnia symptoms at baseline. Chronic insomnia was defined according to the current classification system and grouped into three categories based on the number of reported nighttime symptoms (ie, difficulty initiating sleep, trouble maintaining sleep and early morning awakenings).

RESULTS

Compared to the reference group of people without insomnia, people with insomnia had RRs for CWP and pain-related disability of 1.64 (1.26-2.14) and 1.63 (1.37-1.94), respectively. When people with insomnia were categorized based on the number of nighttime symptoms, people who reported one, two, or three nighttime symptoms had RRs of CWP of 1.19 (95% CI 0.80-1.78), 1.78 (95 CI 1.13-2.80) and 3.08 (95% CI 1.93-4.92), respectively, compared to people without insomnia. The corresponding RRs for pain-related disability were 1.49 (95% CI 1.17-1.89), 1.46 (95% CI 2.04-2.05), and 2.46 (95% CI 1.76-3.42).

CONCLUSION

These findings indicate that people with insomnia characterized by symptoms in all phases of the sleep period have a substantially increased risk of CWP and pain-related disability.

Chronic Widespread Pain and Fibromyalgia Syndrome: Life-Course Risk Markers in Young People

Although the life-course concept of risk markers as potential etiological influences is well established in epidemiology, it has not featured in academic publications or clinical practice in the context of chronic widespread pain (CWP) and fibromyalgia syndrome (FMS). Studies of risk markers are required considerations for evaluation of patients and for research because there is no single cause, pathological feature, laboratory finding, or biomarker for CWP or FMS. The early-life risk markers identified by extensive literature review with best evidence for potential causal influence on the development and progression of CWP and FMS include genetic factors, premature birth, female sex, early childhood adversity, cognitive and psychosocial influences, impaired sleep, primary pain disorders, multiregional pain, physical trauma, infectious illness, obesity and inactivity, hypermobility of joints, iron deficiency, and small-fiber polyneuropathy. The case history illustrates the potential etiological influence of multiple risk markers offset by personal resilience.

Are serum ferritin and transferrin saturation risk markers for restless legs syndrome in young adults? Longitudinal and cross-sectional data from the Western Australian Pregnancy Cohort (Raine) Study

Restless legs syndrome has been associated with serum iron deficiency in clinical studies. However, studies investigating this relationship have had inconsistent results and there are no studies in young adults. Therefore, we investigated the relationship between serum measures of iron stores and restless legs syndrome in young adults in the community. Participants in the Western Australian Pregnancy Cohort (Raine) Study answered questions on restless legs syndrome (n = 1,100, 54% female) at age 22 years, and provided serum measures of iron stores (ferritin and transferrin saturation) at ages 17 and 22 years. Restless legs syndrome was diagnosed when four International RLS Study Group criteria were met (urge to move, dysaesthesia, relief by movement, worsening during evening/night) and these symptoms occurred ≥5 times per month. Logistic regression was used to assess associations between serum iron stores and restless legs syndrome, adjusting for potential confounders. The prevalence of restless legs syndrome at age 22 years was 3.0% (n = 33, 70% female). Among those who provided restless legs syndrome and iron data at age 22 years (n = 865), the median (interquartile range) ferritin was not different between the restless legs syndrome (55 [29.5-103.5] µg L^-1 ) and the non-restless legs syndrome group (65.0 [35.0-103.3] µg L^-1 , p = 0.2), nor were there differences in iron deficiency prevalence (p = 0.36). There was no association between restless legs syndrome (22 years) and iron stores (17, 22 years) before or after adjustment for potential confounders. There was no association between restless legs syndrome at 22 years and iron stores at 17 or 22 years in this cohort. Serum iron stores may not be a useful indicator of restless legs syndrome risk in young adults in the community.

Effect of Near-Infrared Light Therapy Based on Acupoints on the Severity of Restless Legs Syndrome in Patients Undergoing Hemodialysis: A Single-Blind, Randomized Controlled Trial

INTRODUCTION

Restless legs syndrome (RLS) is a common disorder in hemodialysis patients. The present study was conducted to determine the effect of near-infrared (NIR) light therapy given to acupoints on the severity of RLS in patients undergoing hemodialysis.

METHODS

This single-blind, randomized controlled trial was performed on 60 hemodialysis patients with RLS. Participants who met the inclusion criteria were randomly assigned to an intervention group (n = 30) or a control group (n = 30). Data were collected using the International Restless Legs Syndrome Rating Scale (IRLSRS) and demographic information questionnaire. The intervention group received 12 sessions of NIR light therapy (940 nm) to acupoints in the legs and feet during hemodialysis three times a week, while the control group received sham treatment. Data were analyzed using SPSS version 22 software.

RESULTS

The results indicated that there were statistically and clinically significant differences between the intervention and control groups at the end of the intervention sessions (P < 0.001, mean difference [MD] = 3.8). However, after the treatment was discontinued, the difference was not clinically significant (MD = 2.4). In the within-group compression, the mean RLS scores of the intervention group decreased significantly during the intervention sessions (MD = 3.2, P < 0.001); however, after the treatment was discontinued, the difference was not clinically significant (MD = 1.67).

CONCLUSION

The present study showed that the application of NIR light to acupoints in the legs and feet was as an effective treatment for attenuating the symptoms of RLS in hemodialysis patients.

Effectiveness of fixed-site high-frequency transcutaneous electrical nerve stimulation in chronic pain: a large-scale, observational study

Objective

The objective of this study was to assess the effectiveness of fixed-site high-frequency transcutaneous electrical nerve stimulation (FS-TENS) in a real-world chronic pain sample.

Background

There is a need for nonpharmacological treatment options for chronic pain. FS-TENS improved multisite chronic pain in a previous interventional study. Large observational studies are needed to further characterize its effectiveness.

Methods

This retrospective observational cohort study examined changes in chronic pain measures following 60 days of FS-TENS use. The study data were obtained from FS-TENS users who uploaded their device utilization and clinical data to an online database. The primary outcome measures were changes in pain intensity and pain interference with sleep, activity, and mood on an 11-point numerical rating scale. Dose-response associations were evaluated by stratifying subjects into low (≤30 days), intermediate (31-56 days), and high (≥57 days) utilization subgroups. FS-TENS effectiveness was quantified by baseline to follow-up group differences and a responder analysis (≥30% improvement in pain intensity or ≥2-point improvement in pain interference domains).

Results

Utilization and clinical data were collected from 11,900 people using FS-TENS for chronic pain, with 713 device users meeting the inclusion and exclusion criteria. Study subjects were generally older, overweight adults. Subjects reported multisite pain with a mean of 4.8 (standard deviation [SD] 2.5) pain sites. A total of 97.2% of subjects identified low back and/or lower extremity pain, and 72.9% of subjects reported upper body pain. All pain measures exhibited statistically significant group differences from baseline to 60-day follow-up. The largest changes were pain interference with activity (-0.99±2.69 points) and mood (-1.02±2.78 points). A total of 48.7% of subjects exhibited a clinically meaningful reduction in pain interference with activity or mood. This proportion increased to 57.1% for the high utilization subgroup.

Conclusion

FS-TENS is a practical option for treating multisite chronic pain. The greatest impact is on pain interference with activity and mood. FS-TENS utilization and effectiveness exhibit a dose-response association, suggesting that daily use maximizes pain relief.

Morning cortisol and fasting glucose are elevated in women with chronic widespread pain independent of comorbid restless legs syndrome

Background and aims:

Chronic widespread pain (CWP) is associated with poor quality of sleep, but the detailed underlying mechanisms are still not fully understood. In this study we investigated the influence of CWP on morning cortisol and fasting glucose concentrations as well as sleep disordered breathing.

Methods:

In this case-control study, subjects with CWP (n=31) and a control group without CWP (n=23) were randomly selected from a population-based cohort of women. Current pain intensity, sleep quality, excessive daytime sleepiness [Epworth sleepiness scale (ESS)], psychiatric comorbidity and occurrence of restless legs syndrome (RLS) were assessed. Overnight polygraphy was applied to quantify sleep apnoea, airflow limitation and attenuations of finger pulse wave amplitude (>50%) as a surrogate marker for increased skin sympathetic activity. Morning cortisol and fasting glucose concentrations were determined. Generalised linear models were used for multivariate analyses.

Results:

CWP was associated with higher cortisol (464±141 vs. 366±111 nmol/L, p=0.011) and fasting glucose (6.0±0.8 vs. 5.4±0.7 mmol/L, p=0.007) compared with controls. The significance remained after adjustment for age, body mass index, RLS and anxiety status (β=122±47 nmol/L and 0.89±0.28 mmol/L, p=0.009 and 0.001, respectively). The duration of flow limitation in sleep was longer (35±22 vs. 21±34 min, p=0.022), and pulse wave attenuation was more frequent (11±8 vs. 6±2 events/h, p=0.048) in CWP subjects compared with controls. RLS was associated with higher ESS independent of CWP (β=3.1±1.3, p=0.018).

Conclusions:

Elevated morning cortisol, impaired fasting glucose concentration and increased skin sympathetic activity during sleep suggested an activated adrenal medullary system in subjects with CWP, which was not influenced by comorbid RLS.

Implications:

CWP is associated with activated stress markers that may deteriorate sleep.

Causal Mediation in the Development of Painful Temporomandibular Disorder

We explored causal mediation of sleep quality and perceived stress in development of painful temporomandibular disorder (TMD). Sleep quality and perceived stress were assessed at baseline and quarterly intervals thereafter in 2,737 initially TMD-free adults in the Orofacial Pain Prospective Evaluation and Risk Assessment study (OPPERA) prospective cohort study. During follow-up, incident TMD cases were classified using research diagnostic criteria. Mediation analysis was conducted using a weighted Cox proportional hazards regression model that estimated hazard ratios (HRs) and 95% confidence limits (CL) of first-onset TMD. Models determined whether: 1) poor sleep quality during follow-up mediated the effect of baseline perceived stress on first-onset TMD, and 2) perceived stress during follow-up mediated the effect of baseline poor sleep quality on first-onset TMD. In both analyses, the total effect was decomposed into natural direct and indirect effects. Poor baseline sleep quality led to heightened perceived stress that then contributed to TMD development. When the total effect of poor sleep quality (HR = 2.10, CL = 1.76, 2.50) was decomposed, 34% of its effect was mediated by perceived stress (indirect effect HR = 1.29, CL = 1.06, 1.58). The effect of perceived stress on first-onset TMD was not mediated by sleep quality. Improving sleep may avert escalation of stress, limiting effects of both factors on TMD development.

PERSPECTIVE

Causal mediation analysis highlights mechanisms by which poor sleep quality promotes development of TMD. First, poor sleep quality exerts a direct effect on pain. Second, it triggers a heightened perception of stress, which acts as an intermediate factor in the causal pathway between poor sleep quality and first-onset TMD pain.