The relationship of obesity, age, and carpal tunnel syndrome: more complex than was thought?

Waist circumference and waist-to-hip ratio in carpal tunnel syndrome: a case-control study

BACKGROUND

The association between carpal tunnel syndrome (CTS) and high body mass index (BMI) and some hand measures is well known. No study has been specifically focused on waist circumference (WC) and waist-to-hip-ratio (WHR). The aim of this prospective case-control study is to evaluate the association between CTS and WC, WHR and other body and hand anthropometric measures.

METHODS

We consecutively enrolled one "idiopathic" CTS case for two controls in 3 outpatient electromyography labs. The main anthropometric measures were BMI, WC, WHR, wrist ratio (WR) and hand ratio (HR). We performed univariate and multivariate analyses.

RESULTS

Female cases and controls were 250 and 474 and male cases and controls were 120 and 273, respectively. At univariate analysis there were differences in many anthropometric measures between cases and controls. At multivariate logistic regression analyses high BMI, WC and WHR and abnormal HR and WR were independent risk factors for CTS. Crossing two categories between BMI, WC and WHR, the overweight subjects, especially females, were at risk only if they had very high WC or high WHR. The risk increased if they were obese.

CONCLUSIONS

High WC/WHR doubles the risk of CTS, the risk further increased if overweight/obese subjects have also very high WC or high WHR. The obese subjects were always at risk regardless of WC and WHR values. Metabolic causes of this association with CTS were hypothesised. BMI is not the only and most powerful body predictor of "idiopathic" CTS, but also WHR and WC should be considered. These measures may not be interchangeable and it may be desirable to consider the utility of their joint use.

Relationship of age, body mass index, wrist and waist circumferences to carpal tunnel syndrome severity

Carpal tunnel syndrome (CTS) has a multifactorial etiology involving systemic, anatomical, idiopathic, and ergonomic characteristics. In this study, an investigation of the relationship between the CTS degree established by electrophysiological measurements in patients with clinical CTS prediagnosis, and age, gender, body mass index (BMI), hand wrist circumference, and waist circumference measurements has been done. On 547 patients included in the study, motor and sensory conduction examinations of the median and ulnar nerve were done on one or two upper extremities thought to have CTS. In terms of CTS severity, the patients were divided into four groups (normal, mild, medium, and severe CTS). A total of 843 electrophysiological examinations were done consisting of 424 on the right hand wrist and 419 on the left hand wrist. When the age group of 18–35 years is taken as the reference group, the CTS development risk independent of BMI has been found to have increased by a factor of 1.86 for ages 36–64 years, and by 4.17 for ages 65 years and higher after adjustment for BMI. With respect to normal degree CTS group, the BMI were significantly different in groups with mild, medium, and severe CTS. The waist circumferences of groups with mild, medium, and severe CTS severity were found to be significantly higher in comparison to the normal reference group. When this value was corrected with BMI and re-examined the statistically significant differences persisted. The study identified a significant relationship between the CTS severity and age, BMI, waist circumference.

Carotid intima-media thickness in patients with carpal tunnel syndrome

OBJECTIVES

We measured the carotid intima-media thickness, a surrogate marker of early atherosclerosis, in patients with carpal tunnel syndrome compared to a control group to evaluate the risk of atherosclerotic disease.

METHODS

Between January 2011 and December 2011, female patients presenting to the outpatient neurology clinic for pain and paresthesia in the hands were screened for study enrollment. Patients 30 years or older were eligible for the study if they did not have a history of stroke or cardiovascular disease.

RESULTS

During the study period, 111 patients (58 in the carpal tunnel syndrome group and 53 in the control group) were enrolled, with a mean age of 56 years (range, 32-79 years). There were no significant differences in baseline characteristics except maximum carotid intima-media thickness and body mass index. The maximum intima-media thickness was greater in the carpal tunnel syndrome group (mean ± SD, 1.05 ± 0.17 mm) than the control group (0.85 ± 0.22 mm; P < .0001). The body mass index was greater among the controls (P = .012). Simple linear regression analysis revealed that age (P < .0001), carpal tunnel syndrome (P < .0001), hypertension (P = .022), and systolic blood pressure (P = .034) were statistically significantly associated with increased intima-media thickness. Multiple linear regression analysis revealed that hypertension (P = .033), systolic blood pressure (P = .022), age (P < .0001), and carpal tunnel syndrome (P < .0001) were significantly associated with increased intima-media thickness, with carpal tunnel syndrome being the most influential factor (β = 0.489).

CONCLUSIONS

The maximum carotid intima-media thickness was significantly increased in patients with carpal tunnel syndrome compared to controls. Chronic inflammation beyond the traditional cardiovascular risk factors might be related to increased carotid intima-media thickness in patients with carpal tunnel syndrome.

Evaluation and treatment of upper extremity nerve entrapment syndromes

Nerve entrapment syndromes in the upper extremity are being recognized with increasing frequency. Prompt and correct diagnosis of these injuries is important. This article is a review of the common entrapment nerve injuries seen in the upper extremity. Each of these clinical syndromes is discussed independently, reviewing the anatomy, compression sites, patient presentation (history and examination), the role of additional diagnostic studies, and management.

Differences in risk factors for neurophysiologically confirmed carpal tunnel syndrome and illness with similar symptoms but normal median nerve function: a case-control study

BACKGROUND

To explore whether risk factors for neurophysiologically confirmed carpal tunnel syndrome (CTS) differ from those for sensory symptoms with normal median nerve conduction, and to test the validity and practical utility of a proposed definition for impaired median nerve conduction, we carried out a case-control study of patients referred for investigation of suspected CTS.

METHODS

We compared 475 patients with neurophysiological abnormality (NP+ve) according to the definition, 409 patients investigated for CTS but classed as negative on neurophysiological testing (NP-ve), and 799 controls. Exposures to risk factors were ascertained by self-administered questionnaire. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were estimated by logistic regression.

RESULTS

NP+ve disease was associated with obesity, use of vibratory tools, repetitive movement of the wrist or fingers, poor mental health and workplace psychosocial stressors. NP-ve illness was also related to poor mental health and occupational psychosocial stressors, but differed from NP+ve disease in showing associations also with prolonged use of computer keyboards and tendency to somatise, and no relation to obesity. In direct comparison of NP+ve and NP-ve patients (the latter being taken as the reference category), the most notable differences were for obesity (OR 2.7, 95 % CI 1.9-3.9), somatising tendency (OR 0.6, 95% CI 0.4-0.9), diabetes (OR 1.6, 95% CI 0.9-3.1) and work with vibratory tools (OR 1.4, 95% CI 0.9-2.2).

CONCLUSIONS

When viewed in the context of earlier research, our findings suggest that obesity, diabetes, use of hand-held vibratory tools, and repeated forceful movements of the wrist and hand are causes of impaired median nerve function. In addition, sensory symptoms in the hand, whether from identifiable pathology or non-specific in origin, may be rendered more prominent and distressing by hand activity, low mood, tendency to somatise, and psychosocial stressors at work. These differences in associations with risk factors support the validity of our definition of impaired median nerve conduction.

Smoking and carpal tunnel syndrome: a meta-analysis

INTRODUCTION

We assessed the association between smoking and carpal tunnel syndrome (CTS) and estimated the magnitude of the association with meta-analysis.

METHODS

The PubMed, Embase, Scopus, and SciVerse databases were searched through December 2012. Thirteen studies were included in the meta-analysis.

RESULTS

Cross-sectional studies reported an association between current smoking and CTS (pooled odds ratio (OR) = 1.99, 95% confidence interval (CI) 1.38-2.60, I-squared = 0%). Meta-analyses of case-control studies did not, however, show an association between smoking and CTS (pooled OR = 1.04, 95% CI 0.95-1.12, I-squared = 0.0%) or surgery due to CTS (pooled OR = 0.99, 95% CI 0.82-1.15, I-squared = 0%). Moreover, smoking was not associated with CTS in the meta-analysis of cohort studies (pooled OR = 0.97, 95% CI 0.45-1.50, I-squared = 0%).

CONCLUSIONS

We found an association between smoking and CTS in cross-sectional studies. This association should be explored further in appropriately designed case-control and cohort studies. Muscle Nerve 49:345-350, 2014.

Safety and efficacy of an add-on therapy with curcumin phytosome and piperine and/or lipoic acid in subjects with a diagnosis of peripheral neuropathy treated with dexibuprofen

We conducted an 8-week, open, randomized controlled clinical trial on 141 subjects affected by neuropathic pain to investigate the role of an adjunctive therapy added to the administration of dexibuprofen (400 mg twice a day) and based on a multi-ingredient formula (Lipicur), consisting of lipoic acid plus curcumin phytosome and piperine, in patients with a diagnosis of lumbar sciatica, lumbar disk herniation, and/or lumbar canal stenosis (96 subjects), or with carpal tunnel syndrome (45 subjects). A total of 135 participants completed the study. Treatment with the multi-ingredient formula (Lipicur) reduced neuropathic pain by more than 66% in both conditions (subjects with lumbar sciatica and with carpal tunnel syndrome), and these reductions were statistically significant. Moreover, the treatment reduced dexibuprofen use by about 40%. An add-on therapy with only lipoic acid has not shown any significant results. On the basis of its safety and efficacy, Lipicur could be considered an effective complementary therapy to be added to conventional treatments to achieve better efficacy in reducing neuropathic pain.

Therapeutic ultrasound for carpal tunnel syndrome

BACKGROUND

Therapeutic ultrasound may be offered to people experiencing mild to moderate symptoms of carpal tunnel syndrome (CTS). The effectiveness and duration of benefit of this non-surgical intervention remain unclear.

OBJECTIVES

To review the effects of therapeutic ultrasound compared with no treatment, placebo or another non-surgical intervention in people with CTS.

SEARCH METHODS

On 27 November 2012, we searched the Cochrane Neuromuscular Disease Group Specialized Register, CENTRAL (2012, Issue 11 in The Cochrane Library), MEDLINE (January 1966 to November 2012), EMBASE (January 1980 to November 2012), CINAHL Plus (January 1937 to November 2012), and AMED (January 1985 to November 2012).

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing any regimen of therapeutic ultrasound with no treatment, a placebo or another non-surgical intervention in people with CTS.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, extracted data and assessed the risk of bias in the included studies. We calculated risk ratio (RR) and mean difference (MD) with 95% confidence intervals (CIs) for primary and secondary outcomes. We pooled results of clinically homogenous trials in a meta-analysis using a random-effects model, where possible, to provide estimates of the effect.

MAIN RESULTS

We included 11 studies including 414 participants in the review. Two trials compared therapeutic ultrasound with placebo, two compared one ultrasound regimen with another, two compared ultrasound with another non-surgical intervention, and six compared ultrasound as part of a multi-component intervention with another non-surgical intervention (for example, exercises and splint). The risk of bias was low in some studies and unclear or high in other studies, with only two reporting that the allocation sequence was concealed and six reporting that participants were blinded. Overall, there is insufficient evidence that one therapeutic ultrasound regimen is more efficacious than another. Only two studies reported the primary outcome of interest, short-term overall improvement (any measure in which patients indicate the intensity of their complaints compared with baseline, for example, global rating of improvement, satisfaction with treatment, within three months post-treatment). One low quality trial with 68 participants found that when compared with placebo, therapeutic ultrasound may increase the chance of experiencing short-term overall improvement at the end of seven weeks treatment (RR 2.36; 95% CI 1.40 to 3.98), although losses to follow-up and failure to adjust for the correlation between wrists in participants with bilateral CTS in this study suggest that this data should be interpreted with caution. Another low quality trial with 60 participants found that at three months post-treatment therapeutic ultrasound plus splint increased the chance of short-term overall improvement (patient satisfaction) when compared with splint alone (RR 3.02; 95% CI 1.36 to 6.72), but decreased the chance of short-term overall improvement when compared with low-level laser therapy plus splint (RR 0.87; 95% CI 0.57 to 1.33), though participants were not blinded to treatment, it was unclear if the random allocation sequence was adequately concealed, and there was a potential unit of analysis error. Differences between groups receiving different frequencies and intensities of ultrasound, and between ultrasound as part of a multi-component intervention versus other non-surgical interventions, were generally small and not statistically significant for symptoms, function, and neurophysiologic parameters. No studies reported any adverse effects of therapeutic ultrasound, but this outcome was only measured in three studies. More adverse effects data are required before any firm conclusions on the safety of therapeutic ultrasound can be made.

AUTHORS' CONCLUSIONS

There is only poor quality evidence from very limited data to suggest that therapeutic ultrasound may be more effective than placebo for either short- or long-term symptom improvement in people with CTS. There is insufficient evidence to support the greater benefit of one type of therapeutic ultrasound regimen over another or to support the use of therapeutic ultrasound as a treatment with greater efficacy compared to other non-surgical interventions for CTS, such as splinting, exercises, and oral drugs. More methodologically rigorous studies are needed to determine the effectiveness and safety of therapeutic ultrasound for CTS.

The effect of aging on muscle activation and postural control pattern for young and older computer users

A lot of older adults try to learn to use computers and might use different ways to perform a computer task compared to younger people. Fifteen healthy young and 15 healthy older adults participated in this study and all performed a series of mouse tasks. A three dimensional motion capture system and electromyographic analysis were used to obtain kinematic and kinetic data during performing the computer tasks. Three-way analysis of variance with repeated measures on task and time factors was used to analyze all dependent measurements. Older adults had higher RMS of forearm muscles compared to the young adults. The RMS of the finger extensor was highest when performing a dragging task. Compared with young adults, the older adults had greater cranial-cervical angle and neck flexion, but smaller head flexion, shoulder angle, elbow angle and ulnar deviation. Consequently, the older adults might have a greater risk of developing musculoskeletal disorder.

The outcome of carpal tunnel decompression in patients with diabetes mellitus

Diabetes mellitus is recognised as a risk factor for carpal tunnel syndrome. The response to treatment is unclear, and may be poorer than in non-diabetic patients. Previous randomised studies of interventions for carpal tunnel syndrome have specifically excluded diabetic patients. The aim of this study was to investigate the epidemiology of carpal tunnel syndrome in diabetic patients, and compare the outcome of carpal tunnel decompression with non-diabetic patients. The primary endpoint was improvement in the QuickDASH score. The prevalence of diabetes mellitus was 11.3% (176 of 1564). Diabetic patients were more likely to have severe neurophysiological findings at presentation. Patients with diabetes had poorer QuickDASH scores at one year post-operatively (p = 0.028), although the mean difference was lower than the minimal clinically important difference for this score. After controlling for underlying differences in age and gender, there was no difference between groups in the magnitude of improvement after decompression (p = 0.481). Patients with diabetes mellitus can therefore be expected to enjoy a similar improvement in function.

Exercise and mobilisation interventions for carpal tunnel syndrome

BACKGROUND

Non-surgical treatment, including exercises and mobilisation, has been offered to people experiencing mild to moderate symptoms arising from carpal tunnel syndrome (CTS). However, the effectiveness and duration of benefit from exercises and mobilisation for this condition remain unknown.

OBJECTIVES

To review the efficacy and safety of exercise and mobilisation interventions compared with no treatment, a placebo or another non-surgical intervention in people with CTS.

SEARCH METHODS

We searched the Cochrane Neuromuscular Disease Group Specialised Register (10 January 2012), CENTRAL (2011, Issue 4), MEDLINE (January 1966 to December 2011), EMBASE (January 1980 to January 2012), CINAHL Plus (January 1937 to January 2012), and AMED (January 1985 to January 2012).

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials comparing exercise or mobilisation interventions with no treatment, placebo or another non-surgical intervention in people with CTS.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed searches and selected trials for inclusion, extracted data and assessed risk of bias of the included studies. We calculated risk ratios (RR) and mean differences (MD) with 95% confidence intervals (CIs) for primary and secondary outcomes of the review. We collected data on adverse events from included studies.

MAIN RESULTS

Sixteen studies randomising 741 participants with CTS were included in the review. Two compared a mobilisation regimen to a no treatment control, three compared one mobilisation intervention (for example carpal bone mobilisation) to another (for example soft tissue mobilisation), nine compared nerve mobilisation delivered as part of a multi-component intervention to another non-surgical intervention (for example splint or therapeutic ultrasound), and three compared a mobilisation intervention other than nerve mobilisation (for example yoga or chiropractic treatment) to another non-surgical intervention. The risk of bias of the included studies was low in some studies and unclear or high in other studies, with only three explicitly reporting that the allocation sequence was concealed, and four reporting blinding of participants. The studies were heterogeneous in terms of the interventions delivered, outcomes measured and timing of outcome assessment, therefore, we were unable to pool results across studies. Only four studies reported the primary outcome of interest, short-term overall improvement (any measure in which patients indicate the intensity of their complaints compared to baseline, for example, global rating of improvement, satisfaction with treatment, within three months post-treatment). However, of these, only three fully reported outcome data sufficient for inclusion in the review. One very low quality trial with 14 participants found that all participants receiving either neurodynamic mobilisation or carpal bone mobilisation and none in the no treatment group reported overall improvement (RR 15.00, 95% CI 1.02 to 220.92), though the precision of this effect estimate is very low. One low quality trial with 22 participants found that the chance of being 'satisfied' or 'very satisfied' with treatment was 24% higher for participants receiving instrument-assisted soft tissue mobilisation compared to standard soft tissue mobilisation (RR 1.24, 95% CI 0.89 to 1.75), though participants were not blinded and it was unclear if the allocation sequence was concealed. Another very low-quality trial with 26 participants found that more CTS-affected wrists receiving nerve gliding exercises plus splint plus activity modification had no pathologic finding on median and ulnar nerve distal sensory latency assessment at the end of treatment than wrists receiving splint plus activity modification alone (RR 1.26, 95% CI 0.69 to 2.30). However, a unit of analysis error occurred in this trial, as the correlation between wrists in participants with bilateral CTS was not accounted for. Only two studies measured adverse effects, so more data are required before any firm conclusions on the safety of exercise and mobilisation interventions can be made. In general, the results of secondary outcomes of the review (short- and long-term improvement in CTS symptoms, functional ability, health-related quality of life, neurophysiologic parameters, and the need for surgery) for most comparisons had 95% CIs which incorporated effects in either direction.

AUTHORS' CONCLUSIONS

There is limited and very low quality evidence of benefit for all of a diverse collection of exercise and mobilisation interventions for CTS. People with CTS who indicate a preference for exercise or mobilisation interventions should be informed of the limited evidence of effectiveness and safety of this intervention by their treatment provider. Until more high quality randomised controlled trials assessing the effectiveness and safety of various exercise and mobilisation interventions compared to other non-surgical interventions are undertaken, the decision to provide this type of non-surgical intervention to people with CTS should be based on the clinician's expertise in being able to deliver these treatments and patient's preferences.

Therapeutic ultrasound for carpal tunnel syndrome

BACKGROUND

Therapeutic ultrasound may be offered to people experiencing mild to moderate symptoms of carpal tunnel syndrome (CTS). The effectiveness and duration of benefit of this non-surgical intervention remain unclear.

OBJECTIVES

To review the effects of therapeutic ultrasound compared with no treatment, placebo or another non-surgical intervention in people with CTS.

SEARCH METHODS

We searched the Cochrane Neuromuscular Disease Group Specialized Register (22 February 2011), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library, 2011, Issue 1), MEDLINE (January 1966 to February 2011), EMBASE (January 1980 to February 2011), CINAHL Plus (January 1937 to February 2011), and AMED (January 1985 to February 2011).

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing any regimen of therapeutic ultrasound with no treatment, a placebo or another non-surgical intervention in people with CTS.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected trials for inclusion, extracted data and assessed the risk of bias in the included studies. We calculated risk ratio (RR) and mean difference (MD) with 95% confidence intervals (CIs) for primary and secondary outcomes. We pooled results of clinically homogenous trials in a meta-analysis using a random-effects model, where possible, to provide estimates of the effect.

MAIN RESULTS

We included 11 studies randomising 443 patients in the review. Two trials compared therapeutic ultrasound with placebo, two compared one ultrasound regimen with another, two compared ultrasound with another non-surgical intervention, and six compared ultrasound as part of a multi-component intervention with another non-surgical intervention (for example, exercises and splint). The risk of bias was low in some studies and unclear or high in other studies, with only three reporting that the allocation sequence was concealed and six reporting that participants were blinded. Overall, there is insufficient evidence that one therapeutic ultrasound regimen is more efficacious than another. Only two studies reported the primary outcome of interest, short-term overall improvement (any measure in which patients indicate the intensity of their complaints compared with baseline, for example, global rating of improvement, satisfaction with treatment, within three months post-treatment). One low quality trial with 68 participants found that when compared with placebo, therapeutic ultrasound may increase the chance of experiencing short-term overall improvement at the end of seven weeks treatment (RR 2.36; 95% CI 1.40 to 3.98), although losses to follow-up in this study suggest that these data should be interpreted with caution. Another low quality trial with 60 participants found that at three months, post-treatment therapeutic ultrasound plus splint increased the chance of short-term overall improvement (patient satisfaction) when compared with splint alone (RR 3.02; 95% CI 1.36 to 6.72), but decreased the chance of short-term overall improvement when compared with low-level laser therapy plus splint (RR 0.87; 95% CI 0.57 to 1.33), though participants were not blinded to treatment and it was unclear if the random allocation sequence was adequately concealed. Differences between groups receiving different frequencies and intensities of ultrasound, and between ultrasound as part of a multi-component intervention versus other non-surgical interventions, were generally small and not statistically significant for symptoms, function, and neurophysiologic parameters. Only four studies measured adverse effects, none of which identified adverse effects due to therapeutic ultrasound. However, more data on this outcome are required before any firm conclusions on the safety of this intervention can be made.

AUTHORS' CONCLUSIONS

There is only poor quality evidence from very limited data to suggest that therapeutic ultrasound may be more effective than placebo for either short- or long-term symptom improvement in people with CTS. There is insufficient evidence to support the greater benefit of one type of therapeutic ultrasound regimen over another or to support the use of therapeutic ultrasound as a treatment with greater efficacy compared to other non-surgical interventions for CTS, such as splinting, exercises, and oral drugs. More methodologically rigorous studies are needed to determine the effectiveness and safety of this intervention for CTS.

Musculoskeletal stress marker (MSM) differences in the modern American upper limb and pectoral girdle in relation to activity level and body mass index (BMI)

Obesity is a widespread condition affecting modern Americans. The prevalence of obesity has led to questions of how it can affect the skeleton, and if so can it be identified in unknown skeletal material. This study attempts to decipher the effects of activity level and body mass in modern Americans by employing musculoskeletal stress markers (MSM) to estimate osseous responses to workload and body weight. A total sample of 108 skeletons of known activity level and body mass index (BMI) was observed for MSM in the upper extremity (excluding hands). The entheses selected included arm muscles used during the sit-to-stand transition, which is common in most persons, regardless of activity level and BMI. Using the three categories: normal, active, and obese, logistic regression was calculated on MSM to ascertain which markers were the best indicators of these three categories. Numerous muscles of the upper limb were significant predictors of activity level and body mass, although they did not perform much better than chance. MSM may be used as predictors of activity level and/or BMI in forensic contexts; however, they should be used in conjunction with other indications of workload and/or BMI.

Increased prevalence of carpal tunnel syndrome in albright hereditary osteodystrophy

CONTEXT

Albright hereditary osteodystrophy (AHO) is a rare genetic disorder characterized by phenotypic abnormalities including brachydactyly/brachymetacarpia, short stature, and sc ossifications. Carpal tunnel syndrome (CTS) is a chief complaint in many patients with AHO.

OBJECTIVE

The objective of the study was to investigate the prevalence of CTS in patients with AHO.

DESIGN

This was a cross-sectional study.

SETTING

The study was conducted at the Clinical Research Center (Institute of Clinical and Translational Medicine), Johns Hopkins University School of Medicine and Albright Clinic, Kennedy Krieger Institute.

PARTICIPANTS

Thirty-three subjects with a diagnosis of AHO participated in the study.

MAIN OUTCOME MEASURES

We assessed for the presence and location of hand tingling, numbness, pain, weakness, flick sign, difficulty with fine motor skills, severe hand or nail biting, and nocturnal symptoms in the setting of normocalcemia and a euthyroid state. Patients were considered to have CTS if they were positive for three of these symptoms. All subjects were analyzed for mutations in the GNAS gene.

RESULTS

Twenty-two subjects (67%) had a clinical diagnosis of CTS (95% confidence interval 0.48, 0.82). Twenty-eight of 33 subjects were confirmed to have mutations in GNAS, of whom 68% had CTS (95% confidence interval 0.48, 0.84). There were 14 children in this study; 36% had a clinical diagnosis of CTS. Body mass index, brachydactyly/brachymetacarpia, prior GH treatment, and specific GNAS mutations were not associated with CTS.

CONCLUSIONS

We report a high prevalence of CTS in both adults and children with AHO. The diagnosis of CTS should be considered when evaluating a patient with AHO because the intervention for CTS could improve overall function and quality of life in these patients.

Preferred sleep position on the side is associated with carpal tunnel syndrome

BACKGROUND

Although carpal tunnel syndrome is the most common compressive neuropathy, there is no comprehensive theory of its etiology. Because of the prevalence of night symptoms, we are interested in the role of sleep position in the causation of carpal tunnel syndrome.

METHODS

We performed a case-control study comparing the prevalence of preferred sleep position in 68 cases and 138 controls. Analysis was stratified by age and gender and controlled for body mass index.

RESULTS

We found a strong and significant association between a preference for sleeping on the side and the presence of carpal tunnel syndrome in men and in women less than 60 years of age. Body mass index was associated with carpal tunnel syndrome in women but not men.

CONCLUSIONS

Our findings of a strong association between the presence of carpal tunnel syndrome and preferred sleeping on the side suggest a comprehensive unifying theory of causation.

Associations of cardiovascular risk factors, carotid intima-media thickness and manifest atherosclerotic vascular disease with carpal tunnel syndrome

BACKGROUND

The role of atherosclerosis in carpal tunnel syndrome (CTS) has not previously been addressed in population studies. The aim of this study was to investigate the associations of cardiovascular risk factors, carotid artery intima-media thickness (IMT), and clinical atherosclerotic diseases with CTS.

METHODS

In this cross sectional study, the target population consisted of subjects aged 30 or over who had participated in the national Finnish Health Survey in 2000-2001. Of the 7977 eligible subjects, 6254 (78.4%) were included in our study. Carotid IMT was measured in a sub-sample of subjects aged 45 to 74 (N=1353).

RESULTS

Obesity (adjusted odds ratio (OR) 2.4, 95% confidence interval (CI) 1.1-5.4), high LDL cholesterol (OR 3.8, 95% CI 1.6-9.1 for >190 vs. <129 mg/dL), high triglycerides (OR 2.7, 95% CI 1.2-6.1 for >200 vs. <150 mg/dL), hypertension (OR 3.4, 95% CI 1.6-7.4) and cardiac arrhythmia (OR 10.2, 95% CI 2.7-38.4) were associated with CTS in subjects aged 30-44. In the age group of 60 years or over, coronary artery disease (OR 1.9, 95% CI 1.1-3.5), valvular heart disease (OR 2.3, 95% CI 1.0-5.0) and carotid IMT (1.4, 95% CI 0.9-2.1 for each 0.23 mm increase) were associated with CTS. Carotid IMT was associated with CTS only in subjects with hypertension or clinical atherosclerotic vascular disease, or in those who were exposed to physical workload factors.

CONCLUSIONS

Our findings suggest an association between CTS and cardiovascular risk factors in young people, and carotid IMT and clinical atherosclerotic vascular disease in older people. CTS may either be a manifestation of atherosclerosis, or both conditions may share similar risk factors.

Evaluation of sleep position as a potential cause of carpal tunnel syndrome: preferred sleep position on the side is associated with age and gender

PURPOSE

To test the hypothesis that an important step in a causative mechanism for carpal tunnel syndrome (CTS) is sleeping in a lateral position (sleeping on the side), we designed a cross-sectional survey to measure the association between sleep position, age, gender, and body mass index (BMI).

METHODS AND FINDINGS

We surveyed 247 patients in a primary care setting. Fifty percent of men and 73% of women prefer to sleep on their side (p < .001; unadjusted odds ratio, 2.7). In addition, the proportion of women who prefer to sleep on their side increased with increasing age (p < .001). There was no association between BMI and sleeping in a lateral position.

CONCLUSIONS

This study supports the hypothesis that sleeping on the side is an important step in a causal pathway for CTS.

The role of sexual intercourse in the etiology of carpal tunnel syndrome

The etiology of non-occupational carpal tunnel syndrome is not well understood. It is proposed that carpal tunnel syndrome can develop during sexual intercourse when the hands become repeatedly extended while under pressure from the weight of the upper body. Of the eight risk factors associated with non-occupational carpal tunnel syndrome, age, marital status, pregnancy and use of hormonal agents can be explained by changes in the frequency of sexual intercourse. On the other hand, obesity, macromastia and large chest circumference can be explained by the increased pressure imposed on the wrists by the heavier upper body associated with such conditions. The bilaterality of carpal tunnel syndrome can be explained by the fact that both hands are needed to support the upper body during sexual intercourse. A parallel decrease in the frequency of sexual intercourse and the incidence of carpal tunnel syndrome between the sixth and the seventh decades of life suggests a possible cause and effect relationship between sexual intercourse and carpal tunnel syndrome.

Risk factors for operated carpal tunnel syndrome: a multicenter population-based case-control study

BACKGROUND

Carpal tunnel syndrome (CTS) is a socially and economically relevant disease caused by compression or entrapment of the median nerve within the carpal tunnel. This population-based case-control study aims to investigate occupational/non-occupational risk factors for surgically treated CTS.

METHODS

Cases (n = 220) aged 18-65 years were randomly drawn from 13 administrative databases of citizens who were surgically treated with carpal tunnel release during 2001. Controls (n = 356) were randomly sampled from National Health Service registry records and were frequency matched by age-gender-specific CTS hospitalization rates.

RESULTS

At multivariate analysis, risk factors were blue-collar/housewife status, BMI > or = 30 kg/m2, sibling history of CTS and coexistence of trigger finger. Being relatively tall (cut-offs based on tertiles: women > or =165 cm; men > or =175 cm) was associated with lower risk. Blue-collar work was a moderate/strong risk factor in both sexes. Raised risks were apparent for combinations of biomechanical risk factors that included frequent repetitivity and sustained force.

CONCLUSION

This study strongly underlines the relevance of biomechanical exposures in both non-industrial and industrial work as risk factors for surgically treated CTS.

The relationship of presence or absence of palmaris longus and fifth flexor digitorum superficialis with carpal tunnel syndrome

BACKGROUND AND PURPOSE

This study was designed to find a possible correlation between the presence of the palmaris longus (PL) tendon and function of the fifth flexor digitorum superficialis (FDS) and carpal tunnel syndrome (CTS).

METHODS

The CTS and normal groups consisted of 60 and 180 hands, respectively. The diagnosis of CTS was confirmed by detailed history taking, physical examination and electrodiagnostic testing. The presence of the PL tendon and function of the fifth FDS were determined by physical examination.

RESULTS

In the CTS group, 16/60 hands (26.7%) did not have a PL tendon and 18/60 hands (30%) were lacking fifth FDS function. In the normal group, 27/180 hands (15%) lacked the PL and 25/180 (13.9%) lacked a functional fifth FDS (P = 0.041 and 0.005 for PL and FDS, respectively). Pain distribution and severity of the disease were not related to absence of either of these tendons (P > 0.05).

CONCLUSION

Our findings showed that the absence of the PL tendon and fifth FDS function, independently and in combination, is more frequent in patients with CTS. Also we found that the severity of CTS or pain distribution in these patients was not related to the presence or absence of these tendons.

The quality and strength of evidence for etiology: example of carpal tunnel syndrome

PURPOSE

The purpose of this investigation was to evaluate the quality and strength of scientific evidence supporting an etiologic relationship between a disease and a proposed risk factor using a scoring system based on the Bradford Hill criteria for causal association.

METHODS

A quantitative score based on the Bradford Hill criteria (qBHs) was used to evaluate 117 articles presenting original data regarding the etiology of carpal tunnel syndrome: 33 (28%) that evaluated biological (structural or genetic) risk factors, 51 (44%) that evaluated occupational (environment or activity-related) risk factors, and 33 (28%) that evaluated both types of risk factors.

RESULTS

The quantitative Bradford Hill scores of 2 independent observers showed very good agreement, supporting the reliability of the instrument. The average qBHs was 12.2 points (moderate association) among biological risk factors compared with 5.2 points (poor association) for occupational risk factors. The highest average qBHs was observed for genetic factors (14.2), race (11.7), and anthropometric measures of the wrist (11.3 points) with all studies finding a moderate causal association. The highest average qBHs among occupational risk factors was observed for activities requiring repetitive hand use (6.5 points among the 30 of 45 articles that reported a causal association), substantial exposure to vibration (6.3 points; 14 of 20 articles), and type of occupation (5.6 points; 38 of 53 articles), with the findings being much less consistent.

CONCLUSIONS

According to a quantitative analysis of published scientific evidence, the etiology of carpal tunnel syndrome is largely structural, genetic, and biological, with environmental and occupational factors such as repetitive hand use playing a minor and more debatable role. Speculative causal theories should be analyzed through a rigorous approach prior to wide adoption.

Obesity and presenteeism: the impact of body mass index on workplace productivity

OBJECTIVE

To examine whether obesity is associated with increased presenteeism (health-related limitations at work).

METHODS

Randomly selected manufacturing employees (n = 341) were assessed via height and weight measures, demographic survey, wage data, and the Work Limitations Questionnaire. The Work Limitations Questionnaire measures productivity on four dimensions. Analyses of variance and analyses of covariance were computed to identify productivity differences based on body mass index (BMI).

RESULTS

Moderately or extremely obese workers (BMI > or =35) experienced the greatest health-related work limitations, specifically regarding time needed to complete tasks and ability to perform physical job demands. These workers experienced a 4.2% health-related loss in productivity, 1.18% more than all other employees, which equates to an additional $506 annually in lost productivity per worker.

CONCLUSIONS

The relationship between BMI and presenteeism is characterized by a threshold effect, where extremely or moderately obese workers are significantly less productive than mildly obese workers.

High-fat diet induced neuropathy of pre-diabetes and obesity: effects of "healthy" diet and aldose reductase inhibition

OBJECTIVE

Subjects with dietary obesity and pre-diabetes have an increased risk for developing both nerve conduction slowing and small sensory fiber neuropathy. Animal models of this type of neuropathy have not been described. This study evaluated neuropathic changes and their amenability to dietary and pharmacological interventions in mice fed a high-fat diet (HFD), a model of pre-diabetes and alimentary obesity.

RESEARCH DESIGN AND METHODS

Female C57BL6/J mice were fed normal diets or HFDs for 16 weeks.

RESULTS

HFD-fed mice developed obesity, increased plasma FFA and insulin concentrations, and impaired glucose tolerance. They also had motor and sensory nerve conduction deficits, tactile allodynia, and thermal hypoalgesia in the absence of intraepidermal nerve fiber loss or axonal atrophy. Despite the absence of overt hyperglycemia, the mice displayed augmented sorbitol pathway activity in the peripheral nerve, as well as 4-hydroxynonenal adduct nitrotyrosine and poly(ADP-ribose) accumulation and 12/15-lipoxygenase overexpression in peripheral nerve and dorsal root ganglion neurons. A 6-week feeding with normal chow after 16 weeks on HFD alleviated tactile allodynia and essentially corrected thermal hypoalgesia and sensory nerve conduction deficit without affecting motor nerve conduction slowing. Normal chow containing the aldose reductase inhibitor fidarestat (16 mg x kg(-1) x day (-1)) corrected all functional changes of HFD-induced neuropathy.

CONCLUSIONS

Similar to human subjects with pre-diabetes and obesity, HFD-fed mice develop peripheral nerve functional, but not structural, abnormalities and, therefore, are a suitable model for evaluating dietary and pharmacological approaches to halt progression and reverse diabetic neuropathy at the earliest stage of the disease.

The impact of obesity on the musculoskeletal system

Obesity is associated with a range of disabling musculoskeletal conditions in adults. As the prevalence of obesity increases, the societal burden of these chronic musculoskeletal conditions, in terms of disability, health-related quality of life, and health-care costs, also increases. Research exploring the nature and strength of the associations between obesity and musculoskeletal conditions is accumulating, providing a better understanding of underlying mechanisms. Weight reduction is important in ameliorating some of the manifestations of musculoskeletal disease and improving function.

Epidemiologic associations of carpal tunnel syndrome and sleep position: Is there a case for causation?

INTRODUCTION

Carpal tunnel syndrome (CTS) is thought to be due to compression of the median nerve in the carpal tunnel. It is known that carpal tunnel pressures are elevated in wrist postures of flexion and extension and in those patients with CTS. Classic symptoms of CTS include night waking with pain, tingling, and numbness. These classic symptoms stimulated our interest in the relationship of sleep to the development of CTS.

METHOD

We reviewed the literature surrounding the epidemiology of CTS and the literature regarding sleep disturbances. Through careful distillation of these studies and a process of reasoning, we have developed a hypothesis for a causal mechanism of CTS.

RESULTS

Epidemiologically, it has been shown that CTS is associated with age, gender, increased body mass index (BMI), diabetes, pregnancy, and is more common in some populations. The same associations noted above for CTS are strongly associated with sleep disturbances. Sleep disturbances due to age, gender, BMI, pregnancy, and population variations are all associated with sleeping in the lateral position supporting the hypothesis that a common causative mechanism of CTS is sleeping in a lateral position.

DISCUSSION

We believe that the epidemiologic associations with CTS act through a common causative mechanism, increased sleeping in the lateral position which puts the wrist at increased risk of flexion or extension, compressing the median nerve in the carpal tunnel. This hypothesis is simple and explains the connection between a previously unconnected group of epidemiologic associations. This realization has real clinical significance in that it focuses our attention on the early disorder when it is completely reversible. It clarifies previously confused clinical circumstances, creates research questions that can be tested, and it invites us to change our clinical perspective in this most common form of nerve compression.

Obesity after spinal cord injury

America is in the midst of an obesity epidemic, and individuals who have spinal cord injury (SCI) are perhaps at greater risk than any other segment of the population. Recent changes in the way obesity has been defined have lulled SCI practitioners into a false sense of security about the health of their patients regarding the dangers of obesity and its sequelae. This article defines and uses a definition of obesity that is more relevant to persons who have SCI, reviews the physiology of adipose tissue, and discusses aspects of heredity and environment that contribute to obesity in SCI. The pathophysiology of obesity is discussed relative to health risks for persons who have SCI, particularly those contributing to cardiovascular disease. Prevalence of obesity and its comorbidities are discussed and management options reviewed.

Carpal tunnel syndrome in older adults

The clinical and electrophysiologic characteristics of carpal tunnel syndrome (CTS) in elderly adults are not well established. We examined age differences in clinical, functional, and electrophysiologic features in elderly adults referred to a neuromuscular service for evaluation of symptoms suggestive of CTS. Of 415 consecutive subjects referred over an 18-month period, 343 met clinical criteria for CTS. There were 158 young (<or=50 years), 115 middle-aged (51-64 years), and 70 elderly adults (>or=65 years). There were no age differences in the duration of CTS symptoms, hand function, or presence of autonomic symptoms. The elderly adults had a higher prevalence of thenar weakness and thenar atrophy than younger subjects. Electrophysiologic abnormalities were more common and more severe in the older subjects. Our study shows that although there are no age differences in subjective complaints of CTS, older adults had objective clinical and electrophysiologic evidence of a more severe median nerve entrapment. The findings suggest that greater attention needs to be paid to objective evidence of CTS severity rather than subjective complaints when evaluating elderly adults presenting for clinical evaluation of CTS.

Relationship between repetitive work and the prevalence of carpal tunnel syndrome in part-time and full-time female supermarket cashiers: a quasi-experimental study

OBJECTIVES

To investigate the prevalence of Carpal Tunnel Syndrome (CTS) in full-time and part-time supermarket cashiers exposed to a different weekly duration of biomechanical load.

METHODS

All the 269 cashiers and 127 office workers were asked to participate. The protocol included ergonomic risk assessment, collection of personal and clinical data and bilateral electrodiagnostic study of the median nerve. CTS symptoms were defined as past and/or current nocturnal and/or diurnal numbness, tingling, burning or pain involving at least one of the first three fingers. Results were evaluated according to two case definitions based on current symptoms and on the combination of current symptoms and slowing of sensory conduction velocity from wrist to palm, respectively. Difference in proportions of CTS symptoms and cases was evaluated by the Pearson's chi-square (chi(2)) test, univariate and multivariate logistic regression analyses were performed to determine the impact of weekly exposure.

RESULTS

The final female study population included 71 full-time cashiers, 155 part-time cashiers and 98 office workers. Ergonomic risk level was rated 5 for hand activity level and 4 for peak of force according to ACGIH. The intersection of the two values fell on the threshold limit value line, confirming the possible exposure to biomechanical risk factors for CTS. The prevalence of current CTS symptoms was higher among full-time (31.0%) than in part-time cashiers (19.3%) or controls (16.3%) (p = 0.055). A similar pattern was found for CTS past symptoms and cases. Univariate analysis showed that full-time cashiers had a 2.3 fold increased risk for CTS specific current symptoms than control subjects. A similar trend also emerged for CTS cases but was not significant (Odds ratios 1.23). Multivariate logistic regression analysis confirmed the increased risk for CTS current symptoms in full-time cashiers.

CONCLUSIONS

Intensive manual work associated with inadequate recovery time might have generated an impairment of the median nerve at the wrist level proportionally increasing with duration of hand use. Our study can provide useful information both for ergonomic risk assessment and work organization.

Diagnosing carpal tunnel syndrome—clinical criteria and ancillary tests

Damage to the median nerve within the carpal tunnel gives rise to carpal tunnel syndrome (CTS), which is associated with a wide spectrum of symptoms. The predominant classic symptoms are nocturnal pain of the hand, and sensory disturbances within the distribution of the median nerve, both of which are characteristically relieved by hand movements. Ancillary tests, including nerve conduction studies (NCS) and imaging techniques, are mainly indicated when the classic defining features are absent. NCS are less accurate in the early stages of CTS, and in younger patients. Imaging tests (ultrasound and MRI), while still having a lower diagnostic accuracy than NCS, are proving to be useful for explaining persistence of symptoms following surgical relief. Supplementary tests of small nerve fiber function and measurement of intracarpal pressure might, in the future, improve early recognition of CTS, especially in the absence of well-defined symptoms.