Grading bias and young adult mental health

We study exposure to grading bias and provide novel evidence of its impact on mental health. Grading bias, which we interpret as over-grading, is constructed as the residual of final upper secondary school grades having controlled for results in a standardized test, itself not subject to grading leniency. Grading bias is further isolated by considering only within-school variation in over-grading and controlling for prior grades and school production. Using Swedish individual-level register data for individuals graduating from upper secondary school in the years 2001-2004, we show that over-grading has substantial significant protective impacts on the mental health of young adults, but only among female students. That grades themselves, independent of knowledge, substantially impact the production of health highlights an important health production mechanism, and implies that any changes to the design of grading systems must consider these wider health implications.

Are respiratory disorders risk factors for troublesome neck/shoulder pain? A study of a general population cohort in Sweden

PURPOSE

The etiology of neck/shoulder pain is complex. Our purpose was to investigate if respiratory disorders are risk factors for troublesome neck/shoulder pain in people with no or occasional neck/shoulder pain.

METHODS

This prospective cohort study was based on the Stockholm Public Health Cohorts (SPHC) 2006/2010 and the SPHC 2010/2014. We included adults who at baseline reported no or occasional neck/shoulder pain in the last six months, from the two subsamples (SPHC 06/10 n = 15 155: and SPHC 2010/14 n = 25 273). Exposures were self-reported asthma at baseline in SPHC 06/10 and Chronic Obstructive Pulmonary Disease (COPD) at baseline in SPHC 10/14. The outcome was having experienced at least one period of troublesome neck/shoulder pain which restricted work capacity or hindered daily activities to some or to a high degree during the past six months, asked for four years later. Binomial regression analyses were used to calculate risk ratios (RR) with 95% confidence intervals (95% CI).

RESULTS

Adjusted results indicate that those reporting to suffer from asthma at baseline had a higher risk of troublesome neck/shoulder pain at follow-up four years later (RR 1.48, 95% CI 1.10-2.01) as did those reporting to suffer from COPD (RR 2.12 95%CI 1.54-2.93).

CONCLUSION

Our findings indicate that those with no or occasional neck/shoulder pain and reporting to suffer from asthma or COPD increase the risk for troublesome neck/shoulder pain over time. This highlights the importance of taking a multi-morbidity perspective into consideration in health care. Future longitudinal studies are needed to confirm our findings.

The health returns of attending university for the marginally eligible student

A key policy question is whether continued expansion of university education is beneficial for the marginally eligible student. In this paper we exploit an arbitrary university eligibility rule combined with regression discontinuity design to estimate the causal effect of university attendance on healthcare utilization amongst young adults in Sweden. We find that the eligibility rule leads to a clear jump in university attendance of between 10% and 14% points for both males and females. 2SLS estimates find that a 10% point increase in university attendance causes a roughly one percentage point increase in hospital admissions due to mental ill health for males, almost exclusively related to alcohol and narcotics. Our findings for females, however, imply the opposite, suggesting that university attendance decreases hospital admissions related to mental health. The results for males sit in contrast to results from previous studies, and suggest that the effect of university education on health for the male student at the margin of eligibility is different to that of the average student.

Job strain as a risk factor for clinical depression: systematic review and meta-analysis with additional individual participant data

BACKGROUND

Adverse psychosocial working environments characterized by job strain (the combination of high demands and low control at work) are associated with an increased risk of depressive symptoms among employees, but evidence on clinically diagnosed depression is scarce. We examined job strain as a risk factor for clinical depression.

METHOD

We identified published cohort studies from a systematic literature search in PubMed and PsycNET and obtained 14 cohort studies with unpublished individual-level data from the Individual-Participant-Data Meta-analysis in Working Populations (IPD-Work) Consortium. Summary estimates of the association were obtained using random-effects models. Individual-level data analyses were based on a pre-published study protocol.

RESULTS

We included six published studies with a total of 27 461 individuals and 914 incident cases of clinical depression. From unpublished datasets we included 120 221 individuals and 982 first episodes of hospital-treated clinical depression. Job strain was associated with an increased risk of clinical depression in both published [relative risk (RR) = 1.77, 95% confidence interval (CI) 1.47-2.13] and unpublished datasets (RR = 1.27, 95% CI 1.04-1.55). Further individual participant analyses showed a similar association across sociodemographic subgroups and after excluding individuals with baseline somatic disease. The association was unchanged when excluding individuals with baseline depressive symptoms (RR = 1.25, 95% CI 0.94-1.65), but attenuated on adjustment for a continuous depressive symptoms score (RR = 1.03, 95% CI 0.81-1.32).

CONCLUSIONS

Job strain may precipitate clinical depression among employees. Future intervention studies should test whether job strain is a modifiable risk factor for depression.

Clinical practice guidelines for the noninvasive management of low back pain: A systematic review by the Ontario Protocol for Traffic Injury Management (OPTIMa) Collaboration

We conducted a systematic review of guidelines on the management of low back pain (LBP) to assess their methodological quality and guide care. We synthesized guidelines on the management of LBP published from 2005 to 2014 following best evidence synthesis principles. We searched MEDLINE, EMBASE, CINAHL, PsycINFO, Cochrane, DARE, National Health Services Economic Evaluation Database, Health Technology Assessment Database, Index to Chiropractic Literature and grey literature. Independent reviewers critically appraised eligible guidelines using AGREE II criteria. We screened 2504 citations; 13 guidelines were eligible for critical appraisal, and 10 had a low risk of bias. According to high-quality guidelines: (1) all patients with acute or chronic LBP should receive education, reassurance and instruction on self-management options; (2) patients with acute LBP should be encouraged to return to activity and may benefit from paracetamol, nonsteroidal anti-inflammatory drugs (NSAIDs), or spinal manipulation; (3) the management of chronic LBP may include exercise, paracetamol or NSAIDs, manual therapy, acupuncture, and multimodal rehabilitation (combined physical and psychological treatment); and (4) patients with lumbar disc herniation with radiculopathy may benefit from spinal manipulation. Ten guidelines were of high methodological quality, but updating and some methodological improvements are needed. Overall, most guidelines target nonspecific LBP and recommend education, staying active/exercise, manual therapy, and paracetamol or NSAIDs as first-line treatments. The recommendation to use paracetamol for acute LBP is challenged by recent evidence and needs to be revisited.

SIGNIFICANCE

Most high-quality guidelines recommend education, staying active/exercise, manual therapy and paracetamol/NSAIDs as first-line treatments for LBP. Recommendation of paracetamol for acute LBP is challenged by recent evidence and needs updating.

Productivity or discrimination? An economic analysis of excess-weight penalty in the Swedish labor market

This article investigates the excess-weight penalty in income for men and women in the Swedish labor market, using longitudinal data. It compares two identification strategies, OLS and individual fixed effects, and distinguishes between two main sources of excess-weight penalties, lower productivity because of bad health and discrimination. For men, the analysis finds a significant obesity penalty related to discrimination when applying individual fixed effects. We do not find any significant excess-weight penalty for women.

Job strain and the risk of severe asthma exacerbations: a meta-analysis of individual-participant data from 100 000 European men and women

Background

Many patients and healthcare professionals believe that work‐related psychosocial stress, such as job strain, can make asthma worse, but this is not corroborated by empirical evidence. We investigated the associations between job strain and the incidence of severe asthma exacerbations in working‐age European men and women.

Methods

We analysed individual‐level data, collected between 1985 and 2010, from 102 175 working‐age men and women in 11 prospective European studies. Job strain (a combination of high demands and low control at work) was self‐reported at baseline. Incident severe asthma exacerbations were ascertained from national hospitalization and death registries. Associations between job strain and asthma exacerbations were modelled using Cox regression and the study‐specific findings combined using random‐effects meta‐analyses.

Results

During a median follow‐up of 10 years, 1 109 individuals experienced a severe asthma exacerbation (430 with asthma as the primary diagnostic code). In the age‐ and sex‐adjusted analyses, job strain was associated with an increased risk of severe asthma exacerbations defined using the primary diagnostic code (hazard ratio, HR: 1.27, 95% confidence interval, CI: 1.00, 1.61). This association attenuated towards the null after adjustment for potential confounders (HR: 1.22, 95% CI: 0.96, 1.55). No association was observed in the analyses with asthma defined using any diagnostic code (HR: 1.01, 95% CI: 0.86, 1.19).

Conclusions

Our findings suggest that job strain is probably not an important risk factor for severe asthma exacerbations leading to hospitalization or death.

Epigenetic regulation of the Igf2/H19 gene cluster

Igf2 (insulin-like growth factor 2) and H19 genes are imprinted in mammals; they are expressed unevenly from the two parental alleles. Igf2 is a growth factor expressed in most normal tissues, solely from the paternal allele. H19 gene is transcribed (but not translated to a protein) from the maternal allele. Igf2 protein is a growth factor particularly important during pregnancy, where it promotes both foetal and placental growth and also nutrient transfer from mother to offspring via the placenta. This article reviews epigenetic regulation of the Igf2/H19 gene-cluster that leads to parent-specific expression, with current models including parental allele-specific DNA methylation and chromatin modifications, DNA-binding of insulator proteins (CTCFs) and three-dimensional partitioning of DNA in the nucleus. It is emphasized that key genomic features are conserved among mammals and have been functionally tested in mouse. 'The enhancer competition model', 'the boundary model' and 'the chromatin-loop model' are three models based on differential methylation as the epigenetic mark responsible for the imprinted expression pattern. Pathways are discussed that can account for allelic methylation differences; there is a recent study that contradicts the previously accepted fact that biallelic expression is accompanied with loss of differential methylation pattern.

Estimation of mass thickness response of embedded aggregated silica nanospheres from high angle annular dark-field scanning transmission electron micrographs

In this study, we investigate the functional behaviour of the intensity in high-angle annular dark field scanning transmission electron micrograph images. The model material is a silica particle (20 nm) gel at 5 wt%. By assuming that the intensity response is monotonically increasing with increasing mass thickness of silica, an estimate of the functional form is calculated using a maximum likelihood approach. We conclude that a linear functional form of the intensity provides a fair estimate but that a power function is significantly better for estimating the amount of silica in the z-direction. The work adds to the development of quantifying material properties from electron micrographs, especially in the field of tomography methods and three-dimensional quantitative structural characterization from a scanning transmission electron micrograph. It also provides means for direct three-dimensional quantitative structural characterization from a scanning transmission electron micrograph.

Socioeconomic inequalities in drug utilization for Sweden: evidence from linked survey and register data

This study analyzes the socioeconomic gradient in drug utilization. We use The Swedish Prescribed Drug Register, merged with the Survey of Living Conditions (the ULF), and the study sample consists of 8138 individuals. We find a positive education gradient (but no income gradient) in drug utilization, after controlling for health indicators. Whereas high-educated men use a larger number of drugs, high-educated women use both a larger number of drugs and more expensive drugs. For males, but not as clearly for females, we find that the education gradient is weaker for more health-related drugs but stronger for more expensive drugs. We conclude that the main reason for the education gradient in drug utilization is doctors' behaviour rather than compliance with medication and affordability of drugs.

The recurrent Guillain-Barré syndrome: a long-term population-based study

OBJECTIVES

To describe a population-based material of patients with recurrent Guillain-Barré syndrome (RGBS), examine the long time course, and search for factors predisposing to recurrence.

MATERIALS AND METHODS

We performed a follow-up study of the neurology and neurophysiology and a systematic study of the acute microbial serology of patients with RGBS. These parameters were compared with the results of a previous study of monophasic GBS.

RESULTS

The patients with RGBS (n = 15) were retrieved from admissions of 229 patients with GBS during a 17-year period. They had 2-7 (median 3) episodes occurring at irregular intervals over decades. Of the 11 patients who accepted a follow-up examination, six were in full remission, and five had moderate sequelae. Nine had a demyelinating subtype, one had an axonal motor variant, and one patient with incomplete Miller Fisher syndrome had associated arachnoiditis. Two patients showed ultimate transition to a course similar to chronic inflammatory demyelinating polyneuropathy. Episodes were generally shorter in RGBS than in GBS, and an initial episode duration <45 days was predictive of recurrence and related to a younger onset age (univariate P = 0.005-0.009). Triggering infections occurred in all patients, in 32 of 41 episodes (78%) with few examples of etiological promiscuity. Serological findings did not differ from those in GBS.

CONCLUSIONS

Episodes in RGBS were shorter than in monophasic GBS. We were unable to identify further immunological predisposing factors for recurrence beyond the previously demonstrated relationship to a weaker respiratory burst. We observed no obvious tendency for the recurrence frequency to wane.

Job strain in relation to body mass index: pooled analysis of 160 000 adults from 13 cohort studies

BACKGROUND

Evidence of an association between job strain and obesity is inconsistent, mostly limited to small-scale studies, and does not distinguish between categories of underweight or obesity subclasses.

OBJECTIVES

To examine the association between job strain and body mass index (BMI) in a large adult population.

METHODS

We performed a pooled cross-sectional analysis based on individual-level data from 13 European studies resulting in a total of 161 746 participants (49% men, mean age, 43.7 years). Longitudinal analysis with a median follow-up of 4 years was possible for four cohort studies (n = 42 222).

RESULTS

A total of 86 429 participants were of normal weight (BMI 18.5-24.9 kg m(-2) ), 2149 were underweight (BMI < 18.5 kg m(-2) ), 56 572 overweight (BMI 25.0-29.9 kg m(-2) ) and 13 523 class I (BMI 30-34.9 kg m(-2) ) and 3073 classes II/III (BMI ≥ 35 kg m(-2) ) obese. In addition, 27 010 (17%) participants reported job strain. In cross-sectional analyses, we found increased odds of job strain amongst underweight [odds ratio 1.12, 95% confidence interval (CI) 1.00-1.25], obese class I (odds ratio 1.07, 95% CI 1.02-1.12) and obese classes II/III participants (odds ratio 1.14, 95% CI 1.01-1.28) as compared with participants of normal weight. In longitudinal analysis, both weight gain and weight loss were related to the onset of job strain during follow-up.

CONCLUSIONS

In an analysis of European data, we found both weight gain and weight loss to be associated with the onset of job strain, consistent with a 'U'-shaped cross-sectional association between job strain and BMI. These associations were relatively modest; therefore, it is unlikely that intervention to reduce job strain would be effective in combating obesity at a population level.

Low back pain in Mozambican adolescents

Recent literature shows that the prevalence of low back pain (LBP) in adolescents living in Western countries approaches that of adults 18-55 years of age. Moreover, epidemiological studies have also shown that the frequency of different rheumatic disorders in developing countries is similar to that found in Western industrialized regions. The purpose of this study was to ascertain the prevalence of LBP and to explore some risk factors among adolescents living in different zones of Mozambique. A previously validated questionnaire was distributed to schoolchildren of grades 6 and 7 living in three different residential/social regions of the country. Two hundred four (204) children participated in the survey. Median age was 13 years (age range 11-16 years) and 46% were boys. Several episodes of LBP interfering with usual activities during the previous year were reported by 13.5% of the sample. Living in the wealthier urban center (as compared with the peripheral regions) and walking >30 min per day to and from school were associated with an increased risk of LBP (OR 3.1, 95% CI 0.99-9.48, and OR 4.8, 95% CI 1.61-14.28, respectively).

Arousal increases baroreflex inhibition of muscle sympathetic activity

AIM

Surprising sensory stimuli causing arousal are known to evoke short-lasting activation of human sympathetic activity in skin but not in muscle nerves. In fact, anecdotal observations suggest that muscle sympathetic activity may be inhibited. To test this hypothesis, the effects of surprising somatosensory (electrical skin pulses) or visual (flash) stimuli on multiunit muscle sympathetic activity were studied in 36 healthy subjects, aged 19-71 years.

METHODS

The stimuli were given either 200 or 400 ms after the R-wave of the electrocardiogram. Dummy stimuli, consisting of trigger pulses without sensory stimuli, served as controls.

RESULTS

On a group basis, a single sensory stimulus of either type attenuated the amplitude of one or two sympathetic bursts, while no such effects occurred after dummy stimuli. Individually, the inhibition was evoked by at least one stimulus modality or delay in 16 subjects, whereas in three subjects no significant inhibition occurred. Electrodermal signs of skin sympathetic activation were present in all subjects. Compared with one, five repeated electrical skin pulses induced only minor additional inhibition of muscle sympathetic activity, indicating marked habituation of the neural response. In nine subjects, the experiments were repeated once and in three subjects twice (with intervals of 2-3 months); in 11 of the 12 subjects, the sympathetic effects were reproducible. In the group of subjects without significant sympathetic inhibition the stimuli induced a small, transient increase of mean blood pressure, which was not present in the group with sympathetic inhibition.

CONCLUSION

The finding that different sensory stimuli induce similar effects that habituate markedly on repetition suggests that the inhibition of muscle sympathetic activity is because of arousal. The interindividual differences in sympathetic and blood pressure effects may be part of interindividual differences in behavioural responses to stress.

A 2-year prospective longitudinal study on low back pain in primary school children

There is increasing evidence that non-specific low back pain (LBP) is common among children and adolescents, but there are few longitudinal studies on this subject. This is a longitudinal prospective study aimed at finding factors associated with the prediction of low back pain in schoolchildren aged 9-12 years, which is a younger age group than has previously been studied. This study was performed on school children in the city of Antwerp, Belgium. A total of 287 children filled out a questionnaire and were examined at the beginning of the study (T1) and 2 years later (T2). The questionnaire asked about back pain, general health, health perceptions, quality of life perceptions, sports, leisure, daily life, school life (weight of satchel.) and some issues related to parents (smoking, LBP). The questionnaire reliability was tested. Logistic regression was used to analyse the data. No predictors for LBP in children could be identified. Using logistic regression techniques, we analysed the children who reported no lifetime episode of LBP at both T1 and T2, the children who did report a lifetime episode at both T1 and T2 and also those who reported a history of LBP at T2 only (New LBP). At T2 there were 51 children (17.8%) reporting suffering at least one lifetime episode of LBP who had not reported such an episode at T1. Only one parameter showed a statistical difference: New LBP was observed significantly more frequently in children who do not walk to school ( P<0.0001). An interesting point of this study is that a number of children who had reported a history of LBP at T1 did not do so at T2. It may be that LBP in children is so benign and its natural history so favourable that the memory of the episode fades away. It is extremely interesting to note that among the few significant variables, those related to general well-being and self-perception of health, are prominent. It appears, therefore, that psychological factors play a role in the experience of LBP in a similar way to what has been reported in adults. Poor self-perception of health (health belief) could be a factor behind the reporting of LBP. Some variables linked to consequences of LBP (absence from school or from gym and visit to a doctor) play a significant role in reporting LBP, which suggests that those "health care" factors may reinforce a feeling of disease severity.

Sleepiness and recovery in schedule change and the eighty-four hour workweek

The aims were to evaluate sleepiness and recovery during a schedule change, and during an 84-hours workweek. The control group (16 men) stayed on a six-week schedule, whereas the intervention group (12 men) transferred to a seven-week schedule. Sleepiness was estimated, using the KSS-scale, four times during the first and the third night in the fifth or sixth shift week. Recovery was assessed through four estimations on days one, three and five during the week off. Statistical testing was carried out using repeated measurement ANOVA. Sleepiness at night was affected by night (F = 4.90, p < 0.05) and hour (F = 33.64, p < 0.001) in both groups. The intervention group was sleepier during the first recovery day compared to the control group (F = 4.02, p < 0.05). Analysis of the 84-hour-week showed an effect of night (F = 8.98, p < 0.05) and hour (F = 71.60, p < 0.001) on night work, and day (F = 22.49, p < 0.01) and hour (F = 6.66, p < 0.05) on recovery. Sleepiness was more pronounced on the first recovery day (F = 23.08, p < 0.01). The seven-week schedule showed no effect that differed from that of the control group on sleepiness during the night shift. After the 84-hour workweek the workers recovered in about three days. The new schedules may affect the first recovery day negatively.

Testing apparatus and experimental procedure for position specific normalization of electromyographic measurements of distal upper extremity musculature

OBJECTIVE

An apparatus and procedure are described to determine position specific normalization coefficients for surface EMG of upper extremity musculature.

STUDY DESIGN

Thirty-nine subjects were tested three times. Repeatability of EMG measurements across test sessions was determined by computing intraclass correlation coefficients. Two-way analysis of variance was used to test upper extremity position dependent differences in EMG measurements.

BACKGROUND

EMG measurements are susceptible to error from skin movement and muscle length changes, both of which may occur when upper extremity positions vary. Normalization of the EMG signal without consideration for such positional influences may lead to erroneous conclusions regarding muscle activation during functional tasks.

METHOD

An apparatus was designed that allowed subjects to perform three repetitions of maximum elbow flexion, forearm pronation, wrist extension, and wrist flexion with the forearm in neutral and pronated positions. Surface EMG was sampled from eight muscles. Mean EMG on maximum voluntary contraction was computed, and resting EMG was subtracted to obtain EMG normalization coefficients.

RESULTS

Upper extremity position affected the EMG normalization coefficient for biceps brachii, which was lower in the pronated position, and extensor carpi radialis, which was higher in the pronated position (P<0.00625).

CONCLUSIONS

The apparatus accommodates various combined positions of the elbow, forearm and wrist. The normalization procedure is efficient for testing subjects who are being observed during functional tasks. Only two muscles were affected by upper extremity position, but group trends were not always consistent with individual behavior. This method would ensure the use of appropriate EMG normalization coefficients regardless of individual variation.

RELEVANCE

This method is effective for normalizing EMG signals using task specific upper extremity positions. It may be used to test isometric exertions of distal upper extremity musculature for clinical and research purposes.

Recovery of impaired muscle function in severe sciatica

This is a prospective cohort study of patients with acute treated severe sciatica. The objectives of the study are, firstly, to describe the recovery of muscle performance by manual and isokinetic muscle testing in patients with acute severe sciatica over 1 year, and secondly, to discuss the potential clinical relevance of the isokinetic testing of the ankle for patients with acute sciatica. In clinical daily practice, muscle performance is evaluated by means of isometric manual tests. Different authors using manual muscle tests have reported the long-term outcome of the muscle function in patients with sciatica. Overall, the results are good in terms of the recovery of muscle strength. However, it is not clear whether the isometric strength is sufficiently relevant to evaluate the more complete muscle performance of the affected muscles in patients with sciatica. This study presents data on the muscle recovery measured with manual testing and isokinetic testing of patients with severe sciatica. Consecutive patients admitted to the Cantonal Hospital for conservative management of severe acute sciatica were eligible for inclusion in the study. Patients were evaluated at admission, discharge, and follow-up at 3, 6, and 12 months. All the visits included a standardized clinical examination and the completion of questionnaires. Imaging and electromyography were conducted at the first visit. Isokinetic muscle tests at 30 degrees/s and 120 degrees/s were performed at discharge and follow-up visits. Manual and isokinetic tests were performed on foot and ankle flexor and extensor muscles. Eighty-two consecutive patients (66% men), with a mean age of 43 (+/-10.3) years, entered the study. The prevalence of major muscle weakness was low, with 7% of patients unable to perform toe walking and 11% unable to walk on the heel at visit one. Moreover, motor deficit defined as a score of 4 or less (out of 5) was found in 15% of subjects at the first evaluation. Such severe deficits were not found during the last three visits. The isokinetic tests showed a higher prevalence of muscle function impairment. At visit 5, the isokinetic test showed impaired muscle function recovery from 23% to 32%, while the manual test showed almost full recovery. The issues of agreement between manual and isokinetic muscle testing are discussed. In this selected and homogeneous cohort of patients, the prevalence of motor deficit was rather low and the outcome excellent according to the results of the manual testing. Isokinetic muscle tests showed a higher prevalence of deficit and a much slower recovery. The manual muscle test is a crude clinical test. For more indepth muscle performance evaluation, additional testing may be necessary, especially for those patients with physically demanding jobs or activities.

The test-retest reliability of a new occupational risk factor questionnaire for outcome studies of low back pain

This study reports the test-retest reliability of a 25-item occupational risk factor questionnaire that can be self-administered in clinical settings and used in outcome studies of low back pain or return to work programs. Subjects were 24 patients (workers on sick leave due to acute low back pain), 29 co-workers on active duty in the same jobs in a utility company, and 53 supervisors. Eighty-six subjects were re-tested within a mean interval of 7-10 days; one group of 20 supervisors was re-tested within 81 days. The questionnaire was self-administered during individual interviews. Reliability was estimated by the kappa statistic as the agreement on the scores within the raters in each group. The agreement ranged from 'slight' (0.15) to 'almost perfect' (0.93) when the re-test interval was less than 43 days. Patients and non-patients were consistent in their assessment of the job demands. rights reserved.

Evaluation of the Abbott AxSYM cytomegalovirus (CMV) immunoglobulin M (IgM) assay in conjunction with other CMV IgM tests and a CMV IgG avidity assay

The measurement of the avidity of cytomegalovirus (CMV) immunoglobulin G (IgG) antibodies has been shown by several investigators to be useful in identifying and excluding primary CMV infections in pregnant women. In this work, we examined the diagnostic utility of reflex testing of CMV IgM-positive specimens from pregnant women by using a CMV IgG avidity assay. The utility of this approach was directly dependent on the sensitivity of the CMV IgM assay employed during the initial screen. The higher initial reactivity rate of the AxSYM CMV IgM assay was necessary in order to detect CMV IgM in specimens containing low-avidity CMV IgG antibodies, indicative of a primary CMV infection, which other CMV IgM assays (Behring, Vidas, Captia, and Eurogenetics) fail to detect in some cases. The use of the AxSYM CMV IgM assay, followed by an avidity test, should result in more accurate diagnosis of CMV infection in pregnant women.

[Cytostatic therapy reduces the immune defense. Children treated for leukemia have impaired immunity against measles and rubella]

A study is summarized analyzing the levels of serum antibodies against vaccination antigens in 43 children treated for acute lymphoblastic leukemia. Two different therapeutical regimens were used. All children had been immunized against measles and rubella before being diagnosed with leukemia. Eight of the 24 children treated 1986-1991 lacked protective levels of antibodies against measles; four of the 24 children lacked antibodies against rubella. In the second cohort of children (n = 16) treated from 1992 and onwards, nine lacked protective levels of antibodies against measles, eight lacked antibodies against rubella.

Low back pain in a population of school children

A study was undertaken to analyse the prevalence of low back pain (LBP) and confounding factors in primary school children in the city of Antwerp. A total of 392 children aged 9 were included in the study. All children completed a validated three-page questionnaire and they all underwent a specific lumbar spine oriented medical examination during their annual routine medical school control. This examination was performed by the city school doctors. The questionnaire was composed of easy "yes/no" questions and visual analogue scales. Statistical analysis was performed using Student's t-test and chi-squared test at the significance level P < 0.05. The prevalence of LBP was high. No gender difference was found. A total of 142 children (36%) reported having suffered at least one episode of LBP in their lives. Of these, 33 (23%) had sought medical help for LBP from a doctor or physiotherapist. Sixty-four percent of children reporting LBP said that at least one of their parents suffered from or complained of LBP. This was significantly higher than for the children who did not report having suffered LBP. The way in which the school satchel was carried (in the hand, on the back) had no bearing on the incidence of LBP. There was significantly more LBP in children who reported playing video games for more than 2 h per day, but this was not so for television watchers. The visual analogue scales concerning general well-being were all very significantly correlated with self-reported LBP, with children who reported LBP being more tired, less happy, and worse sleepers. Of the 19 clinical parameters taken down during the medical examination, only one was significantly more prevalent in the group of children reporting LBP: pain on palpation at the insertion site on the iliac crest of the ilio-lumbar ligament. From this study we can establish that there are few clinical signs that can help to single out school children with LBP.

Recovery of severe sciatica

STUDY DESIGN

A prospective study of patients with acute severe sciatica.

OBJECTIVES

To 1) describe the characteristics of patients with acute severe sciatica and the agreement among different diagnostic tests, 2) describe overall recovery during 1 year in terms of perceived disability, and pain, and 3) explore acute-phase predictors of failure to recover at 1 year.

SUMMARY OF BACKGROUND DATA

The development of imaging techniques has been very impressive during recent decades. However, different authors have highlighted the prevalence of abnormal images among asymptomatic subjects. These findings increase the difficulty of interpreting the results from the diagnostic techniques used with each individual patient. Furthermore, other clinical and biopsychosocial variables need to be explored for their associations with recovery or failure to recover. This study aimed to explore those associations.

METHODS

Consecutive patients admitted to the hospital for conservative management of severe acute sciatica were eligible for inclusion in the study. Patients were evaluated at admission, discharge, and 3, 6, and 12 months. All the visits included a standardized clinical examination and the completion of questionnaires that included items on demographics, pain, perceived disability, and quality of life. Imaging and blood samples were collected at the first visit, and an electromyogram was taken for sciatica lasting at least 3 weeks.

RESULTS

The study included 82 consecutive patients (66% men) with a mean age of 43 +/- 10.3 years. The mean intensity of pain, on a visual analog scale of 0 to 100 (VAS) at Visit 1, was 73. The straight leg raising test was positive in 78% of the patients, with a mean value of 59 degrees +/- 18 degrees. The contralateral straight leg raising test was positive in 20% of the patients. Imaging was positive for disc herniation in 74% and electromyogram was positive in 62% of cases. These two diagnostic tests showed a good to excellent total agreement (58-87%) with the straight leg raising tests and the presence of radiating pain below the knee. The recovery of clinical symptoms and signs was observed mainly within the first 3 months. However, clinical recovery and perceived recovery was not complete in most cases.

CONCLUSIONS

In most cases, there was good to excellent agreement among the different diagnostic tests. None of the tests was predictive of recovery. The presence of blood antibodies against 3'LM1 (IgM + IgG) and GD1a (IgM) was significantly associated (P < 0.023) with neurologic symptoms and signs. However, the meaning of these antibodies remains unclear. Only a minority of the patients (29%) had fully recovered after 12 months. Within the 1-year follow-up, one third of the patients had surgery.

Physical therapy: exercises and the modalities: when, what, and Why?

This article reviews the evidence for using modalities and/or exercise treatment in patients with nonspecific low back pain. Poor evidence of efficacy exists for the use of modalities in this patient group. Exercises are beneficial for patients with subacute and chronic nonspecific low back pain. Further studies are needed for type, frequency, duration, and intensity of exercises.

Postural after-contractions in man attributed to muscle spindle thixotropy

1. It is an old observation that non-volitional arm abduction movements accompanied by a sensation of arm lightness often occur as an after-effect following forceful voluntary arm abductor contractions against a restraint. In the present study we have tested the hypothesis that such non-volitional, so-called 'postural after-contractions' are tonic reflex responses to an enhanced resting discharge in primary muscle spindle afferents which in turn is a consequence of thixotropy-dependent enhanced stiffness of intrafusal muscle fibres. 2. Results obtained in ten volunteers show that the arm abductor after-contraction phenomenon in man is most readily evoked by a type of conditioning procedure which in various respects mimics the procedure proven in animal experiments to be particularly effective in producing thixotropy-dependent excitation of primary spindle endings. 3. It is also shown that changes in arm abductor intramuscular temperature affect the strength of the after-contractions in a direction predicted by the thixotropy hypothesis. 4. Attention is drawn to several similarities between the after-contraction phenomenon with accompanying sensory illusions and the tonic reflex responses and illusions that can be induced when primary spindle endings are excited by muscle vibration. 5. The results support our hypothesis that postural after-contractions are induced by activity in primary muscle spindle afferents as a consequence of thixotropic properties of intrafusal muscle fibres. Central excitability changes following the conditioning voluntary effort may contribute to the phenomenon.

Approaches to improve the outcome of patients with delayed recovery

The purpose of this chapter is to promote a model to prevent chronicity and disability from non-specific low back pain (NSLBP). Delayed recovery is defined in this chapter as the period between 4 and 8 weeks after onset of NSLBP during which a patient has not yet returned to work. The recognition of predictors associated with delayed recovery at onset of the problem helps health care providers in their treatment plan. An algorithm can be useful for health care providers and employers in guiding the employee back to work. A multidisciplinary return to work programme is an essential part of the algorithm.

Patient-health care provider relationship in patients with non-specific low back pain: a review of some problem situations

Problem situations in the patient-health care relationship may relate to the patient or to the health care provider characteristics or to the way they interact; they may also relate to the general social context. Such situations force the clinician dealing with non-specific low back pain patients to look beyond the traditional biomedical model that assumes a linear connection between pathology and symptomatology. The introduction of the biopsychosocial model approximately 10 years ago has improved the understanding of common low back pain. This chapter gives some insight into areas relating to factors that may hamper the patient-therapist relationship and thus complicate treatment and recommendation outcomes. It emphasizes the necessity to involve the patient in the decision-making. Recognizing the patients' psychological, social and cultural background as well as the level of education and employability are important to make successful recommendations. This knowledge is not new but the difficulty is to implement it in today's cost effectiveness driven society. However the benefit at the end may be the decrease of chronicity and/or permanent disability, suffering for the patient and frustration for the clinician. Identifying the underlying cause of non-compliance or of unexpected delayed recovery is an exciting issue. The cause may or may not be biomedical. If a specific cause can be identified, it has to be diagnosed and evaluated. If the clinical examination has ruled out specific or emergency conditions, another perspective may be needed and the course of action could then be determined.

Health care providers should use a common language in relation to low back pain patients

Uncertainty is the rule rather than the exception when it comes to the underlying causes of 'common' or 'non-specific' low back pain. It may be called many names, depending on whether the diagnostic term is descriptive, anatomopathological or physiopathological. Classifications have been devised, including various criteria: symptoms and signs, duration, treatment, consequences of low back pain on the patients' daily life, etc. Because back pain frequently runs a recurrent course, functional and pain outcomes need to be considered separately: chronic disability and chronic pain may not be parallel. Thus, pain duration (e.g. acute, transient, recurrent, chronic) is only one element in the definition of chronicity. These difficulties in defining and classifying non-specific low back pain may lead to communication problems among health professionals as well as between patients and health professionals. These difficulties raise questions such as: what kind of diagnostic term should we use to avoid dramatization of non-specific low back pain? how can we improve the definition of long-term low back pain? and how can we assure and reassure the patient that this condition is benign in the majority of the population?

Low back pain assessment training of industry-based physicians

We have developed an educational program to train industry-based physicians in a new low back pain assessment procedure based on the recommendation of The Clinical Practice Guidelines on Acute Low Back Pain Problems in Adults published by the Agency for Health Care Policy and Research, U.S. Department of Health and Human Services. The clinical classification system based on the findings from the Quebec Task Force was used to categorize the subjects. The educational program included group and individual sessions with an extensive period of active follow-up. Protocol compliance was measured through a computer-based surveillance system that monitored evaluation form completion. The results showed significant change (p < 0.001) in physician compliance in completing a standardized examination following an administrative mandate to change. Little change in clinical practice was recorded with an educational training program only. Further research into the factors responsible for the results is suggested.

Sympathetic vasoconstrictor outflow to extremity muscles in cluster headache. Recordings during spontaneous and nitroglycerin-induced attacks

To search for evidence of sympathetic dysregulation during cluster headache attacks, microneurographic recordings of muscle nerve sympathetic activity (MSA) were obtained from the peroneal nerve. In three recordings commenced after the onset of spontaneous attacks, MSA was about twice as high during the attack as afterwards. In four nitroglycerin-induced attacks, MSA showed a rise paralleling the pain, preceded by an initial peak. The latter accompanied hypotension, whereas the rise coinciding with cluster headache was associated with rising blood pressure. The normal baroreflex-governed pulse synchrony of MSA was preserved both during spontaneous and provoked attacks. In seven cluster headache patients in whom nitroglycerin did not cause an attack, only an initial peak in MSA occurred. Nor was any late nitroglycerin-induced rise in MSA observed in nine healthy subjects; the initial peak in MSA and heart rate was followed by a rapid return to normal despite a falling blood pressure. It is concluded that cluster headache attacks are associated with an increase in MSA that elevates blood pressure by causing vasoconstriction, and that this increase, rather than indicating sympathetic dysregulation, is a normal pain-evoked secondary phenomenon. The findings in healthy subjects support the notion that nitroglycerin has a central sympatho-inhibitory effect.

Effects of preceding movements and contractions on the tonic vibration reflex of human finger extensor muscles

The vibration sensitivity of feline muscle spindle endings is known to vary as a result of preceding muscle conditioning manoeuvres. If similar after-effects occur in man they should be expected to influence the strength of the tonic vibration reflex (TVR). To study this issue, vibration was applied over the finger extensor tendons of 11 volunteers who actively held their fingers in a semi-extended position. The TVR, measured as electromyographic responses and angular deflections at the metacarpophalangeal joints, was found to be stronger when the extensors prior to the test had been contracted in a shortened position than when they had been contracted in a stretched position. This difference was reduced when the vibration stimulus was preceded by a strong extensor contraction in the test position. The antigravity extensor EMG activity required to keep the fingers in the test position was weaker when the conditioning contraction was performed at a short muscle length than when it was performed at a long muscle length. The variations in magnitude of the TVR can be attributed to 'thixotropic' properties of intrafusal muscle fibres, resulting in a slack following conditioning at a long muscle length. The different EMG levels required for position holding can be explained by similar properties of extrafusal muscle fibres. In conclusion, the results demonstrate the importance of taking the 'history of movement' into account in the design of all TVR studies.

Physical exercise and low back pain

Health care providers often prescribe exercises as treatment for nonspecific low back pain. However, the effectiveness of this treatment is poorly documented in the literature. While the evidence suggests that exercise in general is beneficial, there is a lack of knowledge about the types, frequency and duration of exercises that should be prescribed and at what stage of injury they are most helpful. In addition, few studies have dealt with exercise treatment alone rather than in combination with other treatments, making it hard to decipher the unique contribution of exercise. Inadequate study designs also make conclusions difficult. Conversely, the literature clearly shows that inactivity has detrimental effects (i.e. delayed return to normal activity, and negative physiological and psychological effects) for low back pain patients.

Primary prevention, education, and low back pain among school children

After a survey in 1986, a primary educational prevention program for low back pain (LBP) was implemented over a 3 year period in a primary school setting in Switzerland. In 1989 a second survey was carried out to evaluate the effect of the intervention. One thousand seven hundred and fifty-five (1755) children received a questionnaire, 1716 (97.7%) were returned. Recollection of participation in the prevention program was significantly associated with reported increased prevalence of LBP (p 0.000). Simultaneously, there was a significant reduction in the utilization of medical care for LBP (p < 0.05).

Effect of noxious stimulation on sympathetic vasoconstrictor outflow to human muscles

1. In fifteen healthy volunteers, muscle nerve sympathetic activity (MSA) was recorded from the peroneal nerve using microneurography. Blood pressure and electrocardiogram were also recorded. 2. Painful stimuli, adjusted to the subject's tolerance level, were delivered over 30-60 s via (a) pressure to the nail-bed of different digits, and to the trigeminal region, (b) electrical stimulation (5 Hz) of digital nerves and of the supraorbital nerve, or (c) instillation of soap solution into one eye. Non-painful ocular pressure was also applied. 3. All procedures except electrical stimulation of digital nerves caused a marked increase in MSA (mean, 160-248%) with preserved pulse synchrony and a rise in blood pressure. Stimulation of digits induced tachycardia, whereas stimulation of the trigeminal region tended to cause bradycardia. 4. Despite similar pain ratings, electrical stimulation of digital nerves caused a smaller MSA response than the other stimuli (mean increase, 40%). 5. It is concluded that sustained noxious stimulation in awake humans evokes a generalized MSA increase; the activity is still under baroreflex control, but the inhibitory level is reset. Both spinal and brainstem reflexes may contribute; a defence reaction is an unlikely explanation. It is suggested that the number of afferent C fibres activated by electrical stimulation of digital nerves was insufficient to induce any marked MSA response. 6. The non-painful oculo-cardiac reflex is associated with a strong increase in MSA.

Preventive and promotive medicine in ambulatory clinical practice: a prospective simulated patient study

OBJECTIVE

This study examines the extent to which preventive and promotive advice is integrated into the clinical practice of doctors.

STUDY DESIGN

Using a cross-sectional descriptive survey design, the study compares the performance of doctors in giving healthy lifestyle advice for five clinical conditions, their perceived practice and their rating on the importance of disseminating selected key lifestyle messages.

DATA EXTRACTION METHODS

A total of 28 volunteers were trained to simulate the five clinical conditions which required related health advice and to rate the doctors' performance with the use of a prepared checklist. Simulated patient ratings of 343 doctor-patient encounters provided the data on doctors' health promotion efforts for the selected clinical conditions. A post-visit self-administered questionnaire survey of a sub-sample of 100 doctors gave an insight into their opinions and perceived practice.

PRINCIPAL FINDINGS

Only in 49% of the instances was a health promotion message given. The doctors' encouraging interest in health education and health promotion and their positive perceptions of their volume of healthy lifestyle counselling were not borne out in actual clinical practice.

CONCLUSIONS

The results indicate that the extent of preventive and promotive health education in both the public and private health sectors is unacceptably low. The matter needs to be addressed through training programmes as well as the formulation of clear health promotion priorities and strategies in Malaysia.

Back pain: lessons from patient education

Education for the patient with back pain is currently being discussed and reassessed. In the 1970s and 1980s, the clinical and scientific communities were convinced that patient education as a sole treatment for back pain was most beneficial. In the 1990s outcome studies, randomized controlled trials, meta analysis and best synthesis evidence have moderated this view. This brief overview summarizes important aspects put forward in recently published articles about the education of patients with non-specific, low back pain in industrialized societies.

Database analysis of injury patterns in an institution for developmental disabilities

This paper reports the results of a statistical analysis of injuries to the clients and the employees of a state facility for people with developmental disabilities, as recorded in the respective databases of the institution. The goal of the analysis was to identify the characteristics and patterns of injuries in order to identify priorities for technological intervention. Databases for 2000 client injuries and for 900 direct care staff injuries between 1988 and 1991 were analyzed retrospectively. Most of the injuries were sustained by the direct care staff and involved their backs. The injuries occurred in the institution's bedrooms (approximately 25%) and bathrooms (approximately 15%) and took place mainly during the early morning (approximately 30%) and evening rush (20%). The time of day and location of the injuries of clients coincided with those of the injuries of employees. These findings direct the focus of technological based interventions.

Reduced servo-control of fatigued human finger extensor and flexor muscles

1. In healthy human subjects holding the index finger semi-extended at the metacarpophalangeal joint against a moderate load, electromyographic (EMG) activity was recorded from the finger extensor and flexor muscles during different stages of muscle fatigue. The aim was to study the effect of muscle fatigue on the level of background EMG activity and on the reflex responses to torque pulses causing sudden extensor unloadings. Paired comparisons were made between the averaged EMG and finger deflection responses under two conditions: (1) at a stage of fatigue (following a sustained co-contraction) when great effort was required to maintain the finger position, and (2) under non-fatigue conditions while the subject tried to produce similar background EMG levels to those in the corresponding fatigue trials. 2. Both the unloading reflex in the extensor and the concurrent stretch reflex in the flexor were significantly less pronounced and had a longer latency in the fatigue trials. Consequently, the finger deflections had a larger amplitude and were arrested later in the fatigue trials. 3. It is concluded that--with avoidance of 'automatic gain compensation', i.e. reflex modifications attributable to differences in background EMG levels--the servo-like action of the unloading and stretch reflexes is reduced in fatigued finger extensor and flexor muscles.