The impact of psychosocial factors on low back pain: longitudinal results from the Belstress study

Psychosocial work stressors as antecedents of musculoskeletal problems: a systematic review and meta-analysis of stability-adjusted longitudinal studies

Although the relationship between psychosocial workplace conditions and musculoskeletal problems has been extensively studied, the causal impact of psychosocial workplace factors in the development of musculoskeletal problems remains unclear. The purpose of the present study was to conduct a systematic review of baseline-adjusted prospective longitudinal studies estimating the lagged effect of psychosocial risk factors on musculoskeletal problems in industrialized work settings. A literature review was conducted by searching the MEDLINE, EMBASE, and PsychINFO databases dated until August 2009. The authors classified studies into categories of psychological work stressors and musculoskeletal problems. Available effect sizes were converted to odds ratios (OR). ORs were then pooled for each stressor-problem relationship using a random-effects model. Additionally, the possibility of publication bias was assessed with the Duval and Tweedie nonparametric "trim and fill" procedure. In total, 50 primary studies fulfilled inclusion criteria. Within these studies at least five effect sizes were available for 23 of the 45 possible psychosocial work stress-musculoskeletal problems relationships, leaving 9 psychosocial variables and four musculoskeletal problem areas for analyses. Of these 23 relationships, pooled OR estimates were positive and significant ranging from 1.15 to 1.66 with the largest pooled OR estimating the relationship between highly monotonous work and lower back pain. The lagged effect of low social support on lower limb problems was the only effect size for which the statistical test for bias was significant. Most psychosocial stressors had small but significant lagged effects on the development of musculoskeletal problems. Thus, organizational interventions to minimize these stressors may be promising in reducing one risk factor for the development of employee musculoskeletal problems.

Trends in work-related musculoskeletal disorders: a comparison of risk factors for symptoms using quality of work life data from the 2002 and 2006 general social survey

OBJECTIVE

To assess trends in risk factors for work-related musculoskeletal disorders (MSDs).

METHODS

Results from two similar national surveys (2002 and 2006) examined trends in relationships between individual, psychosocial, and physical factors and MSDs.

RESULTS

Findings between years were similar, but important differences included a stronger effect of "Work Stress" on "Pain in Arms," and a stronger combined effect of "Hand Movement" and "Work Stress" on "Pain in Arms." Also, two interactions were statistically significant in the 2006 data, but not in the 2002 data, revealing potentially increased risks. These were "Hand Movement" and "Work Stress" on "Back Pain," and "Heavy Lifting" and "Work Stress" on "Pain in Arms."

CONCLUSION

New strategies for preventing both low back and upper extremity MSDs should focus on work stress, heavy lifting, and hand movement, individually and in combination.

Stop Using the Modified Work APGAR to Measure Job Satisfaction

Background. The psychometric properties of the Modified Work APGAR (MWA) scale are not established, yet researchers use this scale as an overall measure of job satisfaction. Objective. Perform psychometric analyses on the MWA scale using data from two populations. Methods. A landmark occupational cohort and a clinical cohort are populations with low back pain studied. The first five items of the MWA scale measure social support from coworkers, one item measures dissatisfaction with job tasks, and the sixth item measures lack of social support from a supervisor. Exploratory principal components analyses were conducted in both cohorts. Results. In both cohorts, the first five items of the MWA scale loaded consistently onto one factor, social support from coworkers subscale. Conclusions. Unless researchers are interested in measuring social support from coworkers only, future studies should use other reliable and valid instruments to measure a broad range of psychosocial work characteristics.

The incidence of low back pain in active duty United States military service members

STUDY DESIGN

Epidemiological study.

OBJECTIVE

To investigate the incidence and risk factors for developing low back pain in active duty military population to include age, sex, race, and rank, and military service.

SUMMARY OF BACKGROUND DATA

Low back pain is among the most common musculoskeletal conditions worldwide and is estimated to affect nearly two-thirds of the US population at some point in their lives. Low back pain is a multifactorial disease and many risk factors have been implicated including age, race, sex, and marital status.

METHODS

A query was performed using the US Defense Medical Epidemiology Database (DMED) for the International Classification of Diseases, Ninth Revision, Clinical Modification code for low back pain (724.20). 13,754,261 person-years of data were investigated. Multivariate Poisson regression analysis was used to estimate the rate of low back pain per 1000 person-years, whereas controlling for sex, race, rank, service, age, and marital status.

RESULTS

The overall unadjusted incidence rate of low back pain was 40.5 per 1000 person-years. Women, compared with men, had a significantly increased incidence rate ratio for low back pain of 1.45. The incidence rate ratio for the 40+ age group compared with the 20 to 29 years of age group was 1.28. With junior officers as the referent category, junior- and senior-enlisted rank groups had increased incidence rate ratio for low back pain, 1.95 and 1.35, respectively. Each service, when compared with the Marines as the referent category, had a significantly increased incidence rate ratio of low back pain: Army: 2.19, Navy: 1.02, and Air Force: 1.54. Compared with single service members, significantly increased incidence rate ratio for low back pain were seen in married service members: 1.21.

CONCLUSION

Female sex, enlisted rank groups, service in the Army, Navy, or Air Force, age greater than 40 years, and a marital status of married were all risk factors for low back pain.

Development of a risk score for low back pain in office workers--a cross-sectional study

Background

Low back pain (LBP) is common among office workers and is the most common cause of work-related disability in people under 45 years of age. The aetiology of LBP is widely accepted to be multi-factorial. Prognostic research into office workers at risk of developing LBP has received limited attention. The aims of this study were to develop a risk score to identify office workers likely to have LBP and to evaluate its predictive power.

Methods

397 office workers filled out a self-administered questionnaire and underwent physical examination. The questionnaire gathered data on individual, work-related physical and psychosocial data as well as the presence of low back pain in the previous 4 weeks. The physical examination included measurement of body weight, height, waist circumference, hamstrings length, spinal scoliosis, spinal curve, Backache Index and lumbar stability. Logistic regression was used to select significant factors associated with LBP to build a risk score. The coefficients from the logistic regression model were transformed into the components of a risk score.

Results

The model included six items: previous history of working as an office worker, years of work experience, continuous standing for >2 hrs/d, frequency of forward bending during work day, chair having lumbar support and Backache Index outcome. The risk score for LBP in office workers (The Back pain Risk score for Office Workers: The BROW) was built with a risk score ranging from 0 to 9. A cut-off score of ≥4 had a sensitivity of 80% and a specificity of 58%. The positive predictive value and negative predictive values were 70% each.

Conclusions

The BROW is easy and quick to administer. It appears to have reasonable sensitivity, specificity, positive predictive value and negative predictive values for the cut-off point of ≥4. The BROW is a promising tool for use to identify office workers in need of early interventions. Further prospective study is needed to validate the predictive performance of the BROW.

A Kangaroo Spine Lumbar Motion Segment Model: Biomechanical Analysis of a Novel In Situ Curing Nucleus Replacement Device

This in vitro study compared the effects of nucleotomy alone, with nucleotomy then implantation with a novel nucleus replacement device (D3 device) in a single segment kangaroo spine model. This study utilised dynamic biaxial biomechanical testing of intact, nucleotomy and nucleus replacement implant conditions to evaluate the kinematic behaviour of the single segment kangaroo lumbar spine. Studies have examined the biomechanical efficacy of invasive treatments such as Total Disc Replacement and Intervertebral Fusion for the treatment of chronic low back pain, however no studies to date have investigated the biomechanical effects of a novel elastomeric compressive load sharing nucleus replacement device. Kangaroo lumbar spine motion segments with all musculature, ligamentous tissue and posterior elements removed, were tested in intact state prior to undergoing nucleotomy or nucleotomy then nucleus implantation using the D3 device. All specimens were tested in flexion-extension and lateral-bending; Range of motion (ROM), Neutral Zone (NZ), Hysteresis (H), and Elastic Stiffness (ES) were evaluated. Nucleotomised motion segments demonstrated a 30% to 90% increase in ROM, NZ, H, but not ES for all Flexion-Extension testing conditions and in Lateral Bending test conditions when compared to intact state. Implantation of the nucleus replacement device demonstrated no significant difference when compared to intact state except for H during Lateral Bending testing conditions when compared to the intact state. Therefore, there was a significant increase in ROM, NZ, and H after Nucleotomy during Flexion-Extension motions and an increase in ROM alone during lateral bending motions in the single segment kangaroo spine model. These changes return to that of the intact state with the placement of a novel nucleus replacement device. Our data suggest that the D3 device tested can restore the kinematic changes of a degenerated disc represented by the nucleotomised single motion segment.

The relationship between lumbar spine kinematics during gait and low-back pain in transfemoral amputees

OBJECTIVE

Low-back pain is an important cause of secondary disability in transfemoral amputees. The primary aim of our study is to assess the differences in lumbar spine kinematics during gait between transfemoral amputees with and without low-back pain.

DESIGN

Lumbar spine kinematics in three planes were measured when the subjects walked in a motion analysis laboratory. Nine transfemoral amputees with low-back pain, eight transfemoral amputees without low-back pain, and six healthy, nonamputee subjects participated.

RESULTS

The Amputee Pain and Amputee No Pain groups were essentially the same in terms of all demographic and potentially confounding variable measures. Transfemoral amputees with low-back pain showed greater transverse plane rotational excursion in their lumbar spine during walking when compared with transfemoral amputees without low-back pain (P = 0.029; effect size = 1.03). There were no significant differences in sagittal or coronal plane lumbar spine excursions during walking between these two groups.

CONCLUSIONS

Although our study design does not allow for proving causation, increased transverse plane rotation has been associated with intervertebral disc degeneration, suggesting that increased transverse plane rotation secondary to walking with a prosthetic limb may be a causative factor in the etiology of low-back pain in transfemoral amputees. Identifying differences in lumbar motion can lead to potential preventative and therapeutic intervention strategies.

Purpose in Life among Men and Women Aged 85 Years and Older

The aim of this study was to investigate purpose in life in relation to psychological well-being, social relations, and physical and psychological symptoms among very old women ( n = 120) and men ( n = 69). Their purpose in life was evaluated using the Purpose in Life (PIL) scale. Women scored lower on this PIL scale than men (102 vs.108 p = .0.013). Regression analysis was used to estimate influencing factors on the PIL score. Determinants for purpose in life did not differ between the men and women, except for musculoskeletal symptoms. Attitude toward own aging had the strongest relation to PIL scores for both men and women; to have family to talk to was also important, as were musculoskeletal symptoms, for women. Our study indicates that the very old people studied were feeling indecisive about their purpose in life and that feelings are linked with poorer psychological health. For this reason, the purpose in life must be discussed and taken into consideration in the care of the elderly.

Risk factors for lumbar intervertebral disc herniation in Chinese population: a case-control study

STUDY DESIGN

A case-control study of 4180 subjects was carried.

OBJECTIVE

To explore the risk factors of lumbar disc herniation in China.

SUMMARY OF BACKGROUND DATA

In China, along with the economic development, people's living environment and working conditions have undergone some tremendous changes, such as the accelerating life pace and competition. In this situation, it is important to know whether the risk factors of lumbar disc herniation have changed or not. This case-control study, including the possible social and psychological factors based on the literature, attempted to search the new risk factor, therefore provide better prevention measures for lumbar disc herniation.

METHODS

A total of 2010 hospitalized patients, diagnosed with lumbar disc protrusion by CT and/or MRI were selected as cases. A total of 2070 people from communities and hospitals, without history of low back pain and sciatica, were selected as controls. All patients and controls were investigated for their family history, occupational characters' smoking status, working psychosocial factors, etc. The risk factors were analyzed by multiple nonconditional logistic regression method.

RESULTS

Family history (OR = 3.6) was the most important risk factor for lumbar disc protrusion in this study, followed by lumbar load (OR = 2.1), hard-working (OR = 1.8), and time urgency (OR = 1.1). Additionally, physical exercises (OR = 0.5) and bed characteristics (OR = 0.4) appeared to be the protective factors for lumbar disc protrusion. After stratified by age, family history (OR = 14.5), occupational character (OR = 5.2), and physical exercises (OR = 0.2) stronger association with lumbar disc protrusion was seen in subjects younger than 30 years. In subjects from 30 to 55 years, family history (OR = 5.1), lumbar load (OR = 1.91), hard-working (1.9), physical exercises (OR = 0.5), time urgency (OR = 1. 3), bed characteristics (OR = 0.4) were significantly important. In subjects older than 55 years, lumbar load (OR = 2.9) and bed characteristics (OR = 0.4) were closely related to lumbar disc protrusion.

CONCLUSION

Family history, lumbar load, hard-working, and time urgency are the major risk factors for lumbar disc herniation, and physical exercises and sleeping on the hard bed might be the protective factors.

Studying the relationship between low back pain and working postures among those who stand and those who sit most of the working day

A relationship between low back pain (LBP) and prolonged standing or prolonged sitting at work has not been clearly shown, despite its biological plausibility. Because sitting and standing postures vary as to duration and freedom to alternate postures, and standing postures vary as to mobility, associations between specific working postures and LBP were explored using multiple logistic regression. Associations between work factors and self-reported LBP during the previous 12 months that interfered with usual activities were examined among 4493 standing workers and 3237 sitting workers interviewed in the 1998 Quebec Health and Social Survey; 24.5% reported significant LBP. Since the same conditions can correspond to different physiological demands for sitting compared with standing workers, analyses were performed separately for the two groups. Standing without freedom to sit was associated with LBP. Different occupational physical and psychosocial factors were associated with LBP in sitting compared with standing populations.

Gender specificity in the prediction of clinically diagnosed depression. Results of a large cohort of Belgian workers

BACKGROUND

The recent increase in the incidence of clinical depression represents a major public health and socio-economical burden. Depression has its roots in both professional and private domains but few epidemiological studies have looked at predictors of long term clinical depression as defined by a sick-leave of 28 days or more and a diagnosis by a general practitioner in both genders.

OBJECTIVES

To study baseline predictors of long term spells of clinical depression within the framework of a large prospective study, the Belstress Study, in 6,659 men and 2,737 women aged 35-59 years at baseline survey.

METHODS

Kaplan-Meyer survival curves and Cox regression models were used in order to relate long term clinical depression defined by a sick-leave of 28 days or more to baseline socio-demographic and work and non-work variables.

RESULTS AND CONCLUSIONS

Density incidence of long term clinical depression is 0.5 years and 1.1/1,000 persons/months for men and women respectively. In univariate analyses specific gender predictors were observed as for men predictors besides level of education, were work related: high job-strain OR 1.67 (CI 95% 1.03; 2.71) and work dissatisfaction OR 1.78 (CI 95% 1.09; 2.91) whereas for women baseline predictors are related to private life dissatisfaction OR 1.84 (CI 95% 1.16; 2.91) and to a lesser degree low social support from co-workers OR 1.50 (CI 95% 0.93; 2.40). In both genders baseline severe depression symptoms defined by a CES-D score of percentile 90 or above is a predictor of long term sick-leave for clinical depression. In multivariate analyses, in a model without baseline CES-D high job-strain and job dissatisfaction remain independent predictors for incident clinical depression in men whereas only private life dissatisfaction remains a significant predictor in women. When added to the model CES-D is the most powerful predictor of clinical depression in both genders. Together with level of education, work dissatisfaction remains borderline significant in men whereas private life dissatisfaction remains an independent predictor for clinical depression in women. In men baseline symptoms of depression alleviate the impact of high job-strain on incident clinical depression whereas in women, private life dissatisfaction remains an independent predictor of clinical depression.

Towards a theory of chronic pain

In this review, we integrate recent human and animal studies from the viewpoint of chronic pain. First, we briefly review the impact of chronic pain on society and address current pitfalls of its definition and clinical management. Second, we examine pain mechanisms via nociceptive information transmission cephalad and its impact and interaction with the cortex. Third, we present recent discoveries on the active role of the cortex in chronic pain, with findings indicating that the human cortex continuously reorganizes as it lives in chronic pain. We also introduce data emphasizing that distinct chronic pain conditions impact on the cortex in unique patterns. Fourth, animal studies regarding nociceptive transmission, recent evidence for supraspinal reorganization during pain, the necessity of descending modulation for maintenance of neuropathic behavior, and the impact of cortical manipulations on neuropathic pain is also reviewed. We further expound on the notion that chronic pain can be reformulated within the context of learning and memory, and demonstrate the relevance of the idea in the design of novel pharmacotherapies. Lastly, we integrate the human and animal data into a unified working model outlining the mechanism by which acute pain transitions into a chronic state. It incorporates knowledge of underlying brain structures and their reorganization, and also includes specific variations as a function of pain persistence and injury type, thereby providing mechanistic descriptions of several unique chronic pain conditions within a single model.

Mental health effects of changes in psychosocial work characteristics: a prospective cohort study

OBJECTIVE

To explore a possible causal relationship between psychosocial work characteristics and mental health.

METHODS

Using longitudinal data from the Maastricht Cohort Study on "Fatigue at Work" (n = 2332), the effects of changes in job demands and decision latitude on subsequent changes in need for recovery and prolonged fatigue were studied.

RESULTS

Increasing job demands are a significant predictor of a subsequent increase in need for recovery (beta = 0.063) and prolonged fatigue (beta = 0.057). An increase in decision latitude predicted a subsequent decrease in need for recovery (beta = -0.078) and prolonged fatigue (beta = -0.063). After adjusting for changes in other work characteristics, the effects on changes in prolonged fatigue were no longer significant.

CONCLUSION

These findings support a possible causal relationship between work characteristics and mental health and can be used for designing effective prevention and intervention strategies.

Prevalence and risk factors associated with low back pain among health care providers in a Kuwait hospital

STUDY DESIGN

A cross-sectional survey among health professionals working in a Kuwait hospital.

OBJECTIVE

To investigate the prevalence and factors associated with low back pain (LBP).

SUMMARY OF BACKGROUND DATA

The literature suggests that health professionals are exposed to occupational risk factors that predispose them to developing LBP. These rates are not well established in Middle Eastern countries such as Kuwait.

METHODS

A self-administered survey was conducted with health professionals in an urban orthopedic hospital.

RESULTS

The response rate to the survey was 60% (n = 344). Lifetime prevalence of LBP in the sample was 70.9%, and point prevalence of LBP was 21.5%. Factors associated with acute LBP included direct patient contact (P = 0.015), performing patient lifts and/or transfers (P = 0.016), low job satisfaction (P = 0.039), and poor self-reported health status (P = 0.019). The prevalence ratio (PR) of reporting acute LBP was also found to increase as a function of the number of daily lifts/transfers performed (PR: 1.4; 95% CI: 1.27 to 1.70). Other factors generally associated with LBP, such as age, sex, professional experience, smoking and exercise, were not found to be significantly associated with LBP in this study.

CONCLUSION

No causal relationships can be inferred using these cross-sectional data. However, results suggest that direct patient contact that includes lifting and/or transferring patients may be an important risk factor. Further research is warranted to evaluate effectiveness of back education and prevention programs among hospital staff in Kuwait.

TTM-based motivational counselling does not increase physical activity of low back pain patients in a primary care setting--A cluster-randomized controlled trial

OBJECTIVE

To investigate the effectiveness of a TTM-based motivational counselling approach by trained practice nurses to promote physical activity of low back pain patients in a German primary care setting.

METHODS

Data were collected in a cluster-randomized controlled trial with three study arms via questionnaires and patient interviews at baseline and after 6 and 12 months. We analysed total physical activity and self-efficacy by using random effect models to allow for clustering.

RESULTS

A total of 1378 low back pain patients, many with acute symptoms, were included in the study. Nearly 40% of all patients reported sufficient physical activity at baseline. While there were significant improvements in patients' physical activity behaviour in all study arms, there was no evidence for an intervention effect.

CONCLUSION

The outcome may be explained by insufficient performance of the practice nurses, implementation barriers caused by the German health care system and the heterogenous sample.

PRACTICE IMPLICATIONS

Given the objective to incorporate practice nurses into patient education, there is a need for a better basic training of the nurses and for a change towards an organizational structure that facilitates patient-nurse communication. Counselling for low back pain patients has to consider more specificated aims for different subgroups.