2016-02-01 12:00 - Messages

Cortisol, Health, and Coping in Patients with Nonspecific Low Back Pain

Subjective health complaints (SHC), including nonspecific low back pain (LBP) as the most common single complaint, are the main reasons for long-term sick leave in many western countries. These complaints are often attributed to “stress”. Cortisol has frequently been considered a biomarker reflecting sustained physiological HPA-axis activity, and is characterized by a high cortisol awakening response (CAR) and low evening values. The aim of the study was to investigate whether LBP patients had a normal characteristic cortisol profile, and whether possible deviations were related to coping and health. 305 patients on long-term sick leave for LBP participated in the study, and saliva cortisol profiles were compared to a reference population consisting of Danish workers. Cortisol was measured upon awakening, after 30 min, and in the evening. Additionally, patients answered questionnaires about SHC, fatigue, pain, coping, and social support. The patients showed a seemingly normal cortisol profile. However, CAR was larger among patients compared to the reference population. Patients with low cortisol reactivity had more SHC, pain, and fatigue, and those with higher evening cortisol reported higher scores on coping. The results are discussed in terms of theory, practical considerations, and possible mechanisms for the association between cortisol, health, and coping.

Source: Sveinsdottir V, Eriksen HR, Ursin H, et al. Applied Psychophysiology and Biofeedback, March 2016, Volume 41, Issue 1, p.p 9-16.

Physical workload and risk of long-term sickness absence in the general working population and among blue-collar workers

Prospective cohort study with register follow-up
Objective: To determine the prospective association between physical workload—in terms of specific physical exposures and the number of exposures—and long-term sickness absence (LTSA).
Methods: Using cox-regression analyses, we estimated the risk of register-based incident LTSA (at least 3 consecutive weeks) from self-reported exposure to different physical workloads among 11 908 wage earners from the general working population (Danish Work Environment Cohort Study year 2000 and 2005).
Results: The incidence of LTSA was 8.9% during two-year follow-up. Spending 25% or more of the total work time with a bent or twisted back (HR 1.59 (95% CI 1.39 to 1.83)), arms above shoulder height (HR 1.35 (95% CI 1.14 to 1.59)), squatting or kneeling (HR 1.30 (95% CI 1.09 to 1.54)), pushing/pulling or lifting/carrying (HR 1.40 (95% CI 1.22 to 1.62)) and standing in the same place for 50% or more of total work time (HR 1.19 (95% CI 1.00 to 1.42), were risk factors for LTSA when adjusted for baseline age, gender, psychosocial work environment, lifestyle, musculoskeletal and mental disorders, and socioeconomic status. HR increased from 1.25 (95% CI 1.04 to 1.51) for one to 1.94 (95% CI 1.56 to 2.41) for four combined physical workloads. Results largely remained stable in subgroup analyses including only blue-collar workers (n=5055). Population attributable risks for LTSA from one or more physical workloads were 26% and 40% in the general working population and among blue-collar workers, respectively.
Conclusions: Several of the investigated types of physical workload were risk factors for LTSA when exceeding 25% of the work time. A higher number of combined physical workloads was associated with progressively increased risk. Our study underscores the importance of physical workload as risk factors for LTSA in the general working population as well as among blue-collar workers.

Source: Lars Louis Andersen, Nils Fallentin, Sannie Vester Thorsen, Andreas Holtermann. Occup Environ Med, 2016. 

Prevention of Low Back Pain

A Systematic Review and Meta-analysis
IMPORTANCE: Existing guidelines and systematic reviews lack clear recommendations for prevention of low back pain (LBP).
OBJECTIVE: To investigate the effectiveness of interventions for prevention of LBP.
DATA SOURCES: MEDLINE, EMBASE, Physiotherapy Evidence Database Scale, and Cochrane Central Register of Controlled Trials from inception to November 22, 2014.
STUDY SELECTION: Randomized clinical trials of prevention strategies for nonspecific LBP.
DATA EXTRACTION AND SYNTHESIS: Two independent reviewers extracted data and assessed the risk of bias. The Physiotherapy Evidence Database Scale was used to evaluate the risk-of-bias. The Grading of Recommendations Assessment, Development, and Evaluation system was used to describe the quality of evidence.
MAIN OUTCOMES AND MEASURES: The primary outcome measure was an episode of LBP, and the secondary outcome measure was an episode of sick leave associated with LBP. We calculated relative risks (RRs) and 95% CIs using random-effects models.
RESULTS: The literature search identified 6133 potentially eligible studies; of these, 23 published reports (on 21 different randomized clinical trials including 30?850 unique participants) met the inclusion criteria. With results presented as RRs (95% CIs), there was moderate-quality evidence that exercise combined with education reduces the risk of an episode of LBP (0.55 [0.41-0.74]) and low-quality evidence of no effect on sick leave (0.74 [0.44-1.26]). Low- to very low-quality evidence suggested that exercise alone may reduce the risk of both an LBP episode (0.65 [0.50-0.86]) and use of sick leave (0.22 [0.06-0.76]). For education alone, there was moderate- to very low-quality evidence of no effect on LBP (1.03 [0.83-1.27]) or sick leave (0.87 [0.47-1.60]). There was low- to very low-quality evidence that back belts do not reduce the risk of LBP episodes (1.01 [0.71-1.44]) or sick leave (0.87 [0.47-1.60]). There was low-quality evidence of no protective effect of shoe insoles on LBP (1.01 [0.74-1.40]).
CONCLUSION AND RELEVANCE: The current evidence suggests that exercise alone or in combination with education is effective for preventing LBP. Other interventions, including education alone, back belts, and shoe insoles, do not appear to prevent LBP. Whether education, training, or ergonomic adjustments prevent sick leave is uncertain because the quality of evidence is low.

Source: Steffens D, Maher CG, Pereira LS, Stevens ML2, Oliveira VC, Chapple M, Teixeira-Salmela LF, Hancock MJ. JAMA Intern Med. 2016 Feb 1; 176 (2): 199-208.

Social support modifies association between forward bending of the trunk and low-back pain

Cross-sectional field study of blue-collar workers
Objectives: This study aimed to investigate the association between forward bending of the trunk and low-back pain intensity (LBPi) among blue-collar workers in Denmark as well as whether the level of social support modifies the association.
Methods: In total, 457 workers were included in the study. The forward bending of ≥30° was computed from accelerometer recordings for several consecutive days during work, categorized into long (highest tertile) and short–moderate (remaining tertiles) duration. LBPi was measured on a 0–10 scale and categorized into low (≤5) and high (>5) pain. Self-reported social support was categorized into low, moderate, and high levels. Multi-adjusted logistic regressions estimated the association between forward bending and LBPi and the effect modification by social support.
Results: Forward bending and LBPi were not significantly associated but modified by social support. Workers with low social support and long duration of forward bending had higher likelihood of high LBPi [odds ratio (OR) 2.97, 95% confidence interval (95% CI) 1.11–7.95] compared to workers with high social support and long duration of forward bending. Among workers with low social support, workers with long duration of forward bending had higher likelihood of high LBPi (OR 3.28, 95% CI 0.99–10.90) compared to workers with short–moderate duration of forward bending. Among workers with high social support, workers with short duration of forward bending had reduced likelihood of high LBPi (OR 0.39, 95% CI 0.16–0.95) compared to workers with short–moderate duration of forward bending.
Conclusions: Social support modifies the association between objectively measured forward bending and LBPi among blue-collar workers.

Source: Villumsen M, Holtermann A, Samani A, Madeleine P, Jørgensen MB. Scand J Work Environ Health, 2016.

Biomechanical risk assessment during field loading of hydraulic stretchers into ambulances

The process of loading a stretcher into an ambulance is known to cause a high incidence of back injuries among paramedics. This study aimed to assess the forces at L5/S1 during real-life stretcher loading activities and to determine the variables that contribute significantly to these forces. Analyses involved 58 paramedics (111 shifts) and 175 stretcher loading activities. Estimates of compression and shear forces at L5/S1 were calculated using the 3DSSPP program. Seventy-one percent of loading activities exceeded the safe loading level of 3.4 kN compression force at L5/S1 (mean: 3.9 kN, min–max: 2.1–7.0 kN). About 92% of the variance can be predicted from a combination of several variables, notably hand load (mean: 0.72 kN/number of paramedics) and back sagittal flexion (mean: 32°). Recommendations to reduce the risk of back injuries are proposed with regard to stretcher and ambulance loading design as well as training in stretcher lifting for paramedics.

Source: Prairie, Jérôme, Plamondon, André, Hegg-Deloye, Sandrine, Larouche, Dominique, & Corbeil, Philippe. (2016). Industrial Journal of Industrial Ergonomics, 54, 1-9.

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