Can We Trust the Literature on Risk Factors and Triggers for Low Back Pain? A Systematic Review of a Sample of Contemporary Literature

Interrelationships between job demands, low back pain and depression: A four-way decomposition analysis of direct and indirect effects of job demands through mediation and/or interaction

BACKGROUND

Psychosocial work stressors may lead to low back pain (LBP) through depressive symptoms or to depression through LBP. Depressive symptoms or LBP may also modify these associations.

METHODS

We examined prospective interrelationships between job demands, LBP and depressive symptoms. We used comparable data from three consecutive biennial surveys in 2010-2016, from the Swedish Longitudinal Occupational Survey of Health (SLOSH) and the Work Environment and Health in Denmark (WEHD) cohorts, broadly representative of the working populations in Sweden and Denmark. We conducted multivariate counterfactual based mediation analyses allowing for four-way decomposition of the total effect of job demands, on incident LBP (N=2813, 2701) and incident major depression (N=3707, 5496). The four components estimated direct and indirect effects through mediation and/or interaction.

RESULTS

We observed no association between job demands and incident LBP four years later, but job demands was associated with later major depression (relative risks=1.88, 95% confidence interval=1.45-2.31 in SLOSH and 1.64, 1.18-2.11 in WEHD, adjusted for age, sex, panel (SLOSH data), education, cohabitation, physically strenuous work and chronic diseases. About 37% of the association was attributed to interaction between job demands and LBP in SLOSH. No interaction was found in WEHD. LBP partly mediated the relationship, by 14% in SLOSH and 2%, while statistically insignificant in WEHD.

LIMITATIONS

Possible limitations include lack of comparable data on disabling low back pain, different scales for depressive symptoms, misclassification and residual confounding.

CONCLUSIONS

This suggests mainly a direct effect of job demands on major depression, or through other pathways than LBP.

The prognostic merit of self-reported triggers of recurrent low back pain: study protocol

Background

Most cases of low back pain (LBP) are regarded as non-specific and current studies indicate that for many this is a chronic recurrent condition, in which people experience episodes of pain with symptom-free periods in between. It is likely that acute exposure to some factors triggers the reappearance of new episodes in recurrent LBP regardless of the causality of the underlying condition (i.e. risk factors). Additionally, it has been shown that LBP patients present with different trajectories and different trajectories possibly have different triggers. Hence, dividing patients into some clinically meaningful subgroups may offer new insights into triggers, effective preventive strategies and, therefore, prognosis. This study aims to identify self-reported triggers and trajectories of episodes of recurrent LBP and to examine the prognostic association between different triggers and LBP trajectories.

Methods

This is a longitudinal, multicentre, Australia-wide observational study of patients with recurrent non-specific LBP. Two hundred adults with at least a one-year history of LBP will be recruited from primary care clinics or private practices and followed for a year. Each will receive an SMS every fortnight (26 time-points in total) enquiring the occurrence of a new episode of pain in the past 2 weeks and its intensity. Upon report of a new episode, a telephone interview will be performed to appraise exposure to self-nominated triggers in a period of 24 h preceding the pain. Trajectories will be identified by latent class analysis at the end of the follow-up based on the pain intensity, frequency, and length of episodes. Triggers will be categorised into physical and psychosocial groups. Generalised linear mixed models with logit links will be used to explore pain triggers associated with pain trajectories.

Discussion

The completion of this study will provide insight into the patients' self-reported triggers of LBP and also their possible prognostic association with different trajectories. Some newly-identified and pre-identified triggers are likely to be found and reported.

The Quebec Low Back Pain Study: a protocol for an innovative 2-tier provincial cohort

INTRODUCTION

The neurobiological mechanisms underlying recovery from or persistence of low back pain (LBP) remain misunderstood, limiting progress toward effective management. We have developed an innovative two-tier design to study the transition from acute to chronic LBP. The objective of the first tier is to create a provincial web-based infrastructure to recruit and monitor the trajectory of individuals with acute LBP. The objective of the second tier is to fuel hypothesis-driven satellite data collection centers with specialized expertise to study the role of biomechanical, epigenetic, genetic, neuroanatomical, ontological, physiological, psychological, and socioeconomic factors in LBP chronicity.

METHODS

This article describes the first tier of the protocol: establishment of the Core Dataset and Cohort. Adults with acute LBP will be recruited through networks, media, and health care settings. A web-based interface will be used to collect self-reported variables at baseline and at 3, 6, 12, and 24 months. Acute LBP will be defined according to the Dionne 2008 consensus. Measurements will include the Canadian minimum data set for chronic LBP research, DN4 for neuropathic pain, comorbidities, EQ-5D-5L for quality of life, and linkage with provincial medico-administrative databases. The primary outcome will be the transition to chronic LBP, as defined by Deyo 2014. Secondary outcomes include health care resource utilization, disability, sick leave, mood, and quality of life.

PERSPECTIVE

This study brings together diverse research expertise to investigate the transition from acute to chronic LBP, characterize the progression to recovery or chronicity, and identify patterns associated with that progression.