Does the heritability of chronic low back pain depend on how the condition is assessed?

BACKGROUND: Although the influence of genetics on chronic low back pain (LBP) has been previously examined, few studies have investigated whether the impact of genetic factors on LBP depends on how the condition is assessed. METHODS: We investigated the contribution of genetics and environment on chronic LBP: lifetime prevalence, pain intensity (recent and worst) and activity limitation (anytime and recent) in a cross-sectional study with 1,598 adult twins. All twins answered a self-reported questionnaire about health-related questions. We conducted classic twin analyses using structural equation models to estimate the genetic and environmental influences in LBP phenotypes. RESULTS: We found a heritability of 26% (95%CI: 0.09-0.42) for lifetime chronic LBP; 36% (95%CI: 0.18-0.52) and 25% (95%CI: 0.03-0.46) for activity limitation due to chronic LBP, related to lifetime and most recent episode, respectively; and heritability of 35% (95%CI: 0.11-0.55) for pain intensity associated with the most recent episode. Genetics showed no significant influence in pain intensity experienced during the worst LBP episode. CONCLUSIONS: Genetic factors appear to significantly contribute to the variance in chronic LBP including lifetime chronic LBP, activity limitation and pain intensity associated with more recent episodes of LBP, but not for pain intensity associated with people's report of the worst pain episode. Heritability estimates was fairly similar across different LBP outcomes in a population-based twin sample, and not dependent on how it is assessed or experienced. However, we could not detect any significant heritability for a report of intensity experienced during the worst LBP episode experienced. SIGNIFICANCE: Heritability estimates were similar for different low back pain definitions, and therefore not dependent on how chronic low back pain is experienced or assessed, in the same population-based sample.

Comparative efficacy and safety of surgical and invasive treatments for adults with degenerative lumbar spinal stenosis: protocol for a network meta-analysis and systematic review.

INTRODUCTION: Surgical and invasive procedures are widely used in adults with degenerative lumbar spinal stenosis when conservative treatments fail. However, little is known about the comparative efficacy and safety of these interventions. To address this, we will perform a network meta-analysis (NMA) and systematic review to compare the efficacy and safety of surgical and invasive procedures for adults with degenerative lumbar spinal stenosis. METHODS AND ANALYSIS: We will include randomised controlled trials assessing surgical and invasive treatments for adults with degenerative lumbar spinal stenosis. We will search AMED, CINAHL, EMBASE, the Cochrane Library and MEDLINE. Only English studies will be included and no restriction will be set for publication status. For efficacy, our primary outcome will be physical function. Secondary outcomes will include pain intensity, health-related quality of life, global impression of recovery, work absenteeism and mobility. For safety, our primary outcome will be all-cause mortality. Secondary outcomes will include adverse events (number of events or number of people with an event) and treatment withdrawal due to adverse effect. Two reviewers will independently select studies, extract data and assess the risk of bias (Revised Cochrane risk-of-bias tool for randomized trials) of included studies. The quality of the evidence will be evaluated through the Grading of Recommendations Assessment, Development and Evaluation framework. Random-effects NMA will be performed to combine all the evidence under the frequentist framework and the ranking results will be presented through the surface under the cumulative ranking curve and mean rank. All analyses will be performed in Stata and R. ETHICS AND DISSEMINATION: No ethical approval is required. The research will be published in a peer-reviewed journal. PROSPERO REGISTRATION NUMBER: CRD42018094180.