SITTING POSTURES AT WORK ARE ASSOCIATED WITH CURRENT AND FUTURE LBP

Abstract

Introduction: Systematic reviews have found that sitting at work is not associated with LBP, although the biomechanical evidence does offer plausible causative mechanisms. Indeed, exposure to lumbar postures has been assessed using imprecise tools that have limited epidemiological investigations. The aim of this study was to use new technology to measure the seated lumbar postures of sedentary (call centre) workers, and survey their current and future symptoms in order to determine associations with LBP.

Methods: A fibre-optic goniometer (FOG) system was attached to the lumbar spine and hip of 181 sedentary call centre workers at the start of their working shift. The lumbar FOG provides a continuous measure of sagittal lumbar curvature (lumbar position and movement), whilst the hip FOG enables quantification of sitting time. Baseline and 6-month follow-up questionnaires were used to collected symptom data, and logistic regression was used to determine associations between postural and symptom (yes/no) data.

Results: Workers spent a mean proportion of 83% of work-time sitting, with 17% sitting for more than 90 minutes without a break. Current LBP (symptoms lasting more than 24hrs) was associated with a kyphotic (mean lumbar angle> 180°) sitting posture (yes/no) (OR 2.1, 1.1–4.1), although movement (mean standard deviation and angular velocity °sec-1) in sitting was not. Sitting relatively static (AV< 4.26° yes/no) (OR 3.30, 1.06–10.25), using a small amount of range (SD< 10.2° yes/no) (OR 3.79, 1.2–11.7), and adopting a kyphotic posture (yes/no) (OR 2.75, 1.02–7.3) all significantly increased the risk of future LBP.

Discussion: Sitting postures at work are associated with current LBP and are statistically significant risks for recurrence. These results highlight the potential for ergonomic interventions to reduce current symptoms and the risk of future episodes. The findings from this study are novel, and the FOG system should now be used in larger investigations of sedentary risk factors for LBP.