Abstract
Background: Symptom modifying factors (SMFs) are everyday activities or postures that are reported to aggravate or alleviate existing LBP symptoms. In relation to sedentary jobs, workers are known to experience LBP whilst sat at work, and may report that aspects of sitting either aggravate or alleviate their symptoms. These factors appear to have received little attention in the literature, and may help to discriminate workers with different types of LBP, or identify workers likely to take sickness absence due to LBP.
Methods: A new sitting and symptom modifying factors questionnaire (SSMQ) was designed and consisted of 11 items. This questionnaire was distributed to 135 sedentary workers on two occasions with a 2 week time lapse. Principal components analysis (PCA) and Cronbach’s alpha were used to explore the structure and internal consistency of the questionnaire. Paired t-tests were used to determine test-retest stability.
Results: Three factors with eigenvalues > 1 were extracted that explained 62% of the total variance, and each factors items loaded > 0.06. These sub-scales related to aggravating and relieving (movement and posture) factors, and had consistency levels of 0.80, 0.72 and 0.78 respectively. The retest response rate was 46% and there were no statistically significant differences (p > 0.05) between test-retest measures.
Conclusions: Validating the SSMQ has produced an instrument that can be used in sedentary jobs to investigate the influence of symptom modifying factors on LBP symptoms, care seeking and sickness absence due to LBP. This questionnaire will now be used in a prospective study of sedentary call centre workers.
Correspondence should be addressed to: Mr John O’ Dowd, SBPR, c/o BOA, The Royal College of Surgeons, 35–43 Lincoln’s Inn Fields, London WC2A 3PE.
