title: Do psychosocial strain and physical exertion predict onset of low-back pain among nursing aides?
abstract: OBJECTIVE
  The aim of this study was to investigate psychosocial factors and physical exertion at work in relation to the onset of low-back pain.
  
  
  METHODS
  The study was carried out as a case-crossover investigation of nursing aides caring for the elderly. Cases were identified among 157 nursing aides over a period of 2 years. Psychosocial factors, physical exertion, and low-back pain were reported daily in diary questionnaires over three consecutive days at work, repeated in six periods of 3 days. For each subject, case observations were identified as pain onset from one day to the next and matched with reference observations with no pain onset from the same person. Prospective data collection allowed analyses to be conducted with and without a lag in time between exposure and pain onset.
  
  
  RESULTS
  The results of the analyses with time lag (longitudinal) did not support the hypothesis that psychosocial and physical strain from 1 day of work predicts pain onset the following day. However, physical exertion, stress, and, to some extent, time pressure were associated with pain on the day of onset.
  
  
  CONCLUSIONS
  The effect period, if any, of exposure to physical exertion, stress, and time pressure on the onset of acute low-back pain is considered to be less than 24 hours.
authors.affiliation: Department of Occupational Medicine, University Hospital of Aarhus and Institute of Psychology, University of Aarhus, Denmark. henrik@gonge.dk
authors.forename: H
authors.initials: H
authors.lastname: Gonge
authors.forename: L D
authors.initials: LD
authors.lastname: Jensen
authors.forename: J P
authors.initials: JP
authors.lastname: Bonde
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D018592:Cross-Over Studies; D003718:Denmark; D005260:Female; D006707:Homes for the Aged; D006801:Humans; D008137:Longitudinal Studies; D017116:Low Back Pain / Q000209:etiology* / Q000523:psychology; D008875:Middle Aged; D009728:Nursing Assistants; D009735:Nursing Homes; D009784:Occupational Diseases / Q000209:etiology* / Q000523:psychology; D016017:Odds Ratio; D005082:Physical Exertion; D012306:Risk; D018709:Statistics, Nonparametric; D013315:Stress, Psychological / Q000503:physiopathology*; D013997:Time Factors