Temporal relationships between job strain and low-back pain

• Published in: Scandinavian Journal of Work, Environment ＆ Health Environment ＆ Health, 2017-09, Vol.43 (5), p.396-404
• Main Authors: Hanson, Linda L Magnusson, Madsen, Ida EH, Rugulies, Reiner, Peristera, Paraskevi, Westerlund, Hugo, Descatha, Alexis
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Back pain; Children; Cohort Studies; cross-lagged panel analysis; Employment status; Environmental factors; Female; fixed effect; Genetics; Health surveys; Humans; Invariants; job strain; Job stress; Longitudinal Studies; longitudinal study; Low back pain; Low Back Pain - etiology; Male; Men; Middle Aged; Occupational Health; Occupational stress; Pain; psychosocial work environment; Public health; Questionnaires; Risk analysis; Risk Factors; Sprains and strains; Statistical analysis; Stress, Psychological - psychology; structural equation modeling; Studies; Surveys and Questionnaires; Sweden; temporal relationship; Time Factors; Time lag; Variable coefficients; Variables; Work environment; work stress; Working conditions; Workload - psychology
• ISSN: 0355-3140; 1795-990X; 1795-990X
• DOI: 10.5271/sjweh.3654

Objectives: Psychosocial working conditions are suggested risk factors for low-back pain, but it is unclear whether these associations are causal. The present study examined whether there are lagged and bidirectional associations between job strain and low-back pain and further controlled for unmeasured time-invariant confounding. Methods: The study was based on four biennial waves of data from the Swedish Longitudinal Occupational Survey of Health (SLOSH), including 3084 men and women. Cross-lagged analyses using structural equation modeling (SEM) were conducted on job strain, a combination of high job demands and low control, and any as well as low-back pain severity (how much any problems affected the respondents life). Analogous SEM (dynamic panel) models with fixed effects were also fitted to remove confounding from time-invariant factors (such as non-observed individual and environmental factors, eg, genetics, childhood conditions, personality). Results: The SEM models indicated bidirectional associations between job strain and any back pain over a 2-year time lag (β=0.21 and 0.19, P＜0.05), when adjusting for a range of covariates. Job strain was also associated with an increase in low-back pain severity and vice versa. However, the SEM models with fixed-effects showed no statistically significant lagged relationships between job strain and any or low-back pain severity (β=-0.05 and β=0.00, respectively). Conclusions: This study suggests that associations between job strain and low-back pain with a lag of years may be due to residual confounding by time invariant characteristics. Further studies are, however, needed to elucidate short-term relationships.