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Identification of Risk Factors for New-Onset Sciatica in Japanese Workers: Findings From the Japan Epidemiological Research of Occupation-Related Back Pain Study

Matsudaira, Ko MD, PhD*; Kawaguchi, Mika MSc; Isomura, Tatsuya MSc†,‡; Arisaka, Mayumi*; Fujii, Tomoko MD, MDH*; Takeshita, Katsushi MD, PhD§; Kitagawa, Tomoaki MD, PhD; Miyoshi, Kota MD, PhD; Konishi, Hiroaki MD, PhD

doi: 10.1097/BRS.0000000000000003

Study Design. Two-year, prospective cohort data collected for the Japan epidemiological research of Occupation-related Back pain study were used for the analysis.

Objective. To identify potential risk factors for the development of new-onset sciatica in initially symptom-free Japanese workers with no history of sciatica.

Summary of Background Data. Although the associations between individual and occupational factors and cases of new-onset sciatica are established, the effect of psychosocial factors on the development of sciatica has still not been adequately clarified.

Methods. In total, 5310 participants responded to a self-administered baseline questionnaire (response rate: 86.5%). Furthermore, 3194 (60.2%) completed both 1- and 2-year follow-up questionnaires. The baseline questionnaire assessed individual characteristics, ergonomic work demands, and work-related psychosocial factors. The outcome of interest was new-onset sciatica with or without low back pain during the 2-year follow-up period. Incidence was calculated for participants who reported no low back pain in the preceding year and no history of lumbar radicular pain (sciatica) at baseline. Logistical regression assessed risk factors associated with new-onset sciatica.

Results. Of 765 eligible participants, 141 (18.4%) reported a new episode of sciatica during the 2-year follow-up. In crude analysis, significant associations were found between new-onset sciatica and age and obesity. In adjusted analysis, significant associations were found for obesity and mental workload in a qualitative aspect after controlling for age and sex. Consequently, in multivariate analysis with all the potential risk factors, age and obesity remained statistically significant (odds ratios: 1.59, 95% confidence interval: 1.01–2.52; odds ratios: 1.77, 95% confidence interval: 1.17–2.68, respectively).

Conclusion. In previously asymptomatic Japanese workers, the risk of developing new-onset sciatica is mediated by individual factors. Our findings suggest that the management of obesity may prevent new-onset sciatica.

Level of Evidence: 3

We sought to identify risk factors associated with new-onset sciatica in previously asymptomatic Japanese workers with no history of sciatica. Results indicated that individual factors mediated the risk of developing new-onset sciatica. In particular, the management of obesity may prevent cases of new-onset sciatica.

*Clinical Research Center for Occupational Musculoskeletal Disorders, Kanto Rosai Hospital, Kanagawa, Japan;

Clinical Study Support, Inc., Chikusa-ku, Nagoya Japan

Division of Clinical Research Consultation, Institute of Medical Science, Tokyo Medical University, Japan

§Department of Orthopaedic Surgery, the University of Tokyo, Tokyo, Japan

Department of Orthopaedic Surgery, Yokohama Rosai Hospital, Yokohama, Japan; and

Department of Orthopaedic Surgery, Nagasaki Rosai Hospital, Nagasaki, Japan.

Address correspondence and reprint requests to Ko Matsudaira, MD, PhD, Clinical Research Center for Occupational Musculoskeletal Disorders, Kanto Rosai Hospital, 1-1 Kizukisumiyoshicho, Nakahara-ku, Kawasaki 211-8510, Japan; E-mail:

Acknowledgment date: October 30, 2013. First revision date: July 12, 2013. Second revision date: August 23, 2013. Acceptance date: August 24, 2013.

The manuscript submitted does not contain information about medical device(s)/drug(s).

Dissemination project on the 13 fields of occupational injuries and illness of the Japan Labor Health and Welfare Organization grant funds were received to support this work.

Relevant financial activities outside the submitted work: grant.

© 2013 by Lippincott Williams & Wilkins