Article

Lumbar disk degeneration (LDD) has been related to heavy physical
loading. However, the quantification of the exposure has been controversial, and
the dose-response relationship with the LDD has not been established.
The purpose of this study was to investigate the dose-response relationship
between lifetime cumulative lifting load and LDD. DESIGN: This was a
cross-sectional study. METHODS: Every participant received assessments with a
questionnaire, magnetic resonance imaging (MRI) of the lumbar spine, and
estimation of lumbar disk compression load. The MRI assessments included
assessment of disk dehydration, annulus tear, disk height narrowing, bulging,
protrusion, extrusion, sequestration, degenerative and spondylolytic
spondylolisthesis, foramina narrowing, and nerve root compression on each lumbar
disk level. The compression load was predicted using a biomechanical software
system. RESULTS: A total of 553 participants were recruited in this study and
categorized into tertiles by cumulative lifting load (ie, <4.0 x 10(5), 4.0 x
10(5) to 8.9 x 10(6), and >/=8.9 x 10(6) Nh). The risk of LDD increased with
cumulative lifting load. The best dose-response relationships were found at the
L5-S1 disk level, in which high cumulative lifting load was associated with
elevated odds ratios of 2.5 (95% confidence interval [95% CI]=1.5, 4.1) for
dehydration and 4.1 (95% CI=1.9, 10.1) for disk height narrowing compared with
low lifting load. Participants exposed to intermediate lifting load had an
increased odds ratio of 2.1 (95% CI=1.3, 3.3) for bulging compared with low
lifting load. The tests for trend were significant. LIMITATIONS: There is no
"gold standard" assessment tool for measuring the lumbar compression load.
CONCLUSIONS: The results suggest a dose-response relationship between cumulative
lifting load and LDD.
CI - (c) 2014 American Physical Therapy Association.

Langue : ANGLAIS