[General Spine] Challenging the cumulative injury model: positive effects of greater body mass on disc degeneration

[Justin]

Challenging the cumulative injury model: positive effects of greater body mass on disc degeneration

The Spine Journal
Volume 10, Issue 1, Pages 26-31 (January 2010)

Tapio Videman, MD, PhDab, Laura E. Gibbons, PhDc, Jaakko Kaprio, MD, PhDbde, Michele C. Battié, PhDab

a The Finnish Twin Cohort Study, Department of Public Health, University of Alberta, Edmonton T6G 2G4, Canada
b The Finnish Twin Cohort Study, Department of Public Health, University of Helsinki, Helsinki 00014, Finland
c Department of General Internal Medicine, University of Washington, Seattle, WA 98195, USA
d Department of Mental Health and Alcohol Research, National Public Health Institute, Helsinki 00300, Finland
e Institute of Molecular Medicine, University of Helsinki, Helsinki 00014, Finland. © 2010 Elsevier Inc. All rights reserved.

Background context

There are differing views as to the causes of disc degeneration. One view, referred to as a cumulative or repetitive injury model, explains disc degeneration, in great part, as the result of “wear and tear” on the disc from routine daily exposures to physical loading or biomechanical forces. Perhaps paradoxically, such physical loading has been thought to be generally beneficial for other structures of the musculoskeletal system.

Purpose

The goal of this study was to investigate the associations of physical loading from body weight using quantitative measures of disc degeneration.

Study design

This is an exposure-discordant twin study.

Methods

We selected 44 pairs of healthy male monozygotic (MZ) twins with 8 kg or more discordance in body weight (mean 13 kg), with lumbar magnetic resonance imaging and bone density measurements available. The main outcome of disc degeneration was assessed through quantitatively measured disc height, and disc signal intensity and signal variation adjusted by the intrabody reference, adjacent cerebrospinal fluid signal, at L1–L4. Data on suspected constitutional and environmental risk factors were available for control of possible confounding factors.

Results

Higher body weight was associated with 6.2% higher bone density in the lumbar spine, confirming an effective discordance (p<.0001). Disc signal variation was 5.4% higher (“better”) among the heavier MZ co-twins (p=.005), but the 2.6% higher disc heights and 2.9% higher adjusted disc signals were not statistically significant.

Conclusions

Contrary to common beliefs, our findings suggest that cumulative or repetitive loading because of higher body mass (nearly 30 pounds on average) was not harmful to the discs. In fact, a slight delay in L1–L4 disc desiccation was observed in the heavier men, as compared with their lighter twin brothers.

Adaptation, Body weight, Disc degeneration, Disc signal intensity, Physical loading, Twin-co-twin study

[JK2234]

Thank you for this info Justin...

Sadly I feel all my years of sports and heavy labor was great for my muscles but very bad for my spine...

I just turned 30 and feel my life is over already..

[Justin]

Thank you for this info Justin...

Sadly I feel all my years of sports and heavy labor was great for my muscles but very bad for my spine...

I just turned 30 and feel my life is over already..

Sure thing. Alison sent me the article to post (thanks Alison!).

I just turned 30 at the end of November and I have 3 spine surgeries under my belt. The best years are ahead of you! These are just little bumps in the road.