Traditional thinking has been that degenerative discs were primarily the result of handling heavy materials, postural loading, and vehicular vibration. There is now evidence that challenges that traditional thinking.

Michele Crites-Battié, faculty of Rehabilitation Medicine, University of Alberta, studied 147 pairs of identical twins, and 153 pairs of fraternal male twins, to determine what role occupational workloads contributed to degenerative discs. In one example, one of the twins had a sedentary job, while the other’s occupation required heavy physical demands. In another example, one twin routinely engaged in occupational driving, while the other did not. The study’s results were startling.

The study suggest that genetics plays a more significant role in disc degeneration than previously thought. While physical loading–handling heavy loads, bending, twisting, and static work in awkward postures–appears to influence disc degeneration, the effects are very modest. Comparing images of twins side-by-side showed a remarkable similarity in degree of degeneration and the spinal levels involved.

This new understanding of disc degeneration provides a foundation from which to develop a new hypotheses and may help shed light on one of the most common and costly musculoskeletal conditions facing the developed countries of the world.

Researchers are now working to identify the specific genes and biological mechanisms influencing disc degeneration and back pain problems.