EBQ:Twin Spine Study
What is the contribution of genetics to disc degeneration?
There is a substantial influence of heredity on lumbar disc degeneration. There is little effect on disc degeneration from occupational and leisure-time physical loading, and increased loading may have a small benefit. There is only a small effect from smoking. Body weight and muscle strength have modest effects on disc degeneration. Some candidate genes were identified.
The Twin Spine Study, which started in 1991, is a multidisciplinary, multinational research project with collaborators primarily in Canada, Finland, and the United States. They investigated occupational exposures, driving and whole-body vibration exposure, smoking exposure, anthropomorphic factors, heritability, and the identification of genotypes associated with disc degeneration.
- T12–L4 region: 61% of the variance in disc degeneration was explained by familial aggregation, beyond that of age and occupational physical loading that together explained 16%.
- L4–S1 discs: 11% of disc degeneration was explained by physical loading and age, which rose to 43% once familial aggregation was added to the model. In contrast to the upper lumbar levels, 57% remained unexplained in the lower lumbar region