Disc degeneration is a common problem as we get older. Adding a back injury or trauma to the mix could speed up that degenerative process. This injury model of disc degeneration is only one theory. There are also theories that say disc degeneration is the result of cumulative or repetitive loading of the spine. Disc loading can occur during work, sporting, or leisure activities.
To find out if a previous injury is a risk factor for later disc degeneration, researchers studied 37 pairs of twins (all men) who were part of an ongoing Twin Spine Study in Finland. They interviewed the men about past back problems and history of injuries on every job they had ever had. The same questions were asked regarding back injuries during any exercise, sporting, or leisure activity.
Conducting a twin study like this with identical twins of the same sex and age helps control for these factors that might otherwise influence the results. Various factors that might affect disc degeneration were considered. These variables included type of work (occupation) and load placed on the spine during labor, amount and type of exercise (sports or leisure), and any weight training the men had participated in over the years.
The main measure of disc health was MRI study. The height of the disc and disc signal intensity on MRI were used to assess current disc status. Everyone in the study had an MRI of the lumbar spine (L1 to S1) done.
They did not find any significant differences in disc height or signal between the twins who had a previous back injury and the twin who didn’t. This was true for all 37 pairs. Twin members who lifted more weight at work were more likely to injure their backs but this did not seem to translate into faster or greater disc degeneration later.
This is only one study but it does support the results of other studies looking into the injury model of disc degeneration. Long-term studies are really needed to see if time-delay is a factor.