What do you learn by looking at the spines of hundreds of Finnish twins?
If you are the international team of researchers behind the Twin Spine Study, you find compelling proof that back pain problems may be more a matter of genetics than physical strain.
The findings of the Twin Spine Study, an ongoing research program started in 1991, have led to a dramatic paradigm shift in the way disc degeneration is understood. Last month a paper presenting an overview of the Twin Spine Study's multidisciplinary investigation into the root causes of disc degeneration received a Kappa Delta Award from the American Academy of Orthopaedic Surgeons, arguably the most prestigious annual award in musculoskeletal research.
“In the past, the factors most commonly suspected of accelerating degenerative changes in the discs were various occupational physical loading conditions, such as handling of heavy materials, postural loading and vehicular vibration,” said lead researcher Michele Crites-Battié of the University of Alberta's Faculty of Rehabilitation Medicine.
Drawing on information from 600 participants in the population-based Finnish Twin Cohort—147 pairs of identical and 153 pairs of fraternal male twins—the Twin Spine Study has turned the dominant “injury model” approach to disc degeneration on its head. Researchers from Canada, Finland, the United States and the United Kingdom compared identical twin siblings who differed greatly in their exposure to a suspected risk factor for back problems; for example, one of the twins had a sedentary job while the other had heavy occupational physical demands, or one routinely engaged in occupational driving while the other did not. The studies yielded startling results, suggesting that genetics play a much larger role in disc degeneration than previously thought.