Osteoarthritis of the back is extremely common. A major Japanese study published in the journal "Bone Mineral Metabolism" in 2009 found this condition to be present in 45 percent of male study participants aged 40 to 49, and in 90 percent by age 80. The figures for women were just a bit lower. A separate study published in the "British Journal of Radiology" in 2007 found references to degenerative changes in the spine in 74 percent of X-ray reports across all ages. Though this type of arthritis is often attributed to aging and wear-and-tear, specific contributing causes have been identified.
Trauma
Injuries, whether they are to the discs, ligaments, supporting muscles or to the bone itself, have the potential of altering the normal movement patterns of spinal joints. Ultimately, these altered movement patterns tend to cause changes in the spinal discs and joint cartilages that we associate with osteoarthritis. These injuries may not be initially apparent on medical imaging such as X-ray, but altered or inefficient movement patterns may, over time cause unbalanced loading on the weight-bearing surfaces of the joints.
Genetics
Unfortunately, one of the greatest contributing factors in the development of spinal osteoarthritis may be one that is beyond control--your heredity. Research based heavily on studies of twins has estimated that the overall contribution of genetics is 50 percent or greater for this condition. This research, published in the journal "Osteoarthritis and Cartilage" in 2004 describes several chromosomal traits that have been linked to osteoarthritis. The genetic link appears to be particularly strong for spinal osteoarthritis.
Occupation
Aside from exposure to trauma in the workplace, there are certain characteristics of work activities that have been found to be associated with the increased likelihood of developing spinal osteoarthritis. Daily spine loading such as twisting, lifting, bending and sustained non-neutral postures, and whole body vibration such as vehicular driving are factors which increase both the likelihood and severity of spinal arthritis. Construction workers, nurses' aids and truck drivers would likely be exposed to conditions that often lead to the development of osteoarthritis in the spine.
Posture
Much of what we know about the effects of body postures on spinal loading originate from the pioneering work of Dr. Alf Nachemson who, back in the 1960s developed a method to measure actual load pressures within the discs of the lower spine. Pressures were found to increase significantly as subjects progressed from lying to standing to sitting. Bending forward while sitting in a chair was found to result in loading that is several times greater than pressures measured while recumbent. Excessive loading of the spinal discs contributes to increased incidence of disc injury and cumulative wear and tear.
References
- "Journal of Bone Mineral Metabolism;" Prevalence of Knee Osteoarthritis, Lumbar Spondylosis, and Osteoporosis in Japanese Men and Women: The Research on Osteoarthritis/Osteoporosis Against Disability Study; N Yoshimura, S Muraki, H Oka, et al; 2009
- "British Journal of Radiology;" Content Analysis of General Practitioner-Requested Lumbar Spine X-ray Reports; P Thompson and E Carr; November 2007
- "Osteoarthritis and Cartilage;" Risk Factors for Osteoarthritis: Genetics; T Spector and A MacGregor; 2004
