Adults develop scoliosis in two main ways: either a curve from adolescence progresses and becomes symptomatic later in life, or the spine develops a new curve due to age-related wear and tear. The second type, called degenerative or “de novo” scoliosis, forms in a previously straight spine and is by far the more common adult-onset form. An estimated 60% of adults over age 60 have some degree of scoliosis, making it one of the most widespread spinal conditions in older populations.
Degenerative Scoliosis: The Most Common Adult Type
Degenerative scoliosis develops when the discs and joints of the spine break down unevenly over time. Your spine stays upright through a balance of forces: the spongy discs between your vertebrae carry about 70% to 80% of your body’s weight, and the paired facet joints in the back of each vertebra handle the remaining 20% to 30%. When one disc loses height faster than its neighbor, or one facet joint wears out more than the one on the opposite side, the spine gradually tilts toward the weaker side.
This asymmetric breakdown is self-reinforcing. Once the spine shifts even slightly, the load distribution changes. The joints on the compressed side bear more weight, which accelerates cartilage loss on that side. Cartilage cells under abnormal pressure release inflammatory signals and enzymes that break down the surrounding tissue, thinning the cushion further. Over months and years, this creates a lateral curve that can progress at 3 degrees or more per year, significantly faster than the slow drift seen when a childhood curve worsens in adulthood.
Degenerative scoliosis almost always appears in the lower lumbar spine, typically between the ages of 40 and 70. It’s distinct from childhood scoliosis that carries into adulthood, which can involve the upper back and neck as well.
Childhood Curves That Progress in Adulthood
Some adults with scoliosis have had it since adolescence without knowing. Mild curves under 20 degrees often go undetected during school screenings and cause no symptoms for decades. As the spine ages, though, arthritis tends to develop more aggressively around an existing curve because the joints there have been under uneven stress for years. This can turn a painless, stable curve into one that causes stiffness, nerve compression, or worsening posture.
In a 20-year study tracking adult scoliosis patients, about 40% experienced some degree of curve progression. Of those, most saw mild worsening of less than one degree per year. About 10% showed significant progression. Whether a curve worsens depends on its size at the start (larger curves are less stable), the health of the surrounding discs and joints, and bone density.
Osteoporosis and Vertebral Fractures
Weakening bones are a direct pathway to adult-onset spinal curvature. When osteoporosis thins the vertebrae, they can fracture under ordinary stress, sometimes just from bending forward or lifting a bag of groceries. These compression fractures don’t always cause dramatic pain, but they change the shape of the vertebra. In the lower back, fractures typically collapse the middle of the vertebra unevenly, and the resulting shift in alignment puts extra downward pressure on the vertebra above. This sets off a chain reaction: after a first vertebral fracture, the risk of additional fractures increases fivefold.
In a review of patients with recurring lumbar fractures, all were female, had severe and often untreated osteoporosis, and all had developed scoliotic curves ranging from 6 to 50 degrees. The greater the curvature, the more frequently new fractures occurred, creating a cycle of worsening deformity and pain. Forty percent of these patients also had fractures in the sacrum, at the base of the spine.
Menopause is a major risk factor here. The drop in estrogen accelerates bone loss, and certain medications can compound the problem. Getting adequate calcium and vitamin D before and after menopause, and treating osteoporosis early, are among the most effective ways to prevent this type of scoliosis from developing.
Neurological Conditions
Diseases that affect how the brain controls muscles can pull the spine out of alignment. Parkinson’s disease is the best-studied example. Scoliosis is significantly more common in people with Parkinson’s than in the general elderly population, and the direction of the curve consistently matches the side of the body most affected by the disease. Researchers believe this happens because the loss of dopamine-producing cells in the brain creates an imbalance in the signals controlling trunk muscles on one side versus the other, essentially the same mechanism seen in animal studies where destroying dopamine pathways on one side of the brain produces a measurable spinal curve.
Stroke can produce a similar effect by weakening the trunk muscles on one side of the body. Any condition that creates a lasting asymmetry in muscle strength or tone, including certain forms of muscular dystrophy or spinal cord injury, can gradually pull the spine into a curve.
Previous Spinal Surgery
Back surgery itself can occasionally cause scoliosis. Laminectomy, a common procedure used to relieve pinched nerves from spinal stenosis, involves removing bone from the back of the vertebrae. When multiple levels are decompressed, the spine can lose structural support and develop a new curve. This is uncommon but more likely when the surgery spans several vertebral levels. The resulting instability can also appear within levels that were fused in a previous surgery, or at the segments just above or below a fusion, where the spine compensates for lost mobility by shifting position.
Risk Factors That Raise Your Chances
Several factors make degenerative scoliosis more likely, and most of them relate to the overall health of your bones and joints:
- Low bone density. Osteoporosis or osteopenia weakens vertebrae and makes asymmetric collapse more likely.
- Female sex. Women face higher rates of both osteoporosis and degenerative scoliosis, particularly after menopause.
- Pre-existing spinal arthritis. Joints already damaged by wear-and-tear arthritis are more prone to uneven breakdown.
- Family history. Genetics play a role in both adolescent scoliosis and susceptibility to disc degeneration, though the exact genes involved are still being defined.
- Prior spinal injury or surgery. Any event that changes spinal mechanics on one side can set the stage for a curve.
How Adult Scoliosis Is Identified
A spinal curve is formally classified as scoliosis when it measures 10 degrees or more on an X-ray, using a calculation called the Cobb angle. Below 10 degrees, it’s considered a normal variant. Curves between 10 and 20 degrees are classified as mild. For degenerative scoliosis specifically, the Cobb angle alone doesn’t capture the full picture the way it does for adolescent curves, because the pain and disability often come more from nerve compression and joint inflammation than from the degree of curvature itself.
Many adults discover scoliosis incidentally, during imaging for back pain or another condition. The curve itself may not be the primary source of symptoms. Leg pain from pinched nerves, difficulty standing upright, or a feeling of being off-balance are often what bring people in for evaluation, and the scoliosis turns out to be the underlying structural reason.