Understanding Scoliosis Progression: Risk Factors Across the Lifespan -

Written by Exeval Almabra (Physiotherapist and Scoliosis Specialist)

Scoliosis is a condition where the spine gradually curves to the side, often taking on a gentle “S” or “C” shape. For many people, this curve remains small and stable. But in some cases—particularly during growth or later in life—changes in the spine can cause the curve to increase.

Let’s explore:

- When and why scoliosis might progress

- Key risk factors across childhood, adolescence, and adulthood

- The role of growth, bone health (including vitamin D), bracing, and exercise- Insights for clinicians, with gentle guidance for patients

Scoliosis in Growing Children and Teens

Juvenile Idiopathic Scoliosis (JIS): Ages 4–10

JIS is diagnosed in children between the ages of 4 and 10. It makes up about 10–15% of idiopathic scoliosis cases. Because children in this age group are still years away from their major growth spurt, monitoring is essential.

Risk factors for curve progression in JIS include:

- Larger curve size at diagnosis: The spine is more likely to keep shifting if the curve is already noticeable.

- Growth potential: Children with more years of growth ahead may experience more changes.

- Family history: Scoliosis in a parent or sibling increases the chance of curve changes.

- Curve pattern and rate of change: Some curve shapes—especially those in the mid-back—are more prone to gradual progression.

- Clinical insight: In children whose curve exceeds a certain threshold early on, up to 9 out of 10 may eventually need formal intervention to help manage spinal development (Coillard et al., 2010).

Adolescent Idiopathic Scoliosis (AIS): Ages 10+

AIS is the most common form of scoliosis and typically appears during the early teen years, often around the time of a growth spurt.

Key factors that influence AIS progression:

- Curve size at first assessment: Curves measuring between 10°–20° often remain stable, while those starting at 21°–30° have a noticeably higher chance of progression—particularly in younger adolescents.

- Skeletal maturity: Teens who are early in their growth phase are more likely to see curve progression.

- Curve location and pattern:

  - In girls, right upper-back curves and S-shaped patterns are more likely to change.

  - In boys, lower-back right curves tend to have a higher chance of progression.

• Growth markers (e.g., Risser sign):

  • At Risser 0–1: Curves under 20° show ~1 in 5 risk of increasing, while 21–30° curves progress in roughly 2 out of 3 cases.

  • At Risser 2–4: Progression risk drops significantly, with 21–30° curves increasing in about 1 in 4 cases.

- Muscle and bone support: EMG studies suggest lower activation and fatty infiltration on the concave side of the curve, which may reduce local muscle endurance and contribute to progression during rapid growth phases.

Vitamin D and Adolescent Idiopathic Scoliosis

Vitamin D is essential for healthy bones—especially during growth. Low vitamin D levels may reduce bone strength and influence how the spine handles everyday loading forces.

- A 2023 meta-analysis found that teens with scoliosis often had slightly lower vitamin D levels than their peers, although the difference wasn’t statistically strong (Kim & Lee, 2023).

- Maintaining healthy vitamin D through diet, sunlight, or supplementation can support spinal and bone health during key growth years.

- Clinically, keeping vitamin D in the optimal range can be a proactive part of overall scoliosis care.

How Bracing and Exercise Help Slow Scoliosis Progression

Scoliosis doesn’t usually worsen randomly — it tends to follow a predictable, self-reinforcing cycle during growth. This cycle involves both mechanical forces and growth-related changes in the spine.

The feedback loop of scoliosis progression:

1. Uneven pressure on the growth plates: As a spinal curve begins, one side of the vertebral growth plate is compressed while the other is stretched.

2. Asymmetrical growth (Hueter-Volkmann principle): Compression slows growth on one side, while tension accelerates it on the other — leading to further imbalance.

3. Vertebral wedging: Over time, this uneven growth causes the vertebrae to become wedge-shaped, reinforcing the curve’s structure.

4. Increasing mechanical asymmetry: As the curve increases, it places even more uneven forces on the spine — and the cycle repeats.

How bracing disrupts the cycle:

Bracing is designed to interrupt this feedback loop by redistributing forces across the spine, guiding it to grow in a more balanced way. It doesn’t aim to “fix” the curve instantly, but to reduce the chance of progression during growth spurts.

- Targeted pressure zones in the brace encourage muscle activation and improved posture.

- Spinal flexibility is a strong predictor of brace success — the more the spine can correct in a lying position, the more influence the brace can have.

- Consistent wear (typically 16–23 hours/day) improves outcomes significantly.

- Brace design matters: Rigo-Chêneau, Boston, or dynamic braces are tailored to each person’s curve pattern and flexibility profile.

Why exercise strengthens the effect:

Exercise programs like Schroth therapy complement bracing by retraining posture, building strength on the underactive (concave) side of the spine, and promoting muscular symmetry. When performed consistently, these exercises improve body awareness, enhance breathing mechanics, and reduce muscular compensation patterns.

Together, bracing and exercise don’t just respond to the curve — they proactively shape how the spine grows, helping to preserve long-term balance, function, and confidence.

Growth Milestones and Monitoring Windows

Knowing when a child or teen is likely to grow helps us predict when to watch most closely. Here's a general guide:

Milestone	Girls	Boys
Growth spurt typically begins	~11 years	~13 years
Growth begins to slow	~13 years	~15 years
Skeletal maturity largely complete	~18 years	~18 years

Adult and Post-Growth Scoliosis

Even after growth ends, scoliosis can continue to shift over time—especially when combined with natural aging, posture changes, and disc or joint wear. Adults typically fall into two groups:1. Those with scoliosis from adolescence (skeletally mature scoliosis)2. Those who develop scoliosis later in life (de novo scoliosis)

Skeletally Mature Idiopathic Scoliosis

These individuals were diagnosed in their teens but have now completed growth. While progression is usually slower, it can still happen, particularly for those with moderate-to-large curves.

What contributes to changes:

- Curve size at maturity: Those whose curve exceeded ~30–40° at the end of growth are more likely to see gradual changes in adulthood.

- Muscle imbalance: Fatigue or weakness in spinal stabilisers can allow subtle shifts.

- Sagittal balance: Changes in the spine’s side profile (e.g., loss of lumbar lordosis) may lead to compensatory curving.

- Spinal loading: Daily activities—like sitting, lifting, or working in asymmetrical postures—can influence curve behavior over decades.

For clinicians: Slow progression rates (~1°/year) are most common in curves above 50°, especially if muscle support is reduced or sagittal imbalance is present.

Management includes:

- Regular posture and strength-based exercise

- Ergonomic education

- Periodic imaging if symptoms or visible changes occur

- Bone health monitoring (especially post-menopause)

De Novo Scoliosis: Scoliosis That Begins in Adulthood

This type of scoliosis develops later in life, often after age 40 or 50, in individuals who had no prior curve in adolescence. It is usually due to natural aging of the spine.

Why it develops:

- Disc and joint wear: Uneven pressure leads to tilting and rotation of spinal segments.

- Muscle deconditioning: Weakness in the core and spine can lead to gradual loss of alignment.

- Bone health: Lower bone density or subtle wedge fractures can introduce spinal tilt.

Signs to watch for:

- A slow, visible shift in posture

- Discomfort or tightness on one side

- Reduced walking tolerance or spinal stiffness

Management strategies:

- Conservative strengthening and flexibility work

- Core-focused rehab and gait training

- Weight-bearing exercise for bone support

- Medical assessment when necessary for bone or disc-related changes

Muscle Patterns and Biomechanics

EMG studies have shown that muscles on the inner (concave) side of the curve often display weakness and may have fatty infiltration. Over time, this contributes to uneven muscular support of the spine.

The sagittal profile of the spine also plays a role:

- Excessive kyphosis in the upper back or increased lordosis in the lower back creates more space for spinal rotation.

- This rotational capacity can increase 3D spinal shifting and influence progression, particularly in flexible spines or those with asymmetric loading patterns.

Final Thoughts

Scoliosis is not always predictable, but it is manageable. Whether in a growing child or a mature adult, knowing what to watch for—and when—is key to maintaining a healthy spine.

Early detection, consistent monitoring, and a collaborative approach between patients, families, and clinicians can help preserve both posture and confidence at every stage of life.

References (APA 7th Edition)

Coillard, C., Circo, A. B., & Rivard, C. H. (2010). SpineCor treatment for juvenile idiopathic scoliosis: SOSORT award 2010 winner. Scoliosis, 5(1), 25. https://doi.org/10.1186/1748-7161-5-25

Charles, Y. P., Daures, J. P., de Rosa, V., & Dimeglio, A. (2006). Progression risk of idiopathic juvenile scoliosis during pubertal growth. Spine, 31(17), 1933–1942. https://doi.org/10.1097/01.brs.0000229230.68870.97

Sanders, J. O., et al. (2008). Predicting scoliosis progression from skeletal maturity: A simplified classification during adolescence. Journal of Bone and Joint Surgery. American Volume, 90(3), 540–553. https://doi.org/10.2106/JBJS.G.00004

Kim, D. S., & Lee, J. S. (2023). Vitamin D in adolescent idiopathic scoliosis: A meta-analysis. BMC Musculoskeletal Disorders, 24(1), 689. https://doi.org/10.1186/s12891-023-06793-0