Effect of Vitamin A Supplementation on Idiopathic Scoliosis

Idiopathic scoliosis (IS) is the most common structural spinal deformity in children and adolescents. Despite extensive research, its etiology remains largely unknown, resulting in a lack of modifiable targets for prevention or early intervention. Notably, preliminary unpublished data from our pediatric health center indicate a high prevalence (up to 30%) of mild scoliosis among children with vitamin A deficiency. Furthermore, our pilot data suggest a tendency toward vitamin A insufficiency in many children diagnosed with IS. Vitamin A is critical for normal bone growth, embryonic skeletal development, and the maintenance of epithelial tissues. We hypothesize that chronic vitamin A deficiency may represent a modifiable risk factor that contributes to the pathogenesis or progression of IS by disrupting these fundamental processes.

This study will be conducted at the "Child Health-Spine Wellness" Center. Children with idiopathic scoliosis and concurrent vitamin A deficiency or insufficiency will be randomized into one of two groups. The Intervention Group will receive sustained biochemical correction through daily oral vitamin A supplementation (2000 IU) for 6 months, coupled with a standardized nutritional education session. The Control Group will receive an identical nutritional education session but no study-provided supplements, serving as an active comparator that controls for the effects of increased health awareness and general dietary advice. For all children with scoliosis, routine follow-up visits with radiographic assessment will be scheduled at 6-month intervals for at least 24 months to evaluate curve progression. Additionally, children with vitamin A deficiency but without scoliosis at baseline will also be randomized to the same supplementation regimens and will undergo annual scoliosis screening as part of an ongoing provincial health initiative. All participants will undergo serial radiographic and clinical assessments.

At the same time, a structured safety monitoring plan will be implemented to prevent and promptly identify both vitamin A deficiency persistence and hypervitaminosis A. Prior to randomization, all caregivers will receive standardized education on the signs and symptoms of both significant vitamin A deficiency (e.g., night blindness, dry eyes) and acute/chronic hypervitaminosis A (e.g., headache, nausea/vomiting, dizziness, blurred vision, skin dryness/peeling). They will be instructed to report any such symptoms immediately to the study team via a dedicated 24-hour contact line. Serum retinol concentration will be measured for all participants at baseline and the 6-month visit. This serves the dual purpose of monitoring adherence in the Long-term. If a participant's serum retinol level exceeds 1.0 mg/L, the study supplementation will be immediately suspended, and the participant will be referred to a pediatric nutritionist for further evaluation and management.

Inclusion criteria

• Age between 6 and 15 years.
• Biochemically confirmed vitamin A deficiency (serum retinol < 0.20 mg/L) or insufficiency (serum retinol 0.20-0.29 mg/L).
• Has undergone radiographic evaluation (standing full-spine X-ray) for idiopathic scoliosis at the initial clinic visit.
• Skeletally immature (Risser sign 0-3) with a major Cobb angle < 40 degrees at baseline.
• Written informed consent/assent provided by the participant and legal guardian.

Exclusion criteria

• Unwillingness or inability to comply with all study procedures and follow-up visits.
• Plans to relocate outside the study area within the next 24 months.
• Previous high-dose vitamin A supplementation therapy within the past 12 months.
• Clinical signs of severe vitamin A deficiency syndrome (e.g., xerophthalmia, Bitot's spots).
• Serum vitamin A level > 0.70 mg/L (to avoid risk of hypervitaminosis A).
• Severe chronic health conditions that could confound study outcomes, including but not limited to:

• Known syndromic, neuromuscular, or congenital musculoskeletal causes of scoliosis.
• History of spine surgery or significant spinal trauma.
• Spinal tumor.
• Leg length discrepancy > 20 mm.
• Other severe chronic diseases (e.g., poorly controlled diabetes, chronic liver or renal disease, malabsorption syndromes).
• Severe obesity (body mass index z-score ≥ 3).