Researchers hypothesized that Bifidobacterium breve Supplement could reduce the progression rate of idiopathic scoliosis in children and potentially prevent the occurrence of new cases of scoliosis.

Idiopathic scoliosis (IS) is a common pediatric disorder characterized by a spinal curvature exceeding 10 degrees that develops in the absence of obvious congenital or physiological defects. IS is highly prevalent during adolescence, afflicting 3-4% of children worldwide, yet the underlying causes remain poorly understood. Recent studies have indicated that children with idiopathic scoliosis have a disrupted gut microbiota, but there is currently no clinical data on the impact of any probiotic supplementation on scoliosis. Our unpublished data show that the abundance of probiotics such as Bifidobacterium breve in the intestines of children with idiopathic scoliosis is reduced, while the levels of multiple bile acids in the blood are elevated. Therefore, we hypothesize that Bifidobacterium breve supplementation can reduce the progression rate of idiopathic scoliosis in children and may have a potential role in preventing the onset of new cases of scoliosis in children.

This study is a single-blind, randomized controlled trial to investigate the effect of Bifidobacterium breve on the magnitude of idiopathic spinal curves. Eligible scoliosis children will be randomly assigned to one of two groups. The intervention group will receive oral supplementation of Bifidobacterium breve at 4.5x106 CFU daily for 6 months, along with a standardized gut microbiota-related health course for lifestyle correction (such as adjusting diet, moderate exercise, and reducing antibiotic abuse). The intervention group will be subject to regular phone follow-ups to inquire about probiotic intake and be encouraged to adhere to the regimen. The control group will receive the same health course but no probiotic supplementation, serving as an active control to account for the impact of lifestyle improvements. For all scoliosis children, routine follow-up visits will be scheduled every 6 months for at least 24 months to assess curve progression. Additionally, children who have not yet reached the scoliosis threshold at baseline will also be invited and randomly assigned to the same grouping scheme or simply followed up as observational subjects. All participating children, as part of a provincial health program in Zhejiang Province, will undergo annual scoliosis screening and clinical assessment.

Inclusion Criteria:

• Age 6 to 15 years

Diagnosed with idiopathic scoliosis based on clinical evaluation and radiographic examination at the first clinic visit

Skeletally immature, defined as Risser sign 0 to 3

Major Cobb angle < 40 degrees at baseline

Written informed consent provided by the participant or legal guardian

Able and willing to comply with study procedures

Exclusion Criteria:

• Plans to relocate within the next 24 months

Use of antibiotics, probiotics, hormones, immunosuppressants, or other nutritional supplements known to affect gut microbiota within the past 3 months or during the study period without investigator approval

Known allergy, sensitivity, or intolerance to the investigational product or its ingredients

Current or prior significant gastrointestinal disease requiring medication, or history of gastrointestinal surgery

Severe gastrointestinal symptoms such as persistent heartburn or indigestion

Musculoskeletal, neurodevelopmental, syndromic, or other conditions that may account for the spinal deformity

History of spine surgery or major spinal injury

Spinal tumor or malignant disease involving the spine

Leg length discrepancy > 20 mm

Severe chronic diseases that could interfere with study participation or outcome assessment, including but not limited to diabetes, narcolepsy, or poorly controlled asthma

Severe obesity, defined as BMI z-score ≥ 3