Bone health following paediatric and adolescent bariatric surgery: a systematic review and meta-analysis

Abstract

Background: Childhood obesity is a pressing health crisis of epidemic proportions. Bariatric surgery (BS) is an effective weight loss solution however its role in the paediatric population is contentious owing to the paucity of weight specific and generalised health outcomes. This systematic review and meta-analysis aimed to assess the impact of paediatric BS on bone health.

Methods: This prospectively registered systematic review (PROSPERO ID: CRD42023432035) was performed in accordance with PRISMA guidelines. We searched MEDLINE (1946-1928 September 2023), EMBASE (1947-1928 September 2023) via the Ovid platform, and the Cochrane Review Library to identify scientific publications reporting bone outcome measures in patients under the age of 18 years who underwent BS. Meta-analysis was undertaken on post-operative weight and bone parameters in paediatric patients following BS. Outcomes were reported as weighted or standardized mean difference with 95 percent confidence intervals. Subgroup analysis by intervention, quality scoring and risk of bias were assessed.

Findings: Twelve studies with 681 patients across 5 countries (mean age 17 ± 0.57 years) were included. The quality of included studies was rated as high and there was substantial between-study heterogeneity for most factors included in the meta-analysis (I² from 0% to 99.1%). Patients underwent Roux-en-Y gastric bypass (RYGB, n = 216), sleeve gastrectomy (SG, n = 257), gastric band (n = 184) or intragastric balloon placement (n = 24). BS was associated with significant weight reduction, body mass index (BMI) -12.7 kg/m² (95% CI -14.5 to -10.9, p < 0.001), with RYGB being most effective, BMI -16.58 kg/m² (95% CI -19.6 to -13.6, p < 0.001). Patients who underwent SG or RYGB had significantly lower lumbar bone mineral density, -0.96 g/cm² (95% CI -0.1 to -0.03, p < 0.001), Z score, -1.132 (95% CI -1.8 to -0.45, p < 0.001) and subtotal body bone mineral density, -0.7 g/cm² (95% CI -1.2 to -0.2, p < 0.001) following surgery. This was accompanied with higher markers of bone resorption, C-terminal telopeptide of type 1 collagen 0.22 ng/ml (95% CI 0.12-0.32, p < 0.001) and osteocalcin, 10.83 ng/ml (95% CI 6.01-15.67, p < 0.001). There was a significant reduction in calcium levels following BS, -3.78 mg/dl (95% CI -6.1 to -1.5, p < 0.001) but no difference in 25-hydroxyvitamin D, phosphate, bone alkaline phosphatase, procollagen type 1 N propeptide or parathyroid hormone.

Interpretation: BS effectively reduces weight in paediatric patients, but RYGB and SG may have adverse effects on bone health in the medium term. It is crucial to monitor and support bone health through appropriate nutritional supplementation and judicious follow-up. Long-term data is needed to fully understand the clinical implications of these findings on bone outcomes.

Funding: Medical Research Council (MRC), United Kingdom.

Keywords: Adolescent; BMD; Bariatric; Bone; Calcium; Paediatric.

Fig. 1

PRISMA flow chart of search results and studyselection.

Fig. 2

Weight loss outcomes following paediatric bariatric surgery. Random effects modelling of meta-analysis data on weight outcomes in paediatric patients before and after bariatric surgery (BS). A) Absolute weight (kg) and B) Body mass index following all BS procedures. C) Weighted mean reduction (kg) following malabsorptive versus D) restrictive BS interventions. E) Weighted mean difference following Roux-en-Y gastric bypass and F) sleeve gastrectomy.

Fig. 3

Bone biochemistry outcomes following Paediatric Bariatric Surgery. Random effects modelling of meta-analysis data on biochemical bone parameters before and after bariatric surgery (BS). A) Calcium levels from pooled BS interventions and B) from sleeve gastrectomy (SG) only, C) bone alkaline phosphatase and D) 25-hydroxyvitamin D levels from combined BS procedures and from, E) SG and Roux-en-Y gastric bypass only, F) procollagen type 1 N propeptide levels, G) phosphate and H) parathyroid levels following BS.

Fig. 4

Bone resorptive markers following Paediatric Bariatric Surgery. Random effects modelling of meta-analysis data on markers of bone resorption before and after bariatric surgery (BS). Weighted mean difference in A) C-terminal telopeptide and B) Osteocalcin following bariatric surgery.

Fig. 5

Radiological markers of Bone Health following Paediatric Bariatric Surgery. Random effects modelling of meta-analysis data on radiological evaluation of bone health in paediatric patients before and after bariatric surgery (BS). A) Lumbar bone mineral density (BMD) from all procedures combined, B) BMD from malabsorptive BS and C) restrictive BS interventions, D) Z score from pooled BS, E) Z score from malabsorptive BS, F) restrictive BS interventions and G) subtotal bone mineral density.