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The impact of bariatric surgery on the bone health of paediatric and adolescents

Bariatric surgery is highly effective at achieving weight loss in paediatric patients however sleeve gastrectomy (SG) and Roux-en-Y-gastric bypass (RYGB) are associated with poorer markers of bone health, therefore it is important to recognise the vulnerabilities of in this group in developing micronutrient deficiencies translating to medium and long-term health risks after surgery, according to a systematic review and meta-analysis study led by researchers from Imperial College London, London, UK.


The investigators conducted a systematic search on all studies reporting calcium and/or bone mineral density (BMD) in paediatric patients (<18 years) undergoing any bariatric intervention up to September. They identified 12 studies (nine prospective cohort studies, two retrospective case reviews and one RCT) from five countries with a total of 681 patients (61% female) with a mean age of 17±0.57 years with an average follow up was 16 months (range 8–26 months). Patients underwent either RYGB (n=216), sleeve gastrectomy (n=257), gastric band (n=184) or intragastric balloon (n=24). The average follow up was 16 months (range 8–26 months).


All studies reported significant reduction in absolute weight of 33.7kg at the study end point (p<0.0010) and BMI of −12.67kg/m2 following surgery (p<0.0010). Weight loss was greater with SG and RYGB compared to IAGB and LAGB. A subgroup analysis of RYGB and SG, RYGB generated greater weight loss over SG, weighted mean BMI reduction of 16.6kg/m2 (p<0.001) versus SG (12.9kg/m2 (p<0.0010).


Regarding bone biochemistry, four studies with a total of 744 patients who underwent SG or RYGB evaluated total calcium levels before and after surgery. Pooled results demonstrated lower calcium following surgery, standardized mean reduction of −3.8mg/dl (p=0.001). Of those patients, the majority (n=510) underwent SG and the results did not demonstrate any difference in calcium levels before or after surgery (p=0.52).


In addition, the study also found:

  • Three studies with a total of 264 patients reported alkaline phosphatase (ALP) before and after RYGB. Reporting there was no change in ALP following surgery (p=0.23).

  • Eleven studies with a total of 553 patients evaluated 25OHD levels pre- and post-BS. For all studies combined, there was no difference in 25OHD, 0.41ng/ml (p=0.77). Subgroup analysis by studies only performing SG (n=452) or RYGB (n=264) reported no difference in 25OHD levels between the groups following surgery, −0.25 ng/ml (p=0.62).

  • Four studies with a total of 262 patients who underwent SG or RYGB evaluated P1NP levels, demonstrating no difference following surgery (p=0.37).

  • There was significantly lower BMD following pooled surgical procedures, weighted mean reduction of −0.04 g/cm2 (p=0.04).

  • There was a significant reduction in BMD in patients who underwent SG or RYGB only.


“This is the first systematic review and meta-analysis to evaluate the effects of BS in the paediatric population on bone outcomes. The principal findings are, BS is highly effective at achieving significant weight loss however, SG and RYGB are associated with poorer markers of bone health in the medium-term,” the authors write. “In addition, untreated micronutrient deficiencies in childhood are associated with other systemic illnesses such as autoimmune disorders, cognitive impairment and increased susceptibility to infections. Acknowledging these risks post paediatric BS and treating them promptly is fundamental given the increase in global childhood obesity and the rising application of BS as a solution to this problem.”


This study was funded by the UK’s Medical Research Council.


The findings were reported in the paper, ‘Bone health following paediatric and adolescent bariatric surgery: a systematic review and meta-analysis’, published in eClinicalMedicine. To access this paper, please click here

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