To investigate the cause of osteomalacia following biliopancreatic diversion (BPD) surgery for obesity.
A retrospective, case-comparison study.
A tertiary care center.
A case group of 12 subjects (including 9 women; mean age±SEM, 48.5±3.0 years; mean preoperative body mass index ±SEM, 43.7 ± 2.3 kg/m2; and mean weight loss±SEM, 75± 14 kg) who have undergone BPD (referred to as BPD group hereafter) and a comparison group of 10 subjects (including 9 women; mean age±SEM,49.6±3.3 years; mean preoperative body mass index ±SEM, 44.0 ± 2.5 kg/m2; and mean weight loss±SEM, 55±15 kg) following vertical banded gastroplasty (VBG) (referred to as VBG group hereafter).
Main Outcome Measures:
Serum and urine markers for bone metabolism.
Compared with the VBG group, the BPD group had significantly lower concentrations of the following components: serum calcium (2.14±0.05 mmol/L vs 2.37±0.05 mmol/L [8.6±0.2 mg/dL vs 9.5±0.2 mg/ dL]), serum 25-hydroxyvitamin D (24±6 nmol/L vs 64±6 nmol/L), urine calcium excretion (1.7±0.7 mmol/d vs 4.5±0.7 mmol/d [68±28 mg/d vs 180±28 mg/d]), and serum carotene (0.40±0.15 mmol/L vs 1.29±0.16 mmol/ L). The BPD group had significantly higher concentrations of the following components: serum parathyroid hormone (13.6±2.1 pmol/L vs 5.2±2.3 pmol/L), serum alkaline phosphatase (139±8 U/L vs 86 ± 9 U/L), and urinary hydroxyproline/creatinine (52±5 μmol/mmol vs 19±5 μmol/mmol).
These data suggest that following BPD, secondary hyperparathyroidism attributed to hypocalcemia results from malabsorption of vitamin D. However, we cannot exclude the possibility of concurrent calcium malabsorption with vitamin D malabsorption.Arch Surg. 1996;113:1048-1052