Reduced bone mineral density after surgical treatment for obesity

Abstract

OBJECTIVE: To investigate whether osteoporosis occurs after surgical treatment for obesity. DESIGN: A cross-sectional study of ®ve groups of subjects who had undergone surgical treatment for obesity: ®ve premenopausal women; 13 post-menopausal women; seven post-menopausal women taking oestrogen replacement (HRT); ®ve men; and six women who had undergone surgical reversal (mean time 7 y). SUBJECTS: Thirty-six Caucasian subjects who had undergone jejunoileal or pancreaticobiliary bypass surgery at St George's Hospital between 1971 and 1992. Their mean age was 50.8 y (range 32 ± 69 y) and the median time since the operation was 14.8 y (range 4 ± 23 y). MEASUREMENTS: A clinical questionnaire was used to exclude possible factors, which might in¯uence bone mineral density. A single blood sample was collected for measurement of calcium, phosphate, alkaline phosphatase, albumin, magnesium, zinc, creatinine, thyroxine, 25-hydroxy-vitamin D, sex steroids, gonadotrophins and IGF-1 and 24 h urine calcium excretion was measured. Bone mineral density (BMD) was measured in the lumbar (L2-L4) spine (LS) and femoral neck (FN) by dual energy X-ray absorptiometry (DEXA). RESULTS: There was no difference in serum calcium, alkaline phosphatase, IGF-1, 25-hydroxy-vitamin D (25-OH vitamin D), magnesium or zinc concentrations between the ®ve groups. The LS-BMD T score was lower (P`0.05) in male subjects ( 7 2.08 AE 1.04 mean 1.0 AE s.d) and post-menopausal women not taking HRT ( 7 1.21 AE 1.33) compared to the surgically reversed group (0.87 AE 2.36). The male group was most severely affected, despite normal serum testosterone concentrations. Two of the ®ve men studied, had a LS-BMD T score`7 2.5 and two had a LS-BMD T score between 7 1.0 and 7 2.5. In contrast, six of the seven post-menopausal women on HRT had an LS BMD T score b 7 1.0. There was no difference in the FN-BMD between the ®ve groups. The presence of low BMD was not related to age, duration of bypass, or degree of postoperative weight loss. Iliac crest bone biopsies in three subjects with low BMD, con®rmed the presence of osteoporosis. CONCLUSIONS: Reduced bone mineral density is a complication of jejunoileal bypass surgery.

Risk of secondary hyperparathyroidism after laparoscopic gastric bypass surgery in obese women

“…However, there is solid evidence that obesity is usually protective against osteoporosis, and even moderate weight loss has been reported to reduce bone mineral density (BMD) [23]. With more dramatic weight loss there is an increased risk of low bone mass and metabolic bone disease [1,4,6]. Coates et al described the development of marked bone resorption and loss of bone mass in patients who undergo gastric bypass for morbid obesity [4].…”

Effect of Roux-en Y Gastric Bypass on Bone Metabolism in Patients with Morbid Obesity: Mansoura Experiences

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Calcium Intake and Metabolic Bone Disease after Eight Years of Roux-en-Y Gastric Bypass

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