Vitamin D and bone mineral content after intestinal bypass operation for obesity.

Abstract

SUMMARY Twenty-three obese subjects who had undergone intestinal bypass operation (end-to-side jejunostomy) were studied with respect to vitamin D and other indices of calcium metabolism. Group 1 (11 patients) was examined before and one year after operation.

Obesity and bone metabolism

“…Early studies have shown that jejunoileal bypass (end-toside jejunoileostomy) for the management of morbid obesity increases the possibility of 25OHD deficiency, with vitamin D supplementation restoring it to normal levels [124], while others observed that vitamin D levels returned to postoperative levels without the need for supplementation, possibly due to much higher mobilization of fat stores [125].…”

Osteoporosis in Gastrointestinal, Pancreatic, and Hepatic Diseases

“…Restrictive procedures such as circumgastric banding or vertical banded gastroplasty seek to reduce the capacity of the stomach, leading to an obligatory restriction in oral intake of solids. Recovery occurs such that little or no osteopenia or osteoporosis can be appreciated by routine radiologic procedures [131][132][133][134]. These procedures are not expected to have much impact on bone mineral homeostasis, but this has not been well studied.…”

“…However, reductions in serum calcium and magnesium concentrations with an increase in serum alkaline phosphatase activity are observed in most subjects within 3 months of the operation and persist in approximately half the patients for years [131-134, 140, 141]. Serum 25OHD levels, which tend to be reduced in the obese patient prior to operation, fall even further in most individuals [131][132][133][134]141], although more recent studies in patients supplemented with vitamin D after their procedure have not shown this decrease. At least part of the fall in serum calcium can be attributed to the fall in albumin concentration.…”

“…1,25(OH)2D levels are often normal but may also be reduced [132,136,141]. In most studies osteomalacia is the dominant lesion found on bone biopsy [132][133][134][135], even when more restrictive criteria incorporating the results from double tetracycline labeling are used [136][137][138]. Reductions in bone density are generally not found, and fracture rates do not appear to be increased.…”

Morbidity and Mortality of Long-Term Haemodialysis: A Review

“…Osteomalacia usually predominates. Bone mineral content diminishes with increasing years of dialysis (Rickers et al 1983) but is slower if the calcium x phosphate product is normal.…”