Determinants of High Parathyroid Hormone Levels in Patients With Severe Obesity and Their Relationship With the Cardiometabolic Risk Factors, Before and After a Laparoscopic Sleeve Gastrectomy Intervention.

BACKGROUND: Obesity is a risk factor for vitamin D deficiency and hyperparathyroidism. Hyperparathyroidism could exert a negative effect on glucose metabolism and vascular function. The aim of this study was to identify the determinants of hyperparathyroidism beyond vitamin D deficiency, whether hyperparathyroidism could have a negative impact on individual health and whether laparoscopic sleeve gastrectomy (LSG) negatively affects the levels of intact parathyroid hormone (iPTH) and 25(OH) vitamin D (25(OH)D). METHODS: We evaluated the levels of iPTH, 25(OH)D, and leptin, together with markers of insulin sensitivity and early cardiovascular disease, in a cohort of 160 patients with severe obesity before and after an LSG intervention. RESULTS: Ninety-seven percent of subjects had vitamin D deficiency, and 72% of them had hyperparathyroidism. After correcting for possible confounders, we found a correlation between iPTH levels and carotid intima-media thickness, as well as with the HOMA index. After the LSG, 25(OH)D levels were significantly increased, while iPTH levels were significantly reduced. The reduction of iPTH was significantly correlated with the reduction of BMI, diastolic blood pressure, and leptin, which was the independent predictor of iPTH reduction. CONCLUSIONS: Our results suggest that vitamin D deficiency is not the sole determinant of hyperparathyroidism in severe obesity because visceral fat deposition and leptin could both play a role. Obesity-related hyperparathyroidism is associated with insulin resistance and atherosclerosis, although the results from previous studies were conflicting. Finally, LSG intervention does not negatively affect vitamin D status and improves hyperparathyroidism.

Laparoscopic sleeve gastrectomy modifies cholesterol synthesis but not cholesterol absorption.

BACKGROUND AND AIMS: Each bariatric surgery procedure impacts differently on cholesterol synthesis and absorption. Although a restrictive procedure, sleeve gastrectomy resolves diabetes mellitus and, like mixed-type procedures, induces early changes in gastrointestinal hormones. To our knowledge the present study is the first to assess the effects of sleeve gastrectomy on cholesterol synthesis and absorption. METHODS AND RESULTS: 42 consecutive subjects with obesity and sleeve gastrectomy candidates were included in the study together with a control group of 20 subjects without obesity. Before sleeve gastrectomy and 10 months afterwards, all subjects underwent a clinical examination, blood tests, ultrasound visceral fat area estimation and determination of plasma lathosterol, campesterol and sitosterol concentrations. After sleeve gastrectomy, significant decreases were observed in BMI, waist circumference, visceral and subcutaneous fat, blood pressure, triglycerides, insulin and glucose levels, lathosterol and HOMA-IR. HDL-C and apolipoprotein AI levels increased significantly. No significant differences emerged in LDL-C, apolipoprotein B levels or cholesterol absorption markers. Lathosterol levels correlated significantly with BMI, visceral fat area and HOMA-IR. Differences in cholesterol intake after surgery were not significantly associated with differences in lathosterol, campesterol and sitosterol concentrations. CONCLUSIONS: Sleeve gastrectomy reduced the markers of cholesterol synthesis but did not modify cholesterol absorption. Changes in cholesterol synthesis and absorption were independent of variations in cholesterol intake, suggesting a specific sleeve gastrectomy-related effect.