Vitamin D Concentration Changes after Bariatric Surgery.

Introduction: Bariatric surgery causes physiological and anatomical changes in the gastrointestinal tract that interfere with intestinal absorption and, consequently, with the nutritional status, especially about vitamin D. The aim of the study was to evaluate the vitamin D levels and body composition of these patients in the Roux-en-Y gastric bypass (RYGB) and vertical sleeve gastrectomy (VSG) types of surgery. Methods: The retrospective cohort study included a population of 120 patients aged between 18 and 65 years, with class II or III obesity, undergoing bariatric surgery procedures (VSG or RYGB-type). Data were collected on the degree of obesity, age, average time since surgery, and gender. The individuals underwent a complete physical examination, measuring blood pressure, weight, height, waist, and neck circumference. In addition to calculating the percentage of loss of body weight and assessing body fat, the food frequency and physical activity of these patients were evaluated. Blood was collected, and the insulin variables, hydroxyvitamin D (25OHD), were analyzed. Results: There was a significant difference between groups only for PTH, total BMD, and insulin variables. A significant intragroup difference was found in the variables' body mass index (BMI) and vitamin D for the vertical sleeve gastrectomy group and BMI for the RYGB group. Conclusion: The analysis between the groups of procedures, similarity in body composition and postsurgical vitamin D levels, with significant differences only for PTH, BMD, and insulin variables, demonstrates that both procedures are effective in reducing fat mass.

Fracture Risk After Bariatric Surgery: A Systematic Literature Review and Meta-Analysis.

OBJECTIVE: Bariatric surgery has undeniable benefits for cardiovascular and metabolic health, but it can result in negative effects on mineral and bone metabolism. This study aimed to review the current data on fractures after the main types of bariatric surgery. METHODS: Therefore, a systematic review was performed using the electronic literature available in the databases LILACS, CENTRAL, Web of Science, Embase, and PubMed/MEDLINE, with results until January 2021. Keywords were descriptors for bariatric surgery or bariatric medicine or bariatrics or gastroplasty and bone or bones or bone fractures, referenced in all words of the text in the study. RESULTS: The meta-analysis of observational studies and interventional trials showed that the risk of any type of fracture was higher in the surgical group than in the nonsurgical group (relative risk [RR], 1.20 [95% confidence interval {CI}, 1.15-1.26; P < .00001; Phetero < 0.000001; I2 = 94%], and RR, 1.16 [95% CI, 1.00-1.33; P = .04; Phetero = 0.27; I2 = 23%], respectively). It is worth noting that the included interventional studies have a low rating on the risk of bias assessment scales. Compared with those who underwent restrictive procedures, subjects had an increased fracture risk after malabsorptive procedures (RR, 0.49 [95% CI, 0.40-0.61; P < .00001); Phetero = 0.96; I2 = 0%). CONCLUSION: We found that bariatric procedures are associated with an increased risk of fractures, especially the malabsorptive techniques.