Vitamin D status and supplementation before and after Bariatric Surgery: Recommendations based on a systematic review and meta-analysis

Bone health in adults with obesity before and after interventions to promote weight loss

Obesity and its associated comorbidities constitute a serious and growing public health burden. Fractures affect a substantial proportion of people with obesity and result from reduced bone strength relative to increased mechanical loading, together with an increased risk of falls. Factors contributing to fractures in people with obesity include adverse effects of adipose tissue on bone and muscle and, in many people, the coexistence of type 2 diabetes. Strategies to reduce weight include calorie-restricted diets, exercise, bariatric surgery, and pharmacological interventions with GLP-1 receptor agonists. However, although weight loss in people with obesity has many health benefits, it can also have adverse skeletal effects, with increased bone loss and fracture risk. Priorities for future research include the development of effective approaches to reduce fracture risk in people with obesity and the investigation of the effects of GLP-1 receptor agonists on bone loss resulting from weight reduction.

[When should a patient with obesity be referred to endocrinology? Current indications for bariatric surgery]

Bariatric surgery (BS) has been shown to be effective and efficient, but only 1% of selected patients will ever receive it. Compared to medical treatment of obesity, BS has demonstrated greater long-term sustained weight loss, a reduction in both total and cardiovascular (CV) mortality, improvement or remission of CV risk factors and other comorbidities associated with obesity, as well as improved mobility and quality of life. BS presents similar risks to other abdominal surgeries, with obesity as an added risk factor. However, mortality after this type of surgery is less than 1%, being in specialised centres even lower than 0.3%, with a morbidity of less than 7%. The most commonly performed surgical procedures at present are vertical gastrectomy and Roux---Y gastric bypass, preferably by laparoscopic approach.

Efficacy of multivitamin support following bariatric surgery in patients with obesity: a prospective observational study

PURPOSE

Bariatric surgery (BS), an effective treatment for severe obesity and its comorbidities, may result in micronutrient and vitamin deficiencies. This monocentric prospective observational study aimed at evaluating the efficacy of a specifically designed vitamin/mineral formula (Bariatrifast, BIOITALIA S.r.l., Italy) for preventing and treating micronutrient deficiencies in patients submitted to BS.

METHODS

Twenty patients with severe obesity (mean weight and BMI: 123.5 kg (range 88-174) and 43.3 kg/m2 (range 37-54) respectively) underwent BS (10 vertical sleeve gastrectomy VSG, 10 Roux-en-Y gastric bypass, RYGB). The mean age was 49.9 years (range 27-68). After a presurgical visit (V0), follow-up visits were performed at 1, 3, 6 and 12 months after surgery (V1-V4). Recorded data included weight, height and BMI. A complete blood count, measurement of ferritin, folic acid, vitamin B12, ionized calcium, 25 OH vitamin D, parathyroid hormone (PTH) were obtained. Following BS, patients started the daily oral multivitamin and mineral supplement.

RESULTS

All patients achieved a significant weight loss (mean - 34.7 ± 11.8 kg). No deficiencies of various vitamins/micronutrients were detected during the entire study period. The serum concentrations of vitamin B12, 25-OH Vitamin D and folic acid increased over the follow-up period compared with V0 (mean increase 243 ng/L, 23 µg /L, 8 µg/L, respectively). Compared to RYGB, patients who underwent sleeve gastrectomy showed higher levels of 25-OH vitamin D at V2, V3 and V4 (all p < 0.05), and higher levels of Vitamin B12 and folic acid at V4 (p < 0.05 and p < 0.005, respectively). No adverse events were reported.

CONCLUSION

Following VSG or RYGB, Bariatrifast administration was associated with normal values of essential micronutrients, and it was well-tolerated without evidence of gastrointestinal side effects. Clinical Trial Registration ClinicalTrials.gov, identifiers NCT06152965.

Consensus Statement on Vitamin D Status Assessment and Supplementation: Whys, Whens, and Hows

The 6th International Conference, "Controversies in Vitamin D," was convened to discuss controversial topics, such as vitamin D metabolism, assessment, actions, and supplementation. Novel insights into vitamin D mechanisms of action suggest links with conditions that do not depend only on reduced solar exposure or diet intake and that can be detected with distinctive noncanonical vitamin D metabolites. Optimal 25-hydroxyvitamin D (25(OH)D) levels remain debated. Varying recommendations from different societies arise from evaluating different clinical or public health approaches. The lack of assay standardization also poses challenges in interpreting data from available studies, hindering rational data pooling and meta-analyses. Beyond the well-known skeletal features, interest in vitamin D's extraskeletal effects has led to clinical trials on cancer, cardiovascular risk, respiratory effects, autoimmune diseases, diabetes, and mortality. The initial negative results are likely due to enrollment of vitamin D-replete individuals. Subsequent post hoc analyses have suggested, nevertheless, potential benefits in reducing cancer incidence, autoimmune diseases, cardiovascular events, and diabetes. Oral administration of vitamin D is the preferred route. Parenteral administration is reserved for specific clinical situations. Cholecalciferol is favored due to safety and minimal monitoring requirements. Calcifediol may be used in certain conditions, while calcitriol should be limited to specific disorders in which the active metabolite is not readily produced in vivo. Further studies are needed to investigate vitamin D effects in relation to the different recommended 25(OH)D levels and the efficacy of the different supplementary formulations in achieving biochemical and clinical outcomes within the multifaced skeletal and extraskeletal potential effects of vitamin D.

New insights into the vitamin D/PTH axis in endocrine-driven metabolic bone diseases

BACKGROUND

Endocrine regulation of bone metabolisms is the focus of the "Skeletal Endocrinology" series of meetings.

AIMS

To report on the outcome of the discussion on the role of vitamin D/PTH axis in endocrine osteopathies held during the 10th Skeletal Endocrinology Meeting which took place in Stresa (Italy) in March 2023.

OUTCOMES

Vitamin D/PTH axis has relevant influence on several outcomes in the general population and in patients affected by endocrinopathies such as hypoparathyroidism and secreting pituitary adenomas.

CONCLUSIONS

Assessing the status of the vitamin D/PTH axis and using vitamin D and PTH as therapeutic agents is mandatory in several endocrine-related bone metabolic conditions.

Fixed prosthodontic rehabilitation of a patient after bariatric surgery using a facially driven fully digital workflow: A clinical report with a 3-year follow-up

Patients who have received bariatric surgery have specific and complex dental needs. After surgery, nutrient deficiencies, osteoporosis, gastroesophageal reflux, and changes to the oral cavity may be seen, and erosion, caries, wear, xerostomia, hypersensitivity, and changes to the salivary buffering capacity may occur. In addition, patients are advised to ingest smaller, more frequent, meals throughout the day, and the oral condition may decline rapidly after surgery. Without oversight, this accelerated decline may even necessitate complete mouth rehabilitation postoperatively. Dental providers should be an integral part of the multidisciplinary management team of these patients. This clinical report describes a patient with a terminal dentition following bariatric surgery who underwent prosthodontic rehabilitation with a facially driven fully digital workflow.

Hypovitaminosis D and hyperparathyroidism: a 5-year postoperative follow-up of 30,458 gastric bypass and sleeve gastrectomy patients

BACKGROUND

Bariatric procedures are associated with nutrient deficiencies. Studies show an association between gastric bypass (Roux-en-Y gastric bypass [RYGB]) and hypovitaminosis D as well as hyperparathyroidism, yet few compare RYGB to sleeve gastrectomy (SG), and large long-term analyses are scarce.

OBJECTIVE

Evaluate trends of vitamin D and parathyroid hormone (PTH) levels in RYGB and SG.

SETTING

National quality register.

METHOD

The Scandinavian Obesity Surgery Registry records all bariatric surgeries in Sweden. Data from 2008 to 2021 on primary RYGB or SG with reported 25-hydroxy vitamin D (25-OH-D) and/or PTH levels were included. Individuals with an estimated glomerular filtration rate of <60 mL/min/1.73 m2 were excluded, leaving a study population of 25,385 RYGB and 5073 SG patients.

RESULTS

A decrease in 25-OH-D, mirrored by an increase in PTH, was observed after the first year for both procedures, but more pronounced in RYGB. At 5 years, 25-OH-D levels were still higher than at baseline. Regular supplementation resulted in better 25-OH-D and PTH levels. Linear regression found that procedure type (RYGB versus SG), 25-OH-D levels, and time since surgery were significant factors in predicting PTH levels. The risk of pathologic PTH levels (>7 pmol/L) at 2 and 5 years postoperatively was roughly three times higher in RYGB (odds ratios = 3.41 and 2.84, respectively).

CONCLUSIONS

Previous studies alongside these results suggest that RYGB, more so than SG, may cause hypovitaminosis D and thereby hyperparathyroidism, which could lead to osteopenia. The threshold for 25-OH-D should be >75 nmol/L, and despite higher levels, current vitamin D supplementation may not be sufficient. Follow-up should include screening for hyperparathyroidism and hypovitaminosis D.

Dynamic Evaluation of Vitamin D Metabolism in Post-Bariatric Patients

BACKGROUND

findings from the previously conducted studies indicate altered regulatory mechanisms of calcium and vitamin D metabolism in obese patients and a role for bariatric surgery in regulating vitamin D metabolism; however, the available data is controversial and does not provide an adequate understanding of the subject.

METHODS

we evaluated serum parameters of vitamin D and mineral metabolism (vitamin D metabolites (25(OH)D3, 25(OH)D2, 1,25(OH)2D3, 3-epi-25(OH)D3, and 24,25(OH)2D3), vitamin D-binding protein (DBP), free 25(OH)D, fibroblast growth factor 23 (FGF-23), parathyroid hormone (PTH), total calcium, albumin, phosphorus, creatinine, magnesium) in 30 patients referred for bariatric surgery in comparison with 30 healthy volunteers of similar age, sex and baseline 25(OH)D3. Patients were also followed up with repeated laboratory assessments 3 months and 6 months after surgery. During the first 3 months, patients were prescribed high-dose cholecalciferol therapy (50,000 IU per week), with subsequent correction based on the results of the 3-month visit examination.

RESULTS

Preoperatively, patients with morbid obesity were characterized by a high prevalence of vitamin D deficiency (median 25(OH)D3 level 11.9 (6.8; 22.2) ng/mL), significantly lower levels of active vitamin D metabolite 1,25(OH)2D3 (20 (10; 37) vs. 39 (33; 50) pg/mL, p < 0.001), lower serum albumin-adjusted calcium levels (2.24 (2.20; 2.32) vs. 2.31 (2.25; 2.35) mmol/L, p = 0.009) and magnesium levels (0.79 (0.72; 0.82) vs. 0.82 (0.78; 0.85) mmol/L, p = 0.043) with simultaneous similar PTH levels (p = 0.912), and higher DBP levels (328 (288; 401) vs. 248 (217; 284) mg/L, p < 0.001). The 25(OH)D3 levels remained suboptimal (24.5 (14.7; 29.5) ng/mL at the 3-month visit and 17.9 (12.4; 21.0) ng/mL at the 6-month visit, p = 0.052) despite recommended high-dose cholecalciferol supplementation. Patients also demonstrated an increase in 1,25(OH)2D3 levels (38 (31; 52) pg/mL at the 3-month visit and 49 (29; 59) pg/mL at the 6-month visit, p < 0.001) without a change in PTH or calcium levels during the follow-up.

CONCLUSION

our results of a comprehensive laboratory evaluation of vitamin D status and mineral metabolism in patients undergoing bariatric surgery highlight the importance of improving current clinical guidelines, as well as careful monitoring and education of patients.