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

Bariatric surgery is associated with a postoperative reduction of 25(OH) vitamin D levels (25(OH)D) and with skeletal complications. Currently, guidelines for 25(OH)D assessment and vitamin D supplementation in bariatric patients, pre- and post-surgery, are still lacking. The aim of this work is to analyse systematically the published experience on 25(OH)D status and vitamin D supplementation, pre- and post-surgery, and to propose, on this basis, recommendations for management. Preoperatively, 18 studies including 2,869 patients were evaluated. Prevalence of vitamin D insufficiency as defined by 25(OH)D < 30 ng/mL (75 nmol/L) was 85%, whereas when defined by 25(OH)D < 20 ng/mL (50 nmol/L) was 57%. The median preoperative 25(OH)D level was 19.75 ng/mL. After surgery, 39 studies including 5,296 patients were analysed and among those undergoing either malabsorptive or restrictive procedures, a lower rate of vitamin D insufficiency and higher 25(OH)D levels postoperatively were observed in patients treated with high-dose oral vitamin D supplementation, defined as ≥ 2,000 IU/daily (mostly D3-formulation), compared with low-doses (< 2,000 IU/daily). Our recommendations based on this systematic review and meta-analysis should help clinical practice in the assessment and management of vitamin D status before and after bariatric surgery. Assessment of vitamin D should be performed pre- and postoperatively in all patients undergoing bariatric surgery. Regardless of the type of procedure, high-dose supplementation is recommended in patients after bariatric surgery.

Cholecalciferol Use Is Associated With a Decreased Risk of Incident Morphometric Vertebral Fractures in Acromegaly.

CONTEXT: Skeletal fragility is observed in 30% to 60% of acromegaly patients, representing an emerging complication of the disease that increases disability. Despite several studies having investigated the clinical and hormonal prognostic factors for the occurrence of vertebral fractures (VFs) in acromegaly, very few data are available on their prevention/treatment including the effect of vitamin D (VD) supplementation, which has been reported to have a fracture-protective effect in several studies in patients with osteoporosis. OBJECTIVE: We aimed to investigate the role of cholecalciferol (D3) supplementation in the prevention of incident VFs (i-VFs) in acromegaly. METHODS: A longitudinal, retrospective and multicenter study was performed on 61 acromegaly patients treated and untreated with D3 supplementation. RESULTS: Twenty-six patients were treated with D3 supplementation according to clinical guidelines. The median D3 weekly dosage was 8500 IU (interquartile range [IQR]: 3900). The median duration of D3 supplementation was 94 months (IQR: 38). At last follow-up, i-VFs were diagnosed in 14 patients (23%). I-VFs were less prevalent in patients on D3 supplementation (14.3% of cases) compared to patients not treated with D3 (85.7%; P = .02). The final level of serum V25OH-D was significantly lower in patients who developed i-VFs (28.6 ng/mL, IQR: 4.1) compared to patients who did not develop i-VFs (34.2 ng/mL, IQR: 9.6; P = .05). The logistic regression confirmed the protective role of D3 supplementation on the occurrence of i-VFs (odds ratio: 0.16; 95% CI, 0.03-0.79; P = .01). CONCLUSION: It is likely that D3 supplementation could lead to a reduction in i-VFs in acromegaly.

Lack of vitamin D predicts impaired long-term immune response to COVID-19 vaccination.

PURPOSE: Low vitamin D levels were reported to negatively influence the outcome of acute COVID-19, as well as to be linked to Long-COVID. However, few studies have investigated, so far, its effects on humoral-response to anti-SARS-CoV-2 vaccination, reporting conflicting results. We aimed to evaluate the impact of baseline 25(OH)vitamin D (25(OH)D) levels on humoral-response to a two-dose cycle of Pfizer-BioNTech-vaccine up to 9-10 months after immunization. METHODS: We retrospectively included 119 consecutive healthcare-workers (median age 53 years) without a previous history of acute COVID-19 or anti-SARS-CoV-2 immunoglobulins presence immunized with two doses of Comirnaty-vaccine from January to February 2021. 25(OH)D was measured at time of first-immunization. Immune response was evaluated at: time 0 (T0), before the first-dose; T1, time of second-dose (21 days after T0); T2, T3, T4 at 1, 5 and 9 months after T1, respectively. RESULTS: Median 25(OH)D levels were 25.6 ng/mL, and vitamin D deficiency (25(OH)D <20 ng/mL) was observed in 29 subjects (24.8%). In those with vitamin D deficiency, we found a non-significant trend towards lower antibody-titers at T3, and significantly lower titers at T4 as compared to those not vitamin D-deficient, also observing a more pronounced antibody-titers negative drop from peak-T2 and T4 in those with vitamin D deficiency. A positive correlation between 25(OH)D levels and antibody-titers at T4 (p = 0.043) was found. In multiple linear-regression analysis, 25(OH)D deficiency and older-age resulted as negative independent factors associated with antibody titer at T4 (p = 0.026, p = 0.004; respectively). CONCLUSION: In our relatively young cohort presenting low prevalence of hypovitaminosis D, the long-term humoral response to anti-SARS-CoV-2 vaccination was negatively influenced by low baseline 25(OH)D. Vitamin D supplementation could be tested as a strategy to optimize the vaccination campaigns to prevent severe COVID-19.

Low Vitamin D Levels Are Associated With Long COVID Syndrome in COVID-19 Survivors.

CONTEXT: Long COVID is an emerging syndrome affecting 50% to 70% of COVID-19 survivors that still lacks predicting factors. OBJECTIVE: Due to the extraskeletal effects of vitamin D, we retrospectively assessed the association between 25(OH) vitamin D levels and long COVID in COVID-19 survivors 6 months after hospitalization. METHODS: Long COVID was defined according to NICE guidelines. Fifty long COVID and 50 non-long-COVID subjects matched on a 1:1 basis were enrolled from an outpatient clinic post-COVID cohort seen from August to November 2020. Therapies/comorbidities affecting calcium/vitamin D/bone metabolism, and/or admission to the intensive care unit during hospitalization were exclusion criteria. 25(OH) Vitamin D was measured at hospital admission and 6 months after discharge. RESULTS: We observed lower 25(OH) vitamin D levels, evaluated at follow-up, in subjects with long COVID than those without (20.1 vs 23.2 ng/mL, P = .03). Regarding the affected health areas evaluated in the entire cohort, we observed lower 25(OH) vitamin D levels in those with neurocognitive symptoms at follow-up (n = 7) than those without (n = 93) (14.6 vs 20.6 ng/mL, P = .042). In patients presenting vitamin D deficiency (<20 ng/mL), both at admission and at follow-up (n = 42), those affected by long COVID (n = 22) presented lower 25(OH) vitamin D levels at follow-up than those not affected (n = 20) (12.7 vs 15.2 ng/mL, P = .041). In multiple regression analyses, lower 25(OH) vitamin D levels at follow-up were the only variable significantly associated with long COVID in our cohort (P = .008, OR 1.09, CI 1.01-1.16). CONCLUSION: COVID-19 survivors with long COVID have lower 25(OH) vitamin D levels than matched patients without long COVID. Our data suggest that vitamin D levels should be evaluated in COVID-19 patients after hospital discharge. The role of vitamin D supplementation as a preventive strategy of COVID-19 sequelae should be tested in randomized controlled trials.

Vitamin D and malabsorptive gastrointestinal conditions: A bidirectional relationship?

This paper is one of the outcomes of the 5th International Conference "Controversies in Vitamin D" held in Stresa, Italy from 15 to 18 September 2021 as part of a series of annual meetings which was started in 2017. The scope of these meetings is to discuss controversial issues about vitamin D. Publication of the outcomes of the meeting in international journals allows a wide sharing of the most recent data with the medical and academic community. Vitamin D and malabsorptive gastrointestinal conditions was one of the topics discussed at the meeting and focus of this paper. Participants to the meeting were invited to review available literature on selected issues related to vitamin D and gastrointestinal system and to present their topic to all participants with the aim to initiate a discussion on the main outcomes of which are reported in this document. The presentations were focused on the possible bidirectional relationship between vitamin D and gastrointestinal malabsorptive conditions such as celiac disease, inflammatory bowel diseases (IBDs) and bariatric surgery. In fact, on one hand the impact of these conditions on vitamin D status was examined and on the other hand the possible role of hypovitaminosis D on pathophysiology and clinical course of these conditions was also evaluated. All examined malabsorptive conditions severely impair vitamin D status. Since vitamin D has known positive effects on bone this in turn may contribute to negative skeletal outcomes including reduced bone mineral density, and increased risk of fracture which may be mitigated by vitamin D supplementation. Due to the immune and metabolic extra-skeletal effects there is the possibility that low levels of vitamin D may negatively impact on the underlying gastrointestinal conditions worsening its clinical course or counteracting the effect of treatment. Therefore, vitamin D status assessment and supplementation should be routinely considered in all patients affected by these conditions. This concept is strengthened by the existence of a possible bidirectional relationship through which poor vitamin D status may negatively impact on clinical course of underlying disease. Sufficient elements are available to estimate the desired threshold vitamin D level above which a favourable impact on the skeleton in these conditions may be obtained. On the other hand, ad hoc controlled clinical trials are needed to better define this threshold for obtaining a positive effect of vitamin D supplementation on occurrence and clinical course of malabsorptive gastrointestinal diseases.

Vitamin D in Osteosarcopenic Obesity.

Osteosarcopenic obesity is a unique clinical condition where low bone and muscle mass coexist in individuals with obesity. Alterations in adipose tissue, skeletal muscle and bone are strictly interconnected, and vitamin D plays key roles in several metabolic pathways that are involved in maintaining musculoskeletal health and glucose homeostasis. We reviewed the available literature on mechanisms underlying osteosarcopenic obesity, with a focus on the role of vitamin D in the pathogenesis and treatment of the condition. We found that, although evidence from large observational studies and pre-clinical experiments strongly supports a role of vitamin D deficiency in the pathogenesis of osteosarcopenic obesity, the common belief that vitamin D improves musculoskeletal health lacks solid clinical evidence, as trials specifically aimed at assessing the effects of vitamin D supplementation in patients with osteosarcopenic obesity are not available, and trials that investigated the role of vitamin D on muscle and bone health in other patient populations either showed no or even detrimental effects. We conclude that large observational and interventional studies including individuals with osteosarcopenic obesity representative of different sex, age and race are needed to better define the role of vitamin D in the pathogenesis and treatment of this condition.