Vitamin D therapy in children with inflammatory bowel disease: A systematic review

Association of selected adipokines with vitamin D deficiency in children with inflammatory bowel disease

BACKGROUND

Adipose tissue is significantly involved in inflammatory bowel disease (IBD). Vitamin D can affect both adipogenesis and inflammation. The aim of this study was to compare the production of selected adipokines, potentially involved in the pathogenesis of IBD - adiponectin, resistin, retinol binding protein 4 (RBP-4), adipocyte fatty acid binding protein and nesfatin-1 in children with IBD according to the presence of 25-hydroxyvitamin D (25(OH)D) deficiency.

METHODS

The study was conducted as a case-control study in pediatric patients with IBD and healthy children of the same sex and age. In addition to adipokines and 25(OH)D, anthropometric parameters, markers of inflammation and disease activity were assessed in all participants.

RESULTS

Children with IBD had significantly higher resistin levels regardless of 25(OH)D levels. IBD patients with 25(OH)D deficiency only had significantly lower RBP-4 compared to healthy controls and also compared to IBD patients without 25(OH)D deficiency. No other significant differences in adipokines were found in children with IBD with or without 25(OH)D deficiency. 25(OH)D levels in IBD patients corelated with RBP-4 only, and did not correlate with other adipokines.

CONCLUSIONS

Whether the lower RBP-4 levels in the 25(OH)D-deficient group of IBD patients directly reflect vitamin D deficiency remains uncertain. The production of other adipokines does not appear to be directly related to vitamin D deficiency.

Patterns of vitamin D testing and supplementation for children with inflammatory bowel disease in Australasia

BACKGROUND AND AIM

For children with inflammatory bowel disease (IBD), optimal levels of vitamin D are ascribed anti-inflammatory and essential immune system roles that are associated with reduced disease activity, lower postoperative recurrence, and higher quality of life. International guidelines for vitamin D testing and supplementation provide inconsistent recommendations. The aim of this study was to survey Australasian pediatric gastroenterologists to ascertain current practices of vitamin D testing and supplementation for children with IBD.

METHODS

Members of the Australian Society of Pediatric Gastroenterology, Hepatology and Nutrition were invited to complete an online survey. Respondents were asked to provide information on frequency of vitamin D testing and supplementation, adherence, and benefits of vitamin D to children with IBD.

RESULTS

Thirty-two (54%) pediatric gastroenterologists completed the survey: 27 (84%) from Australia and 5 (16%) from New Zealand. The majority (90%) tested vitamin D levels at diagnosis and follow up, although testing frequency varied (1-3 times/year) and only 8 (28%) tested seasonally. While 28 (88%) recommended supplementation based on serum levels, inconsistent cutoff values were used. Most respondents (n = 27) recommended Stoss (single dose) or vitamin D3 (daily for 8-12 weeks). The majority (84%) rated the overall benefit of optimal vitamin D levels at ≥6/10, although fewer (54%) rated the benefit to disease activity at ≥6/10.

CONCLUSIONS

The results indicate that standardized guidelines for vitamin D testing and supplementation for clinicians caring for children with IBD throughout Australasia are required. Consensus statements may optimize the care of children with IBD in this diverse geographical region.

Vitamin D for the treatment of inflammatory bowel disease

BACKGROUND

Vitamin D possesses immunomodulatory properties and has been implicated in the pathogenesis and severity of inflammatory bowel disease (IBD). Animal studies and emerging epidemiological evidence have demonstrated an association between vitamin D deficiency and worse disease activity. However, the role of vitamin D for the treatment of IBD is unclear.

OBJECTIVES

To evaluate the benefits and harms of vitamin D supplementation as a treatment for IBD.

SEARCH METHODS

We used standard, extensive Cochrane search methods. The latest search date was Jun 2023.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) in people of all ages with active or inactive IBD comparing any dose of vitamin D with another dose of vitamin D, another intervention, placebo, or no intervention. We defined doses as: vitamin D (all doses), any-treatment-dose vitamin D (greater than 400 IU/day), high-treatment-dose vitamin D (greater than 1000 IU/day), low-treatment-dose vitamin D (400 IU/day to 1000 IU/day), and supplemental-dose vitamin D (less than 400 IU/day).

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were 1. clinical response for people with active disease, 2. clinical relapse for people in remission, 3. quality of life, and 4. withdrawals due to adverse events. Our secondary outcomes were 5. disease activity at end of study, 6. normalisation of vitamin D levels at end of study, and 7. total serious adverse events. We used GRADE to assess certainty of evidence for each outcome.

MAIN RESULTS

We included 22 RCTs with 1874 participants. Study duration ranged from four to 52 weeks. Ten studies enroled people with Crohn's disease (CD), five enroled people with ulcerative colitis (UC), and seven enroled people with CD and people with UC. Seventeen studies included adults, three included children, and two included both. Four studies enroled people with active disease, six enroled people in remission, and 12 enroled both. We assessed each study for risk of bias across seven individual domains. Five studies were at low risk of bias across all seven domains. Ten studies were at unclear risk of bias in at least one domain but with no areas of high risk of bias. Seven studies were at high risk of bias for blinding of participants and assessors. Vitamin D (all doses) versus placebo or no treatment Thirteen studies compared vitamin D against placebo or no treatment. We could not draw any conclusions on clinical response for UC as the certainty of the evidence was very low (risk ratio (RR) 4.00, 95% confidence interval (CI) 1.51 to 10.57; 1 study, 60 participants). There were no data on CD. There may be fewer clinical relapses for IBD when using vitamin D compared to placebo or no treatment (RR 0.57, 95% CI 0.34 to 0.96; 3 studies, 310 participants). The certainty of the evidence was low. We could not draw any conclusions on quality of life for IBD (standardised mean difference (SMD) -0.13, 95% CI -3.10 to 2.83 (the SMD value indicates a negligent decrease in quality of life, and the corresponding CIs indicate that the effect can range from a large decrease to a large increase in quality of life); 2 studies, 243 participants) or withdrawals due to adverse events for IBD (RR 1.97, 95% CI 0.18 to 21.27; 12 studies, 1251 participants; note 11 studies reported withdrawals but recorded 0 events in both groups. Thus, the RR and CIs were calculated from 1 study rather than 12). The certainty of the evidence was very low. High-treatment-dose vitamin D versus low-treatment-dose vitamin D Five studies compared high treatment vitamin D doses against low treatment vitamin D doses. There were no data on clinical response. There may be no difference in clinical relapse for CD (RR 0.48, 95% CI 0.23 to 1.01; 1 study, 34 participants). The certainty of the evidence was low. We could not draw any conclusions on withdrawals due to adverse events for IBD as the certainty of the evidence was very low (RR 0.89, 95% CI 0.06 to 13.08; 3 studies, 104 participants; note 2 studies reported withdrawals but recorded 0 events in both groups. Thus, the RR and CIs were calculated from 1 study rather than 3). The data on quality of life and disease activity could not be meta-analysed, were of very low certainty, and no conclusions could be drawn. Any-treatment-dose vitamin D versus supplemental-dose vitamin D Four studies compared treatment doses of vitamin D against supplemental doses. There were no data on clinical response and relapse. There were no data on quality of life that could be meta-analysed. We could not draw any conclusions on withdrawals due to adverse events for IBD as the certainty of the evidence was very low (RR 3.09, 95% CI 0.13 to 73.17; 4 studies, 233 participants; note 3 studies reported withdrawals but recorded 0 events in both groups. Thus, the RR and CIs were calculated from 1 study rather than 4).

AUTHORS' CONCLUSIONS

There may be fewer clinical relapses when comparing vitamin D with placebo, but we cannot draw any conclusions on differences in clinical response, quality of life, or withdrawals, due to very low-certainty evidence. When comparing high and low doses of vitamin D, there were no data for clinical response, but there may be no difference in relapse for CD. We cannot draw conclusions on the other outcomes due to very low certainty evidence. Finally, comparing vitamin D (all doses) to supplemental-dose vitamin D, there were no data on clinical relapse or response, and we could not draw conclusions on other outcomes due to very low certainty evidence or missing data. It is difficult to make any clear recommendations for future research on the basis of the findings of this review. Future studies must be clear on the baseline populations, the purpose of vitamin D treatment, and, therefore, study an appropriate dosing strategy. Stakeholders in the field may wish to reach consensus on such issues prior to new studies.

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.

Association between vitamin D level and pediatric inflammatory bowel disease: A systematic review and meta-analysis

Background

Previous studies have reported that the incidence of pediatric inflammatory bowel disease (IBD) is related to vitamin D, but it is still unclear. This study intends to calculate the relationship between pediatric IBD and vitamin D.

Methods

A comprehensive literature search from inception to January 2023 was performed in the PubMed, EMBASE, Medline, Web of Science, and Google Scholar databases. Relevant data were extracted as required and used for subsequent calculations.

Results

Sixteen papers were included, and there was no significant difference between the average vitamin D level in IBD patients and healthy controls. In addition, the overall pooled results showed that C-reactive protein (CRP) was 2.65 higher before vitamin D supplementation than after supplementation [SMD = 2.65, 95% CI = (2.26, 3.04)]. Moreover, patients with IBD in remission were 0.72 higher before vitamin D supplementation than after supplementation [OR = 0.72, 95% CI = (0.52, 1.00)].

Conclusion

This study suggested that there was no obvious relationship between pediatric IBD and vitamin D, while vitamin D supplementation can improve disease activity. Therefore, follow-up still needs many prospective studies to confirm the relationship between pediatric IBD and vitamin D.

25(OH)Vitamin D Deficiency and Calcifediol Treatment in Pediatrics

Vitamin D is essential for the normal mineralization of bones during childhood. Although diet and adequate sun exposure should provide enough of this nutrient, there is a high prevalence of vitamin D deficiency rickets worldwide. Children with certain conditions that lead to decreased vitamin D production and/or absorption are at the greatest risk of nutritional rickets. In addition, several rare genetic alterations are also associated with severe forms of vitamin-D-resistant or -dependent rickets. Although vitamin D3 is the threshold nutrient for the vitamin D endocrine system (VDES), direct measurement of circulating vitamin D3 itself is not a good marker of the nutritional status of the system. Calcifediol (or 25(OH)D) serum levels are used to assess VDES status. While there is no clear consensus among the different scientific associations on calcifediol status, many clinical trials have demonstrated the benefit of ensuring normal 25(OH)D serum levels and calcium intake for the prevention or treatment of nutritional rickets in childhood. Therefore, during the first year of life, infants should receive vitamin D treatment with at least 400 IU/day. In addition, a diet should ensure a normal calcium intake. Healthy lifestyle habits to prevent vitamin D deficiency should be encouraged during childhood. In children who develop clinical signs of rickets, adequate treatment with vitamin D and calcium should be guaranteed. Children with additional risk factors for 25(OH)D deficiency and nutritional rickets should be assessed periodically and treated promptly to prevent further bone damage.

Efficacy and Safety of High-dose Cholecalciferol in Patients With Inflammatory Bowel Disease Receiving Infliximab

OBJECTIVE

Vitamin D deficiency is prevalent in patients with inflammatory bowel disease (IBD). The goal of this study was to assess the efficacy and safety of high-dose, interval cholecalciferol administration in patients with IBD receiving infliximab.

METHODS

This prospective, longitudinal, open-label study enrolled pediatric and young adult patients with IBD and vitamin D deficiency. Subjects received 50,000 IU every 4 to 5 weeks (n = 11) or 100,000 IU every 6 to 8 weeks (n = 32) of oral cholecalciferol for 1 year. Dosing was directly observed and administered in conjunction with infliximab infusions. The primary endpoint was vitamin D sufficiency, defined as a 25-hydroxy-vitamin D (25-OHD) level ≥30 ng/mL.

RESULTS

Forty-three participants constituted the primary analysis population. 25-OHD levels reached steady-state after the third dose, and mean increases in 25-OHD levels were 8 vs. 4.5 ng/mL in the 100,000 IU vs. 50,000 IU treatment groups, respectively. Only 43.8% of patients receiving 100,000 IU and 18.2% of patients receiving 50,000 IU achieved sufficiency. There was no difference in the 25-OHD level responsiveness in patients with Crohn disease versus those with ulcerative colitis (P = 0.72). There was no correlation between 25-OHD levels and clinical disease activity in patients with Crohn disease (P = 0.85) or ulcerative colitis (P = 0.24).

CONCLUSIONS

Supplementation with cholecalciferol was well-tolerated and direct observation is a promising paradigm for ensuring compliance with therapy. Patients with IBD, however, appear to require high doses of cholecalciferol, with less than half of patients (37% overall) achieving vitamin D sufficiency. Additional studies are necessary to determine the optimal treatment regimens.

Metabolic Bone Disorders in Children with Inflammatory Bowel Diseases

In recent years, there has been a noticeable increase in the incidence of inflammatory bowel diseases in the pediatric population. Entry observations demonstrate anemia, malabsorption, deficiencies in vitamin D and calcium. These aspects, together with the systemic action of pro-inflammatory cytokines and steroid therapy are widely recognized as factors influencing bone metabolism. Presently, however, there are very few studies that can be found in the scientific literature on metabolic disorders in patients with IBD, especially in the pediatric population as the coexistence has not been sufficiently examined and understood. This review aims to summarize the currently available literature, as well as assess which areas have information gaps and need further research.

Diet, Sun, Physical Activity and Vitamin D Status in Children with Inflammatory Bowel Disease

In the course of inflammatory bowel disease (IBD) malabsorption may lead to a vitamin D deficiency and calcium–phosphate misbalance. However, the reports on the vitamin D status in children with IBD are few and ambiguous. Here, we are presenting complex analyses of multiple factors influencing 25OHD levels in IBD children (N = 62; Crohn’s disease n = 34, ulcerative colitis n = 28, mean age 14.4 ± 3.01 years, F/M 23/39) and controls (n = 47, mean age 13.97 ± 2.57, F/M 23/24). Additionally, calcium–phosphate balance parameters and inflammatory markers were obtained. In children with IBD disease, activity and location were defined. Information about therapy, presence of fractures and abdominal surgery were obtained from medical records. All subjects were surveyed on the frequency and extent of exposure to sunlight (forearms, partially legs for at least 30 min a day), physical activity (at least 30 min a day) and diet (3 days diary was analyzed with the program DIETA 5). The mean 25OHD level was higher in IBD patients compared to controls (18.1 ng/mL vs. 15.5 ng/mL; p = 0.03). Only 9.7% of IBD patients and 4.25% of controls had the optimal vitamin D level (30–50 ng/mL). Despite the higher level of 25OHD, young IBD patients showed lower calcium levels in comparison to healthy controls. There was no correlation between the vitamin D level and disease activity or location of gastrointestinal tract lesions. Steroid therapy didn’t have much influence on the vitamin D level while vitamin D was supplemented. Regular sun exposure was significantly more common in the control group compared to the IBD group. We found the highest concentration of vitamin D (24.55 ng/mL) with daily sun exposure. There was no significant correlation between the vitamin D level and frequency of physical activity. The analysis of dietary diaries showed low daily intake of vitamin D in both the IBD and the control group (79.63 vs. 85.14 IU/day). Pediatric patients, both IBD and healthy individuals, require regular monitoring of serum vitamin D level and its adequate supplementation.

Bone Health in Pediatric Patients with IBD: What Is New?

PURPOSE OF THE REVIEW

Patients with inflammatory bowel disease (IBD) have increased bone fragility, demonstrated by increased fracture risk, and often have low bone density and altered bone geometry, but the underlying pathophysiology remains poorly understood.

RECENT FINDINGS

Children and adolescents with IBD appear to have decreased bone formation, at diagnosis, which frequently improves with treatment of their underlying IBD. There is a growing body of evidence regarding how the immune system interacts with bone metabolism. There are likely multi-factorial etiologies that contribute to suboptimal bone accrual and subsequent lack of peak bone mass attainment in growing patients with IBD. There appears to be differential effects dependent upon IBD sub-type and bone compartment. Pediatric patients with IBD require recognition of several risk factors that may adversely impact their bone accrual. Future studies are necessary to further delineate the effects of IBD on pediatric bone health.

Hypocalcemia and Vitamin D Deficiency in Children with Inflammatory Bowel Diseases and Lactose Intolerance

Background: A diet restricted in dairy products can cause calcium and vitamin D deficiency and, secondarily, lead to malnutrition and low bone mass. The aim of the study was to determine the incidence hypocalcemia and vitamin D deficiency in children with inflammatory bowel diseases and lactose intolerance (LI). Material and Methods: A total of 107 patients were enrolled to the study (mean age 14.07 ± 3.58 years; 46.7% boys): 43 with Crohn’s disease (CD), 31 with ulcerative colitis (UC), and 33 with functional abdominal pain (AP-FGID). Hydrogen breath test with lactose and laboratory tests to assess the calcium-phosphate metabolism were performed in all patients. The results of densitometry were interpreted in 37 IBD patients. Results: LI was diagnosed in 23.2% patients with CD, 22.6% with UC, and 21.2% children with AP-FGID, (p = 0.9). Moreover, 9.5% patients with CD, in 21.4% with UC, and in 51.5% with AP-FGID had optimal concentration of 25(OH)D (p = 0.0002). Hypocalcemia was diagnosed in 21% of patients with CD, 16.1% with UC patients, AP-FGID patients had normal calcium levels (p = 0.02). There was no difference in concentrations of total calcium, phosphorus, and 25(OH)D between patients on low-lactose diet and normal diet (p > 0.05). BMD Z-score ≤ −1 SD was obtained by 12 CD patients (48%), and 6 with UC (50%). Conclusion: The use of a low-lactose diet in the course of lactose intolerance in children with inflammatory bowel diseases has no effect on the incidence of calcium-phosphate disorders and reduced bone mineral density.

Sarcopenia and Vitamin D Deficiency in Patients with Crohn's Disease: Pathological Conditions That Should Be Linked Together

Sarcopenia is a prevalent condition in patients with Crohn’s disease (CD), representing an independent predictor factor for the development of major postoperative complications. Thus, a proper assessment of the muscle strength, by using different validated tools, should be deemed an important step of the clinical management of these patients. Patients with CD are frequently malnourished, presenting a high prevalence of different macro- and micro-nutrient deficiencies, including that of vitamin D. The available published studies indicate that vitamin D is involved in the regulation of proliferation, differentiation, and regeneration of muscle cells. The relationship between vitamin D deficiency and sarcopenia has been extensively studied in other populations, with interesting evidence in regards to a potential role of vitamin D supplementation as a means to prevent and treat sarcopenia. The aim of this review was to find studies that linked together these pathological conditions.

Vitamin D Therapy in Adults With Inflammatory Bowel Disease: A Systematic Review and Meta-Analysis

BACKGROUND

Vitamin D deficiency has been implicated in the pathogenesis of inflammatory bowel disease. Emerging literature suggests that optimization of vitamin D levels may be associated with improvements in disease activity and quality of life. We conducted a meta-analysis exploring the effect of vitamin D on serum 25-hydroxyvitamin D (s-25[OH]D) levels, clinical improvement, and biomarkers.

METHODS

MEDLINE, EMBASE, the Cochrane Library, and sources for grey literature were searched from inception until September 2019. The primary outcome was s-25(OH)D mean differences. Heterogeneity was assessed using the χ 2 test and the I2 statistic. Review Manager software v. 5.3 was used.

RESULTS

Twelve randomized controlled trials (n = 611) and 4 observational studies (n = 359) were included in the meta-analysis. On average, in the randomized controlled trials, vitamin D supplementation increased s-25(OH)D levels by 15.50 ng/mL (95% confidence interval [CI], 11.08-19.92, P ≤ 0.00001, I2 = 90%) and in observational studies they increased by 18.39 ng/mL (95% CI, 8.91-27.88, P = 0.0001, I2 = 82%). Subgroup analyses between vitamin D and placebo groups revealed that vitamin D increased s-25(OH)D by 14.85 ng/mL (95% CI, 9.96-19.73, P ≤ 0.00001, I2 = 90%) and when high doses of vitamin D were compared with low doses, high doses increased s-25(OH)D by 18.27 ng/mL (95% CI, 5.44-31.10, P = 0.005, I2 = 90%). The Harvey Bradshaw Index improved by -1.47 points (95% CI, -2.47 to -0.47, P = 0.004, I2 = 0%) and the high-sensitivity C-reactive protein decreased by -1.58 mg/L (95% CI, -2.95 to -0.21, P = 0.02, I2 = 0%).

CONCLUSIONS

Vitamin D supplementation in patients with IBD and vitamin D deficiency is effective at correcting vitamin D levels and is associated with improvement in clinical and biochemical disease activity scores.

Reference values of 25-hydroxyvitamin D revisited: a position statement from the Brazilian Society of Endocrinology and Metabolism (SBEM) and the Brazilian Society of Clinical Pathology/Laboratory Medicine (SBPC)

Hypovitaminosis D is a common condition with a negative impact on health. This statement, prepared by experts from the Brazilian Society of Endocrinology and Metabolism and the Brazilian Society of Clinical Pathology/Laboratory Medicine, includes methodological aspects and limitations of the measurement of 25-hydroxyvitamin D [25(OH)D] for identification of vitamin D status, and identifies individuals at increased risk for deficiency of this vitamin in whom 25(OH)D measurement is recommended. For the general population, 25(OH)D levels between 20 and 60 ng/mL are considered normal, while individuals with levels below 20 ng/mL are considered to be vitamin D deficient. This statement identifies potential benefits of maintaining 25(OH)D levels > 30 ng/mL in specific conditions, including patients aged > 65 years or pregnant, those with recurrent falls, fragility fractures, osteoporosis, secondary hyperparathyroidism, chronic kidney disease, or cancer, and individuals using drugs with the potential to affect the vitamin D metabolism. This statement also calls attention to the risk of vitamin D intoxication, a life-threatening condition that occurs at 25(OH)D levels above 100 ng/mL.

Systematic review with meta-analysis: association of vitamin D status with clinical outcomes in adult patients with inflammatory bowel disease

BACKGROUND

Vitamin D deficiency is highly prevalent among patients with IBD, however, data on its association with clinical outcomes are conflicting.

AIM

To perform a systematic review and meta-analysis to explore the association of low vitamin D status with clinical outcomes in patients with IBD.

METHODS

We searched PubMed, Embase, Scopus and Web of Science from inception to February 2018 for observational studies evaluating the association of low 25(OH)D status on IBD disease activity, mucosal inflammation, clinical relapse and quality of life. Odds ratios (ORs) were pooled and analysed using a random effects model.

RESULTS

Twenty-seven studies were eligible for inclusion comprising 8316 IBD patients (3115 ulcerative colitis, 5201 Crohn's disease). Among IBD patients, low 25(OH)D status was associated with increased odds of disease activity (OR 1.53, 95% CI 1.32-1.77, I²  = 0%), mucosal inflammation (OR 1.25, 95% CI 1.06-1.47, I²  = 0%), low quality of life (QOL) scores (OR 1.30, 95% CI 1.06-1.60, I²  = 0%) and future clinical relapse (OR 1.23, 95% CI 1.03-1.47, I²  = 0%). In subgroup analysis, low vitamin D status was associated with Crohn's disease activity (OR 1.66, 95% CI 1.36-2.03, I²  = 0%), mucosal inflammation (OR 1.39, 95% CI 1.03-1.85, I²  = 0%), clinical relapse (OR 1.35, 95% CI 1.14-1.59, I²  = 0%), and low QOL scores (OR 1.25, 95% CI 1.04-1.50, I²  = 0%) and ulcerative colitis disease activity (OR 1.47, 95% CI 1.03-2.09, I²  = 0%) and clinical relapse (OR 1.20, 95% 1.01-1.43, I²  = 0%).

CONCLUSIONS

Low 25(OH)D status is a biomarker for disease activity and predictor of poor clinical outcomes in IBD patients.