The association between vitamin D status and inflammatory bowel disease among children and adolescents: A systematic review and meta-analysis.

Frontiers in nutrition. 2022;9:1007725
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Plain language summary

Vitamin D deficiency is often seen in children with inflammatory bowel disease (IBD). This meta-analysis of 35 different studies aimed to determine the relationship between blood vitamin D levels and IBD in children. The results showed that compared to healthy controls, individuals with IBD had slightly but not significantly lower vitamin D levels. It was unclear how different classifications of the disease i.e whether the disease manifests as diarrhoea, constipation, or a mixture of both, may affect vitamin D levels. The paper concluded that vitamin D levels may be slightly lower in children with IBD. This study can be used by healthcare professionals to understand that some children with IBD may have lower than normal vitamin D levels, however it does not provide justification to measure these without further clinical signs of deficiency.

Expert Review


Conflicts of interest: None

Take Home Message:
  • Without further research, justification to measure vitamin D levels in children with IBD would require other clinical signs of deficiency.

Evidence Category:
  • X A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)
  • B: Systematic reviews including RCTs of limited number
  • C: Non-randomized trials, observational studies, narrative reviews
  • D: Case-reports, evidence-based clinical findings
  • E: Opinion piece, other

Summary Review:
Introduction

The aim of the study was to determine the relationship between serum vitamin D levels and paediatric inflammatory bowel disease (IBD).

Methods

  • This systematic review and meta-analysis of 35 case-control, cross-sectional or cohort studies followed PRISMA and MOOSE guidelines
  • Five different libraries were searched
  • 4803 children were included with the majority from the United States, and the remainder from Australia, Finland, Denmark, Italy, South Korea, and Israel.

Results

  • 16 studies were appropriate for meta-analysis and showed a trend of lower vitamin D levels in children with IBD compared to healthy controls, but this was not statistically significant (-1.159 ng/ml; 95% CI: -2.783, 0.464)
  • 18 studies with 2602 children showed that the prevalence of vitamin D deficiency or insufficiency was 44% (95% CI: -0.34- 0.54)
  • There was significant heterogeneity between the prevalence studies (P=<0.001; I2=97.31%) as they included children with different classifications of IBD such as ulcerative colitis and Crohn’s Disease and used different assessments of serum vitamin D levels
  • A strength was that most studies included in the systematic review and meta-analysis were of high quality.

Conclusion

  • There is a non-significant trend towards lower serum vitamin D levels in children with IBD.

Clinical practice applications:
  • Practitioners could consider measuring serum vitamin D levels in children with IBD
  • However, as vitamin D levels were not lower in children with IBD in the present paper, practitioners should be aware that lower vitamin D concentrations may be due to other factors
  • Furthermore, heterogeneity in the study means that it is unclear as to how different forms of the disease may affect levels
  • Vitamin D regulates the immune response and as this is an immune disease, a better understanding of levels may be beneficial.

Considerations for future research:
  • Future research could consider the effect of supplementary vitamin D intakes on IBD symptoms.

Abstract

AIM: Vitamin D deficiency is very common among children with IBD. Since there are conflicting results regarding the association of vitamin D with IBD, we conducted this systematic review to confirm the association of vitamin D with IBD. METHODS We conducted a systematic search in Scopus, Cochrane Library, Web of Science, PubMed, and Google Scholar to find relevant studies. Articles with cross-sectional and case-control designs that reported the association between vitamin D and IBD among children were included. RESULTS Eventually, 9 studies (with 16 effect sizes) reported the mean and SD or the median and the interquartile range of serum vitamin D levels in both subjects with IBD and control subjects. The random effects meta-analysis revealed that subjects with IBD had -1.159 ng/ml (95% CI: -2.783, 0.464) lower serum vitamin D concentrations compared with their healthy counterparts, but this difference was not significant. A total of 14 studies (with 18 effect sizes) with 2,602 participants provided information for the prevalence of vitamin D deficiency or insufficiency in patients with IBD as 44% (95% CI: 0.34-0.54) with significant heterogeneity noted among studies (p < 0.001; I2 = 97.31%). CONCLUSION This systematic and meta-analysis study revealed that vitamin D deficiency was associated with IBD. Longitudinal studies should be conducted in the future to confirm our findings. Large randomized controlled trials assessing the doses of supplementation of vitamin D would provide a better understanding of the association between vitamin D and IBD.

Lifestyle medicine

Patient Centred Factors : Mediators/Inflammation
Environmental Inputs : Nutrients
Personal Lifestyle Factors : Nutrition
Functional Laboratory Testing : Not applicable

Methodological quality

Jadad score : Not applicable
Allocation concealment : Not applicable
Publication Type : Systematic Review

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