Vitamin D Deficiency and Severe Dengue Fever: A Systematic Review and Meta-Analysis

Area of Science:

• Immunology
• Infectious Diseases
• Nutritional Science

Background:

• Vitamin D plays a role in immune function, with potential implications for dengue severity.
• Existing evidence on the association between vitamin D levels and dengue severity is inconsistent.

Purpose of the Study:

• To systematically review and meta-analyze observational studies comparing vitamin D levels in severe versus non-severe dengue cases.
• To investigate potential associations between vitamin D deficiency and dengue severity, with a focus on subgroup analyses.

Main Methods:

• Systematic literature search for observational studies comparing vitamin D levels in severe and non-severe dengue.
• Random-effects meta-analysis to pool odds ratios (OR) for severe dengue with vitamin D deficiency.
• Quantification of heterogeneity using I2, with subgroup and sensitivity analyses performed.

Main Results:

• Six studies with 1,130 participants were included in the meta-analysis.
• The initial pooled OR for severe dengue with vitamin D deficiency was 1.77 (95% CI: 0.75-4.16), with substantial heterogeneity (I2 = 61.6%).
• A significant association was found in a subgroup analysis of children (OR: 51.20, 95% CI: 3.12-842.95).
• Excluding an outlier study resulted in a significant fixed-effect OR of 1.67 (95% CI: 1.04-2.67) with reduced heterogeneity (I2 = 46.1%).

Conclusions:

• Vitamin D deficiency may be associated with increased odds of severe dengue, especially in pediatric populations.
• The findings suggest a potential link, but confirmation requires larger, well-designed studies.
• Prospective studies are necessary to establish causality and evaluate the efficacy of vitamin D supplementation in high-risk groups.