# Comparative Impact of Vitamin D Deficiency on Immune Function and Disease Susceptibility in Pediatric Versus Adult Populations

## TL;DR

This study compares how vitamin D deficiency affects immune function and infection rates in children and adults.

## Contribution

The study provides descriptive associations between vitamin D deficiency, immune markers, and infection patterns in pediatric versus adult populations.

## Key findings

- Pediatric participants had lower vitamin D levels, lymphocyte counts, and IgG levels compared to adults.
- Children reported higher frequencies of respiratory and gastrointestinal infections.
- A moderate positive correlation was found between vitamin D levels and lymphocyte counts in both age groups.

## Abstract

Background: Vitamin D deficiency is a common global health problem and has been widely studied in relation to immune function and infectious diseases. Vitamin D receptors are expressed on multiple immune cells, suggesting a potential association between vitamin D status and immune-related parameters. However, comparative observational data examining age-related differences in immune markers and infection patterns among vitamin D-deficient individuals remain limited.

Objective: The study aimed to describe and compare associations between vitamin D deficiency, selected immune markers, and reported infection patterns in pediatric and adult patients.

Methods: This comparative cross-sectional observational study was conducted at a tertiary care hospital. Pediatric (1-18 years) and adult (≥19 years) patients with vitamin D deficiency were included. Serum 25-hydroxyvitamin D levels, immune markers (total lymphocyte count, immunoglobulin levels, C-reactive protein, and erythrocyte sedimentation rate), and reported respiratory and gastrointestinal infections over the preceding six months were assessed. Unadjusted comparisons between pediatric and adult groups were performed using appropriate statistical tests, and associations between vitamin D levels and immune markers were evaluated using correlation analysis.

Results: A total of 120 participants were included, comprising 60 pediatric and 60 adult patients. Pediatric participants had lower measured serum vitamin D levels, lower total lymphocyte counts, and lower IgG levels compared to adult participants. Higher reported frequencies of respiratory and gastrointestinal infections were observed among children. A moderate positive correlation was observed between serum vitamin D levels and total lymphocyte counts across both age groups.

Conclusion: Vitamin D deficiency was associated with differences in selected immune markers and reported infection patterns between pediatric and adult patients. These findings represent descriptive associations observed at a single time point and do not establish causality or directionality. Further longitudinal and interventional studies are required to clarify temporal relationships and clinical significance.