Vitamin D Deficiency Associated With Increased Incidence of Gastrointestinal and Ear Infections in School-age Children

Kathryn A. Thornton, DMD, MPH; Constanza Marín, RD; Mercedes Mora-Plazas, MSc, RD; Eduardo Villamor, MD, DrPH

Disclosures

Pediatr Infect Dis J. 2013;32(5):585-593. 

In This Article

Abstract and Introduction

Abstract

Background: Vitamin D deficiency (VDD) is highly prevalent among children worldwide. The effects of VDD include alterations of the immune response and increased risk of infection but little evidence exists in school-age children. We investigated the association of vitamin D status with morbidity in a prospective study of school-age children from Bogotá, Colombia.

Methods: We measured plasma 25-hydroxyvitamin D (25(OH)D) concentrations in a random sample of 475 children (mean ± standard deviation age: 8.9 ± 1.6 years) and followed them for an academic year. Caregivers were asked to record daily information on the incidence of morbidity episodes using pictorial diaries. Baseline vitamin D status was classified according to 25(OH)D concentrations as deficient (<50 nmol/L), insufficient (≥50 and <75 nmol/L) or sufficient (≥75 nmol/L). We used Poisson regression to estimate incidence rate ratios and 95% confidence intervals for days with diarrhea, vomiting, diarrhea with vomiting, cough with fever and earache or discharge with fever, comparing vitamin D-deficient with vitamin D-sufficient children. Estimates were adjusted for child's age, sex and household socioeconomic status.

Results: The prevalence of VDD was 10%; an additional 47% of children were vitamin D-insufficient. VDD was associated with increased rates of diarrhea with vomiting (adjusted incidence rate ratio: 2.05; 95% confidence interval: 1.19, 3.53) and earache/discharge with fever (adjusted incidence rate ratio: 2.36; 95% confidence interval: 1.26, 4.44). VDD was not significantly related to cough with fever.

Conclusions: These results suggest that VDD is related to increased incidence of gastrointestinal and ear infections in school-age children. The effect of correcting VDD on reducing risk of these infections needs to be tested in supplementation trials.

Introduction

Inadequate vitamin D status is highly prevalent in children worldwide, even in equatorial regions where it had not been previously suspected. In Latin America, reported prevalence of vitamin D insufficiency and deficiency among children and adolescents ranges from 28% in Costa Rica[1] to 56% in Bogotá, Colombia[2] and 62% in São Paulo, Brazil.[3] Emerging evidence suggests that the consequences of vitamin D deficiency (VDD) extend beyond its well-known effects on bone metabolism and calcium homeostasis, and also include alterations of specific arms of immunity. The immunomodulatory properties of vitamin D may influence susceptibility to infection.[4] These effects are primarily mediated through the vitamin D receptor (VDR),[5] which is expressed in many cells of the immune system, including T and B lymphocytes, neutrophils, monocytes, macrophages and dendritic cells.[6–10]

Recent epidemiologic studies indicate that low plasma vitamin D concentrations are related to increased incidence of respiratory infections, including acute lower respiratory tract infections[11–14] and respiratory syncytial virus (RSV) disease[15] in infants and children less than 5 years of age. Furthermore, vitamin D supplementation in randomized controlled trials conducted among schoolchildren resulted in reduced incidence of influenza A infection[16] and acute respiratory infection.[17] In another trial among Afghan children less than 3 years of age, vitamin D supplementation decreased the risk of pneumonia;[18] nevertheless, a larger randomized controlled trial showed no effect among infants from the same setting.[19]

Infection is a significant cause of morbidity throughout childhood.[20] Among school-age children, respiratory and gastrointestinal infections account for increased school absenteeism and parental absenteeism from work,[21] as well as a sizeable proportion of physician visits.[22,23] However, relatively little is known about the effect of vitamin D on infection-related morbidity in children more than 5 years of age. We conducted a prospective study to investigate the association between VDD and morbidity among school-age children in Bogotá, Colombia. We hypothesized that vitamin D-deficient children are at increased risk of gastrointestinal and respiratory morbidity.

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