The role of vitamin D in children with recurrent tonsillopharyngitis

Is There any Association between Vitamin D Deficiency and Recurrent Tonsillopharyngitis? An Updated Systematic Review

Introduction: It has been theorized that vitamin D deficiency is directly associated with the occurrence of recurrent tonsillopharyngitis. The purpose of this study was to investigate the potential association between vitamin D levels and recurrent tonsillopharyngitis. Methods:We searched the databases of PubMed, Scopus and Cochrane Central Register of Controlled Trials (CENTRAL) until the 15th of August 2023. Original articles of any study design assessing the correlation between recurrent tonsillopharyngitis and vitamin D levels in both pediatric and adult patients were considered. Serum 25-hydroxyvitamin D level was the measured outcome. Quality assessment was carried out by using the Newcastle-Ottawa scale (NOS) for observational studies. Results:Eleven observational studies with a total of 2 503 participants were included in this systematic review. The qualitative synthesis revealed a possible association between recurrent tonsillopharyngitis and vitamin D deficiency. All studies, except one study, demonstrated a statistically significant association between the two conditions. As per our quality appraisal, all papers were deemed to be of moderate or good quality. Conclusion:This study shows a potential association between vitamin D deficiency and the development of recurrent tonsillopharyngitis. Future studies should not only investigate this association in a more comprehensive manner but also assess the prevention potential of vitamin D supplementation on tonsillopharyngitis pathogenesis.

Impact of vitamin D in children with chronic tonsillitis (immunohistochemical study of CD68 polarisation and proinflammatory cytokines estimation)

Inflammatory processes are increasingly attributed to macrophage polarization. Proinflammatory macrophages promote T helper (Th) 1 response, tissue repair, and Th2 responses. Detection of macrophages in tissue sections is facilitated by CD68. Our study is focused on the expression of CD68 and the estimation of proinflammatory cytokines in children's patients with chronic tonsillitis secondary to vitamin D supplementation. This hospital-based Randomized prospective case-control study was conducted on 80 children with chronic tonsillitis associated with vitamin D deficiency where (40 received vitamin D 50,000 IU weekly for 3-6 months and 40 received 5 ml distilled water as placebo). The serum 25-hydroxyvitamin D [25(OH)D] was measured using an Enzyme-linked immunosorbent assay on all included children. Different histological and immunohistochemical studies for the detection of CD68 were done. There was a significantly lower serum level of 25(OH)D in the placebo group versus the vitamin D group (P < 0.001). The levels of pro-inflammatory cytokines, TNFα, and IL-2 significantly increased in the placebo group as compared to the vitamin D group (P < 0.001). The increased level of IL-4 and IL-10 in the placebo group as compared to the vitamin D group was insignificant (P = 0.32, 0.82) respectively. Vitamin D supplementation alleviated the deleterious effect of chronic tonsillitis on the histological structure of the tonsil. Tonsillar tissues of the children in the control and vitamin D groups demonstrated a highly statistically significantly lower number of CD68 immunoexpressing cells compared with those in the placebo group (P < 0.001). Low vitamin D may play a role in chronic tonsillitis. Vitamin D supplementation could help reduce the occurrence of chronic tonsillitis in susceptible children.

Evaluation of Serum 25(OH) Vitamin D as a Risk Factor in Adult Recurrent Tonsillitis

Background Studies have reported that the rate of upper respiratory tract infections in children and adults is inversely related to serum vitamin D levels and supplementation with vitamin D reduces the incidence of this infection. This study aimed to examine if vitamin D serum levels were a risk factor for recurrent tonsillitis among adult patients. Methods Retrospective comparative analysis was carried out on 100 patients diagnosed with recurrent tonsillitis with 100 age- and sex-matched individuals as controls between June 2016 and May 2022. Tonsillar size was assessed based on Brodsky grading system. Serum levels of 25-hydroxy (25(OH)) vitamin D, total calcium, iron, hemoglobin, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) were analyzed. Results There was a statistically significant low vitamin D levels in tonsil size grades III+IV compared to grade I+II (p <0.001) among cases. There was a significantly lower serum value for 25(OH) vitamin D in the cases as compared to the control group (p <0.001). A high percentage (68%) of cases had vitamin D deficiency (<20 ng/mL) and this was statistically significant (p <0.001). There were statistically significant higher values of CRP and ESR among cases compared to the control group (p <0.001). At a cut off (≤21.2), serum vitamin D levels achieved 78% sensitivity, 65% specificity (p <0.001) to differentiate cases from controls. Following logistic regression analysis, the level of vitamin D was the only significant risk factor. Conclusion Findings from our study also suggest an association between recurrent tonsillitis among our adult cohorts and low serum 25(OH) vitamin D levels. Therefore, we opine that serum vitamin D levels should be considered in the management of adult patients with tonsillitis.

The effect of nutritional status on post-operative outcomes in pediatric otolaryngology-head and neck surgery

INTRODUCTION

Nutritional status can affect surgical patients in terms of stress response, healing time, and outcomes. Several abnormalities are known to have a high prevalence in the general population such as vitamin D deficiency (VDD) and subclinical hypothyroidism. We hypothesized that there will be elevated rates of nutritional deficiencies in preoperative patients which may adversely affect postoperative outcomes following pediatric otolaryngology surgery.

METHODS

IRB approval was obtained for a cross-sectional cohort study. Consecutive patients underwent nutritional evaluation when being scheduled for surgery including TSH, albumin and vitamin D. Demographic data, supplementation, and early complication rates were collected.

RESULTS

125 patients were included in the final cohort with adequate demographic distribution. Based on anthropometric data, 12% of our cohort was found to be undernourished, and 40% of our cohort with elevated BMI. However, there was no relationship found between Z-scores and complications. VDD was noted in 83/125 (66.4%) patients. Our cohort had increased rates of VDD in patients with elevated BMI and African American ethnicity. Thyroid hormone abnormalities were present in 12 patients. Mean serum albumin level was 4.29 in our cohort all within normal range. We did find increased risk of postoperative complications in patients with previously diagnosed comorbidities. (p=0.006).

CONCLUSION

There is no current recommendation or consensus for nutritional assessment in preoperative pediatric patients. Our study did not show statistically significant correlation with z-scores, low vitamin D levels with supplementation, albumin, or TSH to postoperative complications. However, our patient cohort had higher than average rates of VDD compared to the many studies of the general pediatric population and significant negative correlation between vitamin D levels and z-scores. By early preoperative identification of VDD and supplementation with calciferol, we found no significant difference in complication rates in patients based on their initial vitamin D status. We suggest screening preoperative patients using z-score calculations and vitamin D levels based on individual patient risk factors including atrisk patient populations such as African American children, and obese children.

The Association Between Vitamin D Deficiency and Recurrent Tonsillitis: A Systematic Review and Meta-analysis

OBJECTIVES

The role of vitamin D deficiency has been linked with recurrent upper respiratory tract infections, but its impact on the frequency of tonsillitis is not yet fully understood. The objective of this study is to determine the association between vitamin D deficiency and recurrent tonsillitis based on current literature.

DATA SOURCE

A systematic review was performed following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. Data were collected from online medical databases (PubMed, MEDLINE, EMBASE, and Cochrane Collaboration Registry of Controlled Trials).

REVIEW METHODS

All studies addressing the association of vitamin D deficiency and recurrent tonsillitis prior to March 2019. The data were collected in different phases: screening review using search words and controlled vocabularies followed by detailed review of screened articles based on inclusion and exclusion criteria, then a full review that included screening the references of selected articles.

RESULTS

Fifty-three studies were potentially eligible; of these, 4 publications met the inclusion criteria and were included in the quantitative synthesis. There was a statistically significant reduction of vitamin D levels in patients with recurrent tonsillitis as compared to healthy controls (mean difference, -10.71; 95% CI, -19.12 to -2.31; P = .01). The odds of vitamin D insufficiency were significantly higher in patients with recurrent tonsillitis as compared to the control group (odds ratio, 4.37; 95% CI, 2.78-6.88; P < .001).

CONCLUSION

Vitamin D deficiency was present in patients with recurrent tonsillitis and might be associated with an increase in the risk of recurrent tonsillitis. There is a need to explore these findings via clinical trials based on large populations.

The association between vitamin D status and infectious diseases of the respiratory system in infancy and childhood

PURPOSE

Respiratory tract infections (RTIs) are a major cause of illness worldwide and the most common cause of hospitalization for pneumonia and bronchiolitis. These two diseases are the leading causes of morbidity and mortality among children under 5 years of age. Vitamin D is believed to have immunomodulatory effects on the innate and adaptive immune systems by modulating the expression of antimicrobial peptides, like cathelicidin, in response to both viral and bacterial stimuli. The aim of this review is to summarize the more recently published data with regard to potential associations of 25-hydroxyvitamin D [25(OH)D] with infectious respiratory tract diseases of childhood and the possible health benefits from vitamin D supplementation.

METHODS

The literature search was conducted by using the PubMed, Scopus, and Google Scholar databases, with the following keywords: vitamin D, respiratory tract infection, tuberculosis, influenza, infancy, and childhood.

RESULTS

Several studies have identified links between inadequate 25(OH)D concentrations and the development of upper or lower respiratory tract infections in infants and young children. Some of them also suggest that intervention with vitamin D supplements could decrease both child morbidity and mortality from such causes.

CONCLUSIONS

Most studies agree in that decreased vitamin D concentrations are prevalent among most infants and children with RTIs. Also, normal to high-serum 25(OH)D appears to have some beneficial influence on the incidence and severity of some, but not all, types of these infections. However, studies with vitamin D supplementation revealed conflicting results as to whether supplementation may be of benefit, and at what doses.

Involvement of Vitamin D in Chronic Infections of the Waldeyer`s Ring in the School Aged Child

Chronic infections of the Waldeyer`s lymphatic ring constitute a frequent pathology in school age, one of the pathogenic mechanisms involving low levels of vitamin D. In this study, we analyzed integrated the clinico-epidemiological aspects, the risk factors and the serum level of vitamin D for 51 school aged children who presented chronic inflammation in various levels of the Waldeyer`s ring. Most inflammations were present in females patients (80.4%), from the urban areas (66.6%), being localized in palatine tonsils (64.7%), in patients with deficient prophylaxis of hypovitaminosis D (68.6%) and low serum levels of vitamin D (72.5%). The results highlight the importance of maintaining a normal status of vitamin D, especially in recurrent infectious context.

Are Vitamin D Levels Associated With Risk of Deep Neck Infection?

Deep neck infection (DNI) refers to infections in spaces created by superficial and deep cervical fascia around the muscles and organs in the neck. Vitamin D is highly important for an effective immune system. Vitamin D receptors (VDR) have been identified in immune system cells, and particularly in T and B lymphocytes, macrophages, and dendritic cells. Vitamin D deficiency is thought to result in impaired immune response, decreased leukocyte chemotaxis, and an increased disposition to infection. The purpose of this study was to investigate whether vitamin D deficiency is an underlying occult factor in the development of DNI. Sixty-five patients aged 6 to 90, diagnosed with DNI, and 70 healthy age- and sex-compatible cases were included in the study. Serum levels of calcium, phosphorus, parathyroid hormone, and 25-hydroxy vitamin D (25(OH)D) were determined in each case. 25-hydroxy vitamin D levels above 20 ng/mL were regarded as normal, 12 to 20 ng/mL as insufficient, 5 to 12 ng/mL as deficient, and less than 5 ng/mL as severely deficient. Mean serum 25(OH)D levels were 10.4 (6.2) ng/mL in the patient group and 15.5 (6.4) ng/mL in the control group (P < .01). This difference was statistically significant (P < .01). Vitamin D was within normal limits in 9.2% (n = 6) of cases in the study group, insufficient in 29.2% (n = 19), deficient in 35.3% (n = 23), and severely deficient in 26.2% (n = 17). The equivalent values in the control group were 21.4% (n = 15), 48.5% (n = 34), 30% (n = 21), and 0% (n = 0). Serum 25(OH)D levels were significantly lower in patients with DNI compared to the healthy cases; 25(OH)D levels may be a factor in the development of DNI.

Cross-Sectional Evaluation of Plasma Vitamin D Levels in a Large Cohort of Italian Patients with Pediatric Autoimmune Neuropsychiatric Disorders Associated with Streptococcal Infections

BACKGROUND

Pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections (PANDAS) are immune-mediated diseases characterized by obsessive-compulsive symptoms and/or tics triggered by group A Streptococcus infections. Despite the well-known action of 25-hydroxyvitamin D [25(OH)D] on different conditions driven by systemic inflammation, there are no data about the 25(OH)D status in patients with PANDAS.

AIMS

To evaluate plasma 25(OH)D levels in a large cohort of children and adolescents with PANDAS and comparing the results with healthy controls.

METHODS

We have evaluated plasma 25(OH)D levels in 179 Italian patients with PANDAS (49 females, 130 males, mean age at diagnosis: 101.4 ± 30.1 months) and in an age-, gender-, and body mass index-matched control group of 224 healthy subjects.

RESULTS

Patients with PANDAS have shown more frequently reduced 25(OH)D levels (<30 ng/mL) in comparison with controls (94.6% vs. 82.5%, p = 0.0007). Patients with PANDAS had also lower levels of 25(OH)D than controls (20.4 ± 6.9 ng/mL vs. 24.8 ± 7.3 ng/mL, p < 0.0001). This difference was observed during both winter (13.7 ± 3.25 ng/mL vs. 21.4 ± 5.9 ng/mL, p < 0.0001) and summer (21.8 ± 6.5 ng/mL vs. 32.5 ± 8.7 ng/mL, p < 0.0001). Notably, serum 25(OH)D levels correlated with both number of streptococcal (strep) infections before diagnosis of PANDAS (p < 0.005) and with infection recurrence (p < 0.005).

CONCLUSIONS

PANDAS patients have reduced 25(OH)D levels, which appear related to streptococcal infections and the probability of recurrence. Further long-term studies with higher number of patients are needed to investigate and confirm this relationship.

Clinical Management of Pediatric Acute-Onset Neuropsychiatric Syndrome: Part III-Treatment and Prevention of Infections

Objectives: Pediatric acute-onset neuropsychiatric syndrome (PANS) and its subset, pediatric autoimmune neuropsychiatric disorder associated with streptococcal infection (PANDAS), are emerging autoimmune encephalopathies of childhood. Management guidelines are needed. This article, from the PANS/PANDAS Consortium, presents a consensus management guideline for the infection components. Accompanying papers from the Consortium discuss psychiatric and immunomodulatory management. Methods: Literature was reviewed and integrated with the clinical experience of the authors to provide a set of practical guidelines. This article was submitted to all members of the PANS/PANDAS Consortium, and their additional comments were added. Results: The relationships between PANS and infections are reviewed. An approach to the retrospective diagnosis of group A streptococcal infection for an operational definition of PANDAS is proposed. An initial course of anti-streptococcal treatment is proposed for all newly diagnosed PANS cases. Chronic secondary antimicrobial prophylaxis is suggested for children with PANDAS who have severe neuropsychiatric symptoms or recurrent group A Streptococcus-associated exacerbations. Guidelines for children with non-streptococcal PANS include vigilance for streptococcal pharyngitis or dermatitis in the patient and close contacts. All patients with PANS or PANDAS should also be closely monitored for other intercurrent infections, including sinusitis and influenza. Intercurrent infections should be diagnosed and treated promptly according to current standard guidelines. A guideline for the assessment of infection at initial onset or during neuropsychiatric exacerbations is also presented. Standard immunizations and attention to vitamin D are encouraged. Data indicating limited utility of adenotonsillectomy and probiotics are presented. Conclusion: A working guideline for the management of infection issues in PANS and PANDAS, based on literature and expert opinion, is provided.

Evaluation of vitamin D levels in children with primary epistaxis

OBJECTIVE

This study aimed to investigate whether there is a relationship between 25-hydroxy vitamin D [25(OH)D 3] values and incidences of primary epistaxis among children.

METHODS

A total of 42 cases and 55 matched controls were included in our study. The study group and control group were well matched for age and gender. Age, gender, activated partial thromboplastin time (APTT) with reference to the international normalized ratio (INR), prothrombin time (PT), and 25(OH)D 3, parathormone (PTH), alkaline phosphatase (ALP), calcium (Ca), magnesium (Mg), and phosphorus (P) values were recorded for each participant.

RESULTS

Serum 25(OH) D values were found to be statistically significantly (P = 0.03) lower in children with primary epistaxis than in the healthy control group. Our study also revealed that 25(OH) D values were considerably (P < 0.001) lower in the group with primary epistaxis and upper respiratory tract infections (RTI) than in the group with primary epistaxis without upper RTI. Univariate logistic regression analyses demonstrated that 25(OH)D 3 < 20 ng/ml [odds ratio (OR) 1.117, 95% confidence interval (CI) (1.019-1.225); P = 0.019] and serum albumin level [OR 3.499, 95% CI (1072-11,426); P = 0.038] ratio were significantly related to primary epistaxis. Furthermore, multivariate logistic regression analyses revealed that 25(OH)D 3 < 20 ng/ml [OR 1.141, 95% CI (1047-1242); P = 0.003] and serum albumin level [OR 3.340, 95% CI (1068-10,446); P = 0.038] ratio were significantly related to primary epistaxis.

CONCLUSIONS

Many studies have revealed that vitamin D is a preventive and therapeutic agent for inflammation and infection, thereby providing benefits for children with primary epistaxis. In line with this, our study suggested that a patient's vitamin D status could also be important for the prevention of childhood primary epistaxis, although further studies are required to validate our findings.

Vitamin D and respiratory tract infections in childhood

BACKGROUND

Respiratory tract infections (RTIs) remain among of the most important causes of morbidity and mortality among children. Several studies have associated vitamin D deficiency with an increased risk of RTIs, and vitamin D supplementation has been proposed as a possible preventive measure against RTIs in children. The main aim of this review is to summarize the current evidence from the literature about the link between vitamin D and RTIs in children.

DISCUSSION

Several recent studies have shown that vitamin D has different immunomodulatory properties associated with the risk of RTIs in childhood. In this regard, it is very important to understand the definition of deficiency and insufficiency of vitamin D and when and how to treat this condition. Unfortunately, there is no consensus, although a level of at least 10 ng/mL 25-hydroxycholecalciferol (25[OH]D) is thought to be necessary to promote bone mineralization and calcium homeostasis, and a concentration between 20 ng/mL and 50 ng/mL is considered adequate to provide an immunomodulatory effect. Available data support a role for vitamin D deficiency in the risk of pediatric tuberculosis, recurrent acute otitis media, and severe bronchiolitis, whereas further studies are needed to confirm an association in children with recurrent pharyngotonsillitis, acute rhinosinusitis and community-acquired pneumonia.

CONCLUSIONS

Maintenance of adequate vitamin D status may be an effective and inexpensive prophylactic method against some RTIs, but the supplementation regimen has not been clearly defined. Further clinical trials are needed to determine the 25(OH)D concentrations associated with an increased risk of RTIs and optimal vitamin D supplementation regimen according to the type of RTI while also taking into consideration vitamin D receptor polymorphisms.

Serum vitamin D levels in children with recurrent tonsillopharyngitis

OBJECTIVE

In this study, we aimed to compare vitamin D levels of children with recurrent tonsillopharingitis and healthy controls, and investigate the relationship between sociodemographic characteristics and serum vitamin D levels.

METHODS

Children with recurrent tonsillopharingitis and healthy controls aged between 2, and 12 years who consulted to the outpatient clinics of Zeynep Kamil Maternity and Children's Diseases Training and Research Hospital from January to October 2012 were included in this study. Serum 25 (OH) vitamin D levels were studied by tandem mass spectroscopy (tandem ms) method. Risk factors which might be associated with vitamin D levels were questioned. Ethical aproval was obtained from the Ethics Committee of Zeynep Kamil Maternity and Children's Diseases Training and Research Hospital and informed consent from the parents of the children.

RESULTS

A total of 147 children; 74 (50.3%) patients and 73 (49.7%) controls were included in our study. Age, gender and demographic characteristics did not differ significantly between the two groups. Vitamin D levels in patients with recurrent tonsillopharingitis and controls were 19.7±8.7 ng/ml and 23.6±9.2 ng/ml, respectively (p<0.01). Although duration of vitamin D usage was shorter in children with recurrent tonsillopharingitis, this difference was not statistically significant (p>0.05).

CONCLUSION

Vitamin D levels in children with ≥7 recurrent episodes of tonsillophargitis within the preceeding year were significantly lower compared to the control group. We believe that serum vitamin D levels should be checked in children with recurrent tonsillopharingitis and deficiencies should be treated.

Association between cord blood 25-hydroxyvitamin D concentrations and respiratory tract infections in the first 6 months of age in a Korean population: a birth cohort study (COCOA)

PURPOSE

Previous studies suggest that the concentration of 25-hydroxyvitamin D [25(OH)D] in cord blood may show an inverse association with respiratory tract infections (RTI) during childhood. The aim of the present study was to examine the influence of 25(OH)D concentrations in cord blood on infant RTI in a Korean birth cohort.

METHODS

The levels of 25(OH)D in cord blood obtained from 525 Korean newborns in the prospective COhort for Childhood Origin of Asthma and allergic diseases were examined. The primary outcome variable of interest was the prevalence of RTI at 6-month follow-up, as diagnosed by pediatricians and pediatric allergy and pulmonology specialists. RTI included acute nasopharyngitis, rhinosinusitis, otitis media, croup, tracheobronchitis, bronchiolitis, and pneumonia.

RESULTS

The median concentration of 25(OH)D in cord blood was 32.0 nmol/L (interquartile range, 21.4 to 53.2). One hundred and eighty neonates (34.3%) showed 25(OH)D concentrations less than 25.0 nmol/L, 292 (55.6%) showed 25(OH)D concentrations of 25.0-74.9 nmol/L, and 53 (10.1%) showed concentrations of ≥75.0 nmol/L. Adjusting for the season of birth, multivitamin intake during pregnancy, and exposure to passive smoking during pregnancy, 25(OH)D concentrations showed an inverse association with the risk of acquiring acute nasopharyngitis by 6 months of age (P for trend=0.0004).

CONCLUSION

The results show that 89.9% of healthy newborns in Korea are born with vitamin D insufficiency or deficiency (55.6% and 34.3%, respectively). Cord blood vitamin D insufficiency or deficiency in healthy neonates is associated with an increased risk of acute nasopharyngitis by 6 months of age. More time spent outdoors and more intensified vitamin D supplementation for pregnant women may be needed to prevent the onset of acute nasopharyngitis in infants.

1,25(OH)₂D₃ and specific IgE levels in children with recurrent tonsillitis, and allergic rhinitis

OBJECTIVES

We investigated 1,25-dihydroxyvitamin D3 [1,25(OH)₂D₃] and specific immunoglobulin E (IgE) levels in children with recurrent tonsillitis (RT) plus allergic rhinitis (AR).

METHODS

Thirty children with RT+AR were included in the study group, and 30 healthy children comprised the control group. AR-related symptoms were determined using a symptom scale. 1,25(OH)₂D₃ and specific IgE measurements were made in both groups.

RESULTS

The 1,25(OH)₂D₃ value was significantly lower in the RT+AR group than in the control group. Specific IgE (mixed) panels were in normal limits in both groups; whereas specific IgE (mixed) grass pollen panel value of RT+AT group was significantly higher than that of the control group. Higher nasal itching, nasal obstruction, and concha edema scores were related to significantly higher specific IgE values for the (mixed) grass pollen panel, whereas higher sneeze scores were related to higher specific IgE values for the (mixed) pediatric panel.

CONCLUSIONS

Children with grass pollen allergy may not be exposed to sufficient sunlight. With reduced 1,25(OH)₂D₃, T helper cells may increase, and allergic response also increases. As allergic events increased, these children did not go outside and thus lacked sun exposure. This vicious cycle must be broken, and children with RT+AR should have sunlight exposure to increase 1,25(OH)₂D₃ levels.

Vitamin D supplementation and risk of respiratory tract infections: a meta-analysis of randomized controlled trials

BACKGROUND

It is well-documented that serum levels of 25-hydroxyvitamin D (25-OHD) are inversely associated with the risk of respiratory tract infections (RTIs). However, whether or not vitamin D supplementation prevents RTIs remains inconclusive. The aim of this study was to evaluate the role of vitamin D supplementation in preventing RTIs in healthy populations by performing a meta-analysis of randomized controlled trials (RCTs).

METHODS

RCTs regarding the association between vitamin D supplementation and the risk of RTIs were identified by searching PubMed, Embase, and Cochrane databases through January 2013. Reference lists of retrieved articles were also reviewed. Either a fixed-effects or, in the presence of heterogeneity, a random-effects model was used to calculate the pooled preventive effects.

RESULTS

Seven RCTs involving 4827 participants were included in this meta-analysis. The pooled relative risk (RR) for subjects administered with vitamin D compared with control groups was 0.98 (95% confidence interval 0.93-1.03, p = 0.45). Meta-regression analyses showed almost no impact on the RR of age, vitamin D dosing regimen, and length of follow-up. Omission of any single trial had little impact on the pooled risk estimates. No evidence of publication bias was observed.

CONCLUSIONS

Our findings do not support the routine use of vitamin D supplementation for RTI prevention in healthy populations. Larger studies are needed to investigate the effects of vitamin D supplementation on RTI prevention in various populations and to further clarify the influences of age, vitamin D dosing regimen, baseline levels of vitamin D, and study length.

Role of Vitamin D in Children with Respiratory Tract Infection

It has recently been shown that vitamin D (VitD) plays an important role in host defences, inflammation and immunity. We reviewed PubMed and selected all of the studies published over the last 15 years concerning VitD deficiency and VitD supplementation in children with respiratory tract infections. Our analysis showed that VitD seems to be very important because of its part in the complexity of the immune system. However, there are few pediatric studies and most have various limitations. First of all, the literature mainly refers to studies concerning the prevalence of VitD insufficiency and deficiency in specific pathologies. Secondly, it is extremely difficult to identify a common specific range of normal, insufficient and deficient VitD levels. Thirdly, the available studies of VitD supplementation often combined VitD with the use of other micronutrients, thus obscuring the role of VitD itself. Finally, different doses have been used for VitD supplementation. These observations clearly highlight the fact that further studies are needed to evaluate the impact of VitD deficiency and insufficiency in terms of the epidemiology and outcomes of pediatric respiratory tract infection, and whether VitD supplementation favours a positive outcome.