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

Abstract

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.

Risk Factors for Severity in Children with Coronavirus Disease 2019

“…Although the mechanism of the vitamin D effect on immunity is complex, currently available data support the hypothesis that cathelicidins and defensins can reduce viral replication rates and the levels of proinflammatory cytokines. 76 Studies in small children with influenza have shown that high doses of vitamin D resulted in fast relief from symptoms, a rapid decrease in viral load, and early disease recovery. In addition, high daily doses of vitamin D have been shown to be effective in the prevention of seasonal influenza.…”

Nutritional perspectives for the prevention and mitigation of COVID-19

“… 84 , 85 A correlation between increased incidence of COVID-19 and insufficient vitamin D concentrations in patients was further supported by Zhang and Liu, 12 who confirmed that middle-aged to elderly people recently affected by COVID-19 in China had low vitamin D levels. However, Zisi et al 86 has highlighted the need to validate whether vitamin D supplementation is beneficial for COVID-19 patients, as conflicting results were noted in some studies, while Grant et al 13 suggested vitamin D supplementation as a therapeutic option for the treatment of COVID-19.…”

Pharmacotherapy in COVID-19 patients: a review of ACE2-raising drugs and their clinical safety

“…Similar to statins, Vitamin D, a steroid hormone made in the skin by the action of sunlight, may also have anti-inflammatory and immune-regulatory properties [135,136]. In COVID-19, there is currently no reports on prospective studies examining supplementation with vitamin D or its analogs and outcomes in patients but a recent study by Hastie et al [137] showed that vitamin D deficiency was associated with higher risk of SARS-CoV-2 infection; however the authors claim this was not causal.…”

“…In COVID-19, there is currently no reports on prospective studies examining supplementation with vitamin D or its analogs and outcomes in patients but a recent study by Hastie et al [137] showed that vitamin D deficiency was associated with higher risk of SARS-CoV-2 infection; however the authors claim this was not causal. Based on preclinical and clinical studies suggesting the vitamin D deficiency is associated with increased acute respiratory tract infections [136,138], further clinical trials on whether vitamin D supplementation is beneficial in preventing COVID-19 infections are pending. However, as a precautionary measure, the UK government has proactively issued a recommendation for its population to take Vitamin D supplements during the COVID-19 pandemic [139,140].…”