Vitamin C supplementation for prevention and treatment of pneumonia
BACKGROUND: According to the Global Burden of Disease Study 2015, lower respiratory tract infection is the leading cause of infectious disease death, and the fifth most common cause of death overall. Vitamin C has a role in modulating resistance to infectious agents, therefore vitamin C supplementation may be important in preventing and treating pneumonia. OBJECTIVES: To assess the impact of vitamin C supplementation to prevent and treat pneumonia in children and adults. SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase, PubMed, CINAHL, LILACS, Web of Science, and two trials registers to 4 March 2020. We also checked references to identify additional studies. We did not apply any publication status or language filters. SELECTION CRITERIA: We included randomised controlled trials (RCTs) and quasi‐RCTs (studies using allocation methods that are not random, e.g. date of birth, medical record number) assessing the role of vitamin C supplementation in the prevention and treatment of pneumonia in children and adults compared to control or placebo. DATA COLLECTION AND ANALYSIS: We used standard methodological procedures expected by Cochrane. MAIN RESULTS: We included seven studies in the review and identified two ongoing studies. The seven included studies involved a total of 2774 participants; five studies were RCTs and two were quasi‐RCTs. The included studies were conducted in high‐income countries (UK, USA and Chile) and lower‐middle‐income countries (Bangladesh and Pakistan). Four studies were conducted in hospital inpatient settings, two in schools, and one in a military training centre. Three studies included children under five years of age, two school‐aged children, one adult participants, and one older participants aged 60 to 90 years. Two studies assessed the effect of vitamin C supplementation for pneumonia prevention; four studies assessed the effect of vitamin C supplementation as an adjunct to pneumonia treatment; and one study assessed the role of vitamin C for both prevention and treatment of ...