title: Vitamin D and airway infections: a European perspective.
abstract: Vitamin D has immuno-modulatory properties, and deficient levels of circulating 25-hydroxyvitamin D (<30 nmol/l) may contribute to increased risk of infectious illnesses. This narrative review summarises data on vitamin D status in Europe and updates results of randomised controlled trials (RCTs) regarding vitamin D and airway infections such as tuberculosis (TB) and acute upper respiratory tract infection. In Europe, the prevalence of vitamin D deficiency is up to 37% in the general population and up to 80% in nursing home residents and non-European immigrants. Half of TB patients have a migration background. While results of RCTs do not support the concept of beneficial adjunctive effects of vitamin D supplements in anti-TB treatment [odds ratio (OR) = 0.86; 95% CI 0.62-1.19], the few published RCTs on the prophylaxis of TB suggest some protective vitamin D effects in individuals with deficient circulating 25-hydroxyvitamin D levels. Regarding acute respiratory tract infection, RCTs indicate a significant risk reduction by vitamin D supplements [OR = 0.65; 95% confidence interval (CI) 0.50-0.85]. There is evidence that daily administration is more effective than high-dose bolus administration [OR = 0.48 (95% CI 0.30-0.77) vs. OR = 0.87 (95% CI 0.67-1.14)] and that individuals with deficient or insufficient (30-50 nmol/l) circulating 25-hydroxyvitamin D levels benefit most. Several vitamin D effects on innate immunity may explain these protective effects. In summary, there is possible evidence from RCTs for protective vitamin D effects on TB and likely evidence for protective effects on acute airway infection. Since vitamin D deficiency is prevalent in Europe, especially in institutionalised individuals and non-European immigrants, daily oral vitamin D intake, e.g. 1000 international units, is an inexpensive measure to ensure adequate vitamin D status in individuals at risk.
authors.affiliation: Department of Thoracic and Cardiovascular Surgery, NRW Heart and Diabetes Centre, Clinic for Thoracic and Cardiovascular Surgery, Ruhr University of Bochum, Georgstraße 11, 32545, Bad Oeynhausen, Germany. azittermann@hdz-nrw.de.
authors.forename: Armin
authors.initials: A
authors.lastname: Zittermann
authors.affiliation: Department of Endocrinology and Metabolism, Medical University of Graz, Graz, Austria.
authors.forename: Stefan
authors.initials: S
authors.lastname: Pilz
authors.affiliation: Synlab MVZ Gauting, Institute of Microbiology and Laboratory Medicine, WHO Supranational Reference Laboratory of Tuberculosis, Gauting, Germany.
authors.forename: Harald
authors.initials: H
authors.lastname: Hoffmann
authors.affiliation: Synlab Academy for Continuing Medical Education, Mannheim und Synlab Services GmbH, Augsburg, Germany.|Clinical Institute for Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Graz, Austria.|Department of Medicine V (Nephrology, Hypertension, Rheumatology, Endocrinology, Diabetology) Mannheim Faculty of Medicine, University of Heidelberg, Heidelberg, Germany.
authors.forename: Winfried
authors.initials: W
authors.lastname: März
mesh_terms: D019587:Dietary Supplements; D005060:Europe / Q000453:epidemiology; D006801:Humans; D015995:Prevalence; D016032:Randomized Controlled Trials as Topic; D012141:Respiratory Tract Infections / Q000097:blood* / Q000175:diagnosis / Q000517:prevention & control; D012307:Risk Factors; D014376:Tuberculosis / Q000097:blood* / Q000175:diagnosis / Q000517:prevention & control; D014807:Vitamin D / Q000008:administration & dosage / Q000097:blood*; D014808:Vitamin D Deficiency / Q000097:blood* / Q000453:epidemiology / Q000517:prevention & control
chemical_list: D014807:Vitamin D
keywords: 25-hydroxyvitamin D; Acute airway infection; Immune defence; Infection; Tuberculosis; Vitamin D