title: Both high and low serum vitamin D concentrations are associated with tuberculosis: a case-control study in Greenland.
abstract: Vitamin D deficiency has been associated with increased risk of tuberculosis (TB). Changes from a traditional to a Westernised diet among Greenlanders have resulted in reduced serum vitamin D, leading to considerations of whether preventive vitamin D supplementation should be introduced. The association between vitamin D status and TB was examined to assess the feasibility of vitamin D supplementation in Greenland. This was examined in a case-control study involving seventy-two matched pairs of TB patients (cases) and controls aged 8-74 years. Cases were diagnosed with TB during 2004-6 based on clinical findings in combination with either (1) positive Mycobacterium tuberculosis culture, (2) characteristic X-ray abnormalities together with a positive tuberculin skin test or a positive interferon-γ release assay or (3) characteristic histology. Controls were individually matched on age ( ± 5 years), sex and district. Serum 25-hydroxyvitamin D (25(OH)D) concentrations were measured and OR of TB were the outcome. Compared with individuals with 25(OH)D concentrations between 75 and 140 nmol/l, individuals with concentrations < 75 nmol/l (OR 6.5; 95% CI 1.8, 23.5) or > 140 nmol/l (OR 6.5; 95% CI 1.9, 22.2) had higher risks of active TB (P = 0.003; adjustment for alcohol and ethnicity). Supplementing individuals with low vitamin D to normalise serum 25(OH)D concentrations was estimated to result in a 29% reduction in the number of TB cases. The study indicated that vitamin D supplementation may be beneficial to individuals with insufficient vitamin D concentrations but may increase the risk of TB among individuals with normal or high concentrations.
authors.affiliation: Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark. nij@ssi.dk
authors.forename: Nina O
authors.initials: NO
authors.lastname: Nielsen
authors.forename: Turid
authors.initials: T
authors.lastname: Skifte
authors.forename: Mikael
authors.initials: M
authors.lastname: Andersson
authors.forename: Jan
authors.initials: J
authors.lastname: Wohlfahrt
authors.forename: Bolette
authors.initials: B
authors.lastname: Søborg
authors.forename: Anders
authors.initials: A
authors.lastname: Koch
authors.forename: Mads
authors.initials: M
authors.lastname: Melbye
authors.forename: Karin
authors.initials: K
authors.lastname: Ladefoged
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D002648:Child; D005260:Female; D006116:Greenland / Q000453:epidemiology; D006801:Humans; D004930:Inuit / Q000706:statistics & numerical data; D008297:Male; D008875:Middle Aged; D014397:Tuberculosis, Pulmonary / Q000097:blood* / Q000453:epidemiology / Q000208:ethnology; D014807:Vitamin D / Q000097:blood*; D055815:Young Adult
chemical_list: D014807:Vitamin D