Open AccessAssociation of vitamin D deficiency, season of the year, and latent tuberculosis infection among household contacts
Author(s) -
María Elvira Balcells,
Patricia García,
Camila Tiznado,
Luís Villarroel,
Natalia Scioscia,
Camila Carvajal,
Francesca Zegna-Ratá,
Mario Hernández,
Paulina Meza,
Luis González,
Carlos Peña,
Rodrigo Naves
Publication year - 2017
Publication title -
plos one
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.99
H-Index - 332
ISSN - 1932-6203
DOI - 10.1371/journal.pone.0175400
Subject(s) - vitamin d deficiency , medicine , vitamin d and neurology , tuberculosis , latent tuberculosis , mycobacterium tuberculosis , immunology , pathology
Objectives Vitamin D (VD) enhances the immune response against Mycobacterium tuberculosis in vitro , and VD deficiency has been described in patients with active tuberculosis (TB). However, the role of hypovitaminosis D in the pathogenesis of early TB infection acquisition is unclear. We aimed to evaluate the association of VD deficiency, season of the year, and latent TB infection in household contacts (HHC), given that this is a potentially modifiable condition often related to nutritional deficiencies and lack of sun exposure. Methods We prospectively enrolled new pulmonary TB cases (n = 107) and their HHC (n = 144) over a 2-year period in Santiago, Chile. We compared plasma 25-hydroxycholecalciferol (25OHD) levels and examined the influence of season, ethnic background, living conditions, and country of origin. Results Over 77% of TB cases and 62.6% of HHC had VD deficiency (<20 ng/ml). Median 25OHD concentration was significantly lower in TB cases than in HHC (11.7 vs. 18.2 ng/ml, p<0.0001). Migrants HHC had lower 25OHD levels than non-migrants (14.6 vs. 19.0 ng/ml, p = 0.026), and a trend towards a higher burden of latent TB infection (52.9% vs. 35.2%, p = 0.066). Multivariate analysis found VD deficiency in HHC was strongly associated with being sampled in winter/spring ( ad OR 25.68, 95%CI 7.35–89.7), corresponding to the seasons with lowest solar radiation exposure. Spring enrollment–compared with other seasons–was the chief risk factor for latent TB infection in HHC ( ad OR 3.14, 95%CI 1.28–7.69). Conclusions Hypovitaminosis D was highly prevalent in TB cases and also in HHC. A marked seasonality was found for both VD levels and latent TB in HHC, with winter being the season with lowest VD levels and spring the season with the highest risk of latent TB infection.