Balcells María Elvira, García Patricia, Tiznado Camila, Villarroel Luis, Scioscia Natalia, Carvajal Camila, Zegna-Ratá Francesca, Hernández Mariluz, Meza Paulina, González Luis F, Peña Carlos, Naves Rodrigo
Departamento de Enfermedades Infecciosas del Adulto, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.
Departamento de Laboratorios Clínicos, Escuela de Medicina, Pontificia Universidad Católica de Chile, Santiago, Chile.
PLoS One. 2017 Apr 12;12(4):e0175400. doi: 10.1371/journal.pone.0175400. eCollection 2017.
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.
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.
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 (adOR 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 (adOR 3.14, 95%CI 1.28-7.69).
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.
维生素D（VD）在体外可增强针对结核分枝杆菌的免疫反应，且活动性结核病（TB）患者中存在VD缺乏的情况。然而，维生素D缺乏在早期结核感染发病机制中的作用尚不清楚。鉴于VD缺乏是一种通常与营养缺乏和日照不足相关的潜在可改变状况，我们旨在评估VD缺乏、一年中的季节与家庭接触者（HHC）潜伏性结核感染之间的关联。
在智利圣地亚哥，我们在两年时间里前瞻性纳入了新的肺结核病例（n = 107）及其HHC（n = 144）。我们比较了血浆25-羟胆钙化醇（25OHD）水平，并考察了季节、种族背景、生活条件和原籍国的影响。
超过77%的结核病例和62.6%的HHC存在VD缺乏（<20 ng/ml）。结核病例的25OHD浓度中位数显著低于HHC（11.7对18.2 ng/ml，p<0.0001）。移民HHC的25OHD水平低于非移民（14.6对19.0 ng/ml，p = 0.026），且潜伏性结核感染负担有升高趋势（52.9%对35.2%，p = 0.066）。多因素分析发现，HHC中的VD缺乏与在冬季/春季采样密切相关（调整后比值比25.68，95%置信区间7.35 - 89.7），这两个季节的日照辐射最低。与其他季节相比，春季纳入是HHC潜伏性结核感染的主要危险因素（调整后比值比3.14，95%置信区间1.28 - 7.69）。
维生素D缺乏在结核病例和HHC中都非常普遍。在HHC中，VD水平和潜伏性结核都存在明显的季节性，冬季是VD水平最低的季节，春季是潜伏性结核感染风险最高的季节。
