BackgroundFew studies have evaluated the association between preexisting vitamin D deficiency and incident tuberculosis (TB). We assessed the impact of baseline vitamins D levels on TB disease risk.Methods and findingsWe assessed the association between baseline vitamin D and incident TB in a prospective cohort of 6,751 HIV-negative household contacts of TB patients enrolled between September 1, 2009, and August 29, 2012, in Lima, Peru. We screened for TB disease at 2, 6, and 12 months after enrollment. We defined cases as household contacts who developed TB disease at least 15 days after enrollment of the index patient. For each case, we randomly selected four controls from among contacts who did not develop TB disease, matching on gender and year of age. We also conducted a one-stage individual-participant data (IPD) meta-analysis searching PubMed and Embase to identify prospective studies of vitamin D and TB disease until June 8, 2019. We included studies that assessed vitamin D before TB diagnosis. In the primary analysis, we defined vitamin D deficiency as 25–(OH)D < 50 nmol/L, insufficiency as 50–75 nmol/L, and sufficiency as >75nmol/L. We estimated the association between baseline vitamin D status and incident TB using conditional logistic regression in the Lima cohort and generalized linear mixed models in the meta-analysis. We further defined severe vitamin D deficiency as 25–(OH)D < 25 nmol/L and performed stratified analyses by HIV status in the IPD meta-analysis. In the Lima cohort, we analyzed 180 cases and 709 matched controls. The adjusted odds ratio (aOR) for TB risk among participants with baseline vitamin D deficiency compared to sufficient vitamin D was 1.63 (95% CI 0.75–3.52; p = 0.22). We included seven published studies in the meta-analysis and analyzed 3,544 participants. In the pooled analysis, the aOR was 1.48 (95% CI 1.04–2.10; p = 0.03). The aOR for severe vitamin D deficiency was 2.05 (95% CI 0.87–4.87; p trend for decreasing 25–(OH)D levels from sufficient vitamin D to severe deficiency = 0.02). Among 1,576 HIV-positive patients, vitamin D deficiency conferred a 2-fold (aOR 2.18, 95% CI 1.22–3.90; p = 0.01) increased risk of TB, and the aOR for severe vitamin D deficiency compared to sufficient vitamin D was 4.28 (95% CI 0.85–21.45; p = 0.08). Our Lima cohort study is limited by the short duration of follow-up, and the IPD meta-analysis is limited by the number of possible confounding covariates available across all studies.ConclusionOur findings suggest vitamin D predicts TB disease risk in a dose-dependent manner and that the risk of TB disease is highest among HIV-positive individuals with severe vitamin D deficiency. Randomized control trials are needed to evaluate the possible role of vitamin D supplementation on reducing TB disease risk.

BackgroundDeficient serum vitamin D levels have been associated with incidence of tuberculosis (TB), and latent tuberculosis infection (LTBI). However, to our knowledge, no studies on vitamin D status and tuberculin skin test (TST) conversion have been published to date. The aim of this study was to estimate the associations of serum 25-hydroxyvitamin D3 (25[OH]D) status with LTBI prevalence and TST conversion in contacts of active TB in Castellon (Spain).MethodsThe study was designed in two phases: cross-sectional and case-control. From November 2009 to October 2010, contacts of 42 TB patients (36 pulmonary, and 6 extra-pulmonary) were studied in order to screen for TB. LTBI and TST conversion cases were defined following TST, clinical, analytic and radiographic examinations. Serum 25(OH)D levels were measured by electrochemiluminescence immunoassay (ECLIA) on a COBAS® 410 ROCHE® analyzer. Logistic regression models were used in the statistical analysis.ResultsThe study comprised 202 people with a participation rate of 60.1%. Only 20.3% of the participants had a sufficient serum 25(OH)D (≥ 30 ng/ml) level. In the cross-sectional phase, 50 participants had LTBI and no association between LTBI status and serum 25(OH)D was found. After 2 months, 11 out of 93 negative LTBI participants, without primary prophylaxis, presented TST conversion with initial serum 25(OH)D levels: a:19.4% (7/36): < 20 ng/ml, b:12.5% (4/32):20-29 ng/ml, and c:0%(0/25) ≥ 30 ng/ml. A sufficient serum 25(OH)D level was a protector against TST conversion a: Odds Ratio (OR) = 1.00; b: OR = 0.49 (95% confidence interval (CI) 0.07-2.66); and c: OR = 0.10 (95% CI 0.00-0.76), trends p = 0.019, adjusted for high exposure and sputum acid-fast bacilli positive index cases. The mean of serum level 25(OH)D in TST conversion cases was lower than controls,17.5 ± 5.6 ng/ml versus 25.9 ± 13.7 ng/ml (p = 0.041).ConclusionsThe results suggest that sufficient serum 25(OH)D levels protect against TST conversion.

The objective of this study was to estimate the relationship between serum vitamin D (VitD) status and tuberculosis (TB) infection conversion (TBIC), measured by the tuberculin skin test (TST) and an interferon-gamma release assay, the QuantiFERON-TB Gold In-Tube (QFT-GIT) test, in the contacts of pulmonary TB patients in Castellon (Spain) in a prospective cohort study from 2010 to 2012. Initially, the participants were negative to latent TB infection after a screening that included TST and QFT-GIT tests, and other examinations. A baseline determination of 25-hydroxyvitamin D [25(OH)D] was obtained by chemiluminescence immunoassay. After 8-10 weeks, participants were screened for a second time to determine TB infection conversion (TBIC). Poisson regression models were used in the statistical analysis. Of the 247 participants in the cohort, 198 (80·2%) were screened twice and 18 (9·1%) were TBIC cases. The means of VitD concentration in the TBIC cases and the non-cases were 20·7±11·9 and 27·2±11·4 ng/ml (P = 0·028), respectively. Adjusted for high exposure and TB sputum acid-fast bacilli (AFB)-positive index case, higher serum VitD concentration was associated with low incidence of TBIC (P trend = 0·005), and an increase of 1 ng/ml VitD concentration decreased the incidence of TBIC by 6% (relative risk 0·94, 95% confidence interval 0·90-0·99, P = 0·015). The results suggest that sufficient VitD level could be a protective factor of TBIC.

A prospective cohort study was conducted from 2009 to 2012 to assess the relationship between serum baseline 25-hydroxivytamin D (vitamin D) status and the incidence of tuberculosis (TB) among 572 contacts of 89 pulmonary TB patients in Castellon, Spain. Three new cases of pulmonary TB occurred, with an incidence density of 3.6 per 1000 person-years. Mean vitamin D status was 13.7 ng/ml for cases and 25.7 ng/ml for non-cases. Vitamin D status showed a significant inverse association with TB incidence (adjusted HR 0.88, 95%CI 0.80-0.97). This result is in line with the hypothesis that vitamin D deficiency is associated with TB incidence.

OBJECTIVE: To examine the potential association between vitamin D (VitD) deficiency and latent tuberculosis infection (LTBI) and its effect on TB infection conversion (TBIC) incidence.MATERIAL AND METHODS: We carried out a cross-sectional and prospective cohort study of nine pulmonary TB cases that occurred in 2015–2016 in five nursing homes and one mental disability institution in Castellon, Spain. QuantiFERON®-TB Gold and the tuberculin skin test were used to detect LTBI and TBIC, respectively. Serum 25-hydroxyvitamin D was measured using chemiluminescence immunoassay. Poisson regression and inverse probability weighting were used for statistical analyses.RESULTS: The study included 448 residents, 341 staff members with 48 relatives of TB cases (participation rate 82%): of these, respectively 122 (27.2%), 37 (10.9%) and 7 (14.6%) were LTBI-positive; and respectively 22 (7.7%), 10 (3.8%) and 1 (3.7%) were TBIC-positive. LTBI was not associated with VitD status. Severe VitD deficiency (SVDD; defined as VitD level < 10 ng/ml), found in 45.1% of residents, as well as VitD levels of <30 ng/ml (aRR 10.41 95% CI 1.48–73.26), were associated with increased TBIC risk (adjusted relative risk [aRR] 12.1, 95% CI 1.51–97.10), suggesting SVDD as a threshold effect. CONCLUSION: Severe VitD deficiency is a TBIC risk factor.

Background: Serum vitamin D (VitD) status is associated with active tuberculosis (TB) and TB infection conversion (TBIC). Objectives: The objective of the present study was to quantify the risks of TB (latent, conversion, disease) in accordance with VitD status and other variables among the contacts of pulmonary TB patients. Methods: From 2009 to 2012, a cohort of the contacts of pulmonary TB patients was studied to rule out and prevent TB in Castellon (Spain). The exams performed included a tuberculin skin test (TST), a QuantiFERON Gold in-tube test® (QFTGIT), blood and radiographic tests, and an initial measurement of serum VitD status. Contacts who were initially without active TB were followed up through 2015. Multinomial logistic regression (MLR) analyses were carried out. Results: From a total of 572 contacts of pulmonary TB patients with VitD status measurement, 523 completed the follow-up (participation rate 91.4%). Among them, five groups could be established: 3 new cases of pulmonary TB (0.6%), 27 cases of TBIC (5.2%), 116 cases of latent TB infection (LTBI) (22.2%), 125 uninfected TB contacts with only one TST or QFTGIT measurement (23.9%), and 252 uninfected TB contacts with two TST or QFTGIT measurements (48.2%). The comparison of these five groups revealed several significant differences, including age, whether they were foreign-born, place of residence, social class, high exposure to an index case with sputum acid-fast bacilli (AFB), and VitD status. The MLR analysis for all groups, with the group of uninfected TB contacts with two TST or QFTGIT measurements as a reference, estimated that only two of these factors were significantly associated with TB in three or more groups; these factors were VitD status and high exposure and a sputum AFB-positive index case. VitD status was a protector against pulmonary TB with a relative risk (RR) of 0.86 (95% confidence interval [CI] 0.74 -0.99) and against TBIC (R = 0.95; 95% CI 0.91 -0.99), while it was not associated with LTBI (RR = 0.99; 95% CI 0.97-1.01). Only 34.0% of the contacts had sufficient VitD levels (≥ 30 ng/mL). Conclusions: Our results suggest that a sufficient VitD level could be a protective factor against TBIC and active TB.