Biology subjects

Becerra, M. C.

Publications and source records attributed to Becerra, M. C..

4 recordsLinked to original sources

bioRxiv2018

Isoniazid preventive therapy protects against tuberculosis among household contacts of isoniazid-resistant patients.

BackgroundThe World Health Organization recommends the use of isoniazid (INH) alone or combination INH and rifapentine therapy to treat latent tuberculosis infection (LTBI) in groups at high risk of tuberculosis (TB) progression. The recent rise of INH- and multi-drug resistant (MDR) TB has complicated the choice of LTBI treatment regimen. We examine the risk of TB disease among household contacts (HHCs) who received INH after being exposed to patients with drug-sensitive, INH-resistant, or MDR tuberculosis. MethodsIn this prospective cohort study conducted Between September 2009 and August 2012 in Lima, Peru, we identified 4,500 index TB patients and measured incident TB disease in their 14,044 HHCs over a one-year follow-up period. HHCs under 19 years of age were offered INH preventive therapy (IPT). We used a Cox frailty proportional hazards model to evaluate whether the effect of IPT on incident TB disease varied by the resistance profile of the index case. We repeated the analyses in a second independent dataset. FindingsAmong 4,216 HHCs under 19 years of age, 2,106 (50%) initiated IPT at enrolment. The protective effect of INH was more extreme in HHCs exposed to drug-sensitive (Hazard Ratio [95% confidence interval]=0{middle dot}2[0{middle dot}20-0{middle dot}50]) and to MDR-TB (0{middle dot}26[0{middle dot}08-0{middle dot}77]) compared to those exposed to mono-INH-resistant (0{middle dot}80[0{middle dot}23 to 2{middle dot}79]). Among those who received at least three months of INH, effectiveness increased across all three groups (INH-sensitive:0{middle dot}20 [0{middle dot}10 to 040]; MDR:0{middle dot}16 [0 02-127]; mono-INH-resistant:0{middle dot}72 [0{middle dot}16-3{middle dot}16]). In the second independent study, TB occurred in none of the 76 HHCs who received IPT compared to 3% (8/273) of those who did not. InterpretationWe found that IPT use is associated with reduced incidence of TB disease among contacts of MDR-TB patients. This finding suggests that INH may have role in the management of MDR-LTBI. FundingNational Institutes of Health and the National Institute of Allergy and Infectious Diseases CETR (U19AI109755) and TBRU (U19AI111224)

epidemiology↗

bioRxiv2018

Vitamin D status and risk of incident tuberculosis disease: a systematic review and individual participant data meta-analysis

BackgroundFew studies have evaluated the association between pre-existing vitamin D deficiency (VDD) and incident TB. We assessed the impact of baseline vitamin D on TB risk. MethodsWe assessed the association between baseline vitamin D and incident TB in a prospective cohort of 6751 household contacts of TB patients in Peru. We also conducted a one-stage individual participant data meta-analysis searching PubMed and Embase for studies of vitamin D and TB until December 31, 2017. We included studies that assessed vitamin D before TB diagnosis. We defined VDD as 25-(OH)D <50 nmol/L, insufficiency as 50-75 nmol/L and sufficiency as >75nmol/L. We estimated the association between vitamin D and incident TB using conditional logistic regression in the Peru cohort and generalized linear mixed models in the meta-analysis. FindingsIn Peru, baseline VDD was associated with a statistically insignificant increase in incident TB (aOR 1{middle dot}70, 95% CI 0{middle dot}84-3{middle dot}46; p=0{middle dot}14). We identified seven studies for the meta-analysis and analyzed 3544 participants. Individuals with VDD and very low vitamin D (<25nmol/L) had increased TB risk (aOR 1{middle dot}48, 95% CI 1{middle dot}04-210;p=0{middle dot} 03 and aOR 2 08, 95% CI 0{middle dot}88-4{middle dot}92; p trend=002 respectively). Among HIV-positive patients, VDD and very low vitamin D conferred a 2-fold (aOR 2.18, 95% CI 1{middle dot} 22-3{middle dot}90; p=0{middle dot} 01) and 4-fold (aOR 4{middle dot}28, 95% CI 0{middle dot}85-21{middle dot}44; p trend=0{middle dot}01) increased risk of TB respectively. InterpretationOur findings suggest vitamin D predicts TB risk in a dose-dependent manner and vitamin D supplementation may play a role in TB prevention. FundingNational Institute of Health (NIH), National Institute of Allergy and Infectious Diseases (NIAID), National Institute on Drug Abuse (NIDA), National Institute of Mental Health (NIMH), International Maternal Pediatric Adolescent AIDS Clinical Trials Group (IMPAACT), Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), National Institute of Dental and Craniofacial Research (NIDCR), Boehringer-Ingelheim, Bristol-Myers Squibb, Gilead Sciences, GlaxoSmithKline, Foundation, Ujala Foundation, Wyncote Foundation, NIH - Fogarty International Center Program of International Training Grants in Epidemiology Related to AIDS, NIAID Byramjee Jeejeebhoy Medical College HIV Clinical Trials Unit, NIAIDs Baltimore-Washington-India Clinical Trials Unit, National Commission on Biotechnology, the Higher Education Commission, International Research Support Initiative Program of the Higher Education Commission Government of Pakistan, the Bill and Melinda Gates Foundation, and the NIH Fogarty International Center. Research in ContextO_ST_ABSEvidence before this studyC_ST_ABSNumerous studies have found lower serum vitamin D levels among patients with active TB disease compared to healthy controls. However, research has not clarified whether low vitamin D increases TB risk or whether TB disease leads to decreased vitamin D levels. We conducted PubMed and Medline searches for all studies available through December 31, 2017 on the association between vitamin D status and TB disease. We included the following keywords: "vitamin D," "vitamin D deficiency," "hypovitaminosis D," "25-hydroxyvitamin D," "1,25-dihydroxyvitamin D," "vitamin D2," "vitamin D3," "ergocalciferol," "cholecalciferol," and "tuberculosis." We found only seven studies had prospectively evaluated the impact of baseline vitamin D levels on risk of progression to TB disease. We report here the results of a case control study nested within a large prospective longitudinal cohort study of household contacts of TB cases and the results of an individual participant data (IPD) metaanalysis of available evidence on the association between vitamin D levels and incident TB disease. Added value of this studyWe demonstrated that low vitamin D levels predicts risk of future progression to TB disease in a dose-dependent manner. Implications of all the available evidenceThese findings suggest the possibility that vitamin D supplementation among individuals at high risk for developing TB disease might play a role in TB prevention efforts.

epidemiology↗

bioRxiv2018

RESISTANCE AT NO COST: THE TRANSMISSIBILITY AND POTENTIAL FOR DISEASE PROGRESSION OF DRUG-RESISTANT M. TUBERCULOSIS

BackgroundThe future trajectory of drug resistant tuberculosis strongly depends on the fitness costs of drug resistance mutations. Here, we measured the association of phenotypic drug resistance and the risk of TB infection and disease among household contacts (HHCs) of patients with pulmonary TB.\n\nMethodsWe evaluated 12767 HHCs of patients with drug sensitive and resistant pulmonary TB at baseline, two, six, and 12 months to ascertain infection status and to determine whether they developed tuberculosis disease. We also assessed the impact of drug resistance phenotype on the likelihood that a TB strain shared a genetic fingerprint with at least one other TB patient in the cohort.\n\nFindingsAmong 3339 TB patients for whom were DST available, 1274 (38%) had TB that was resistant to at least one drug and 478 (14*3%) had multi-drug resistant (MDR) TB, i.e. TB resistant to both INH and rifampicin. Compared to HHCs of drug sensitive TB patients, those exposed to a patient with MDR-TB had an 8% (95% CI: 4-13%) higher risk of infection by the end of follow up. We found no statistically significant difference in the relative hazard of incident TB disease among HHCs exposed to MDR-TB compared to DS-TB (Adjusted HR 1*28 [(95% CI: *9-1*83]). Patients with MDR-TB were more likely to be part of a genetic cluster than were DS-TB patients.\n\nInterpretationClinical strains of MDR M. tuberculosis are neither less transmissible than drug sensitive strains nor less likely to cause disease. (ClinicalTrials.gov number, NCT00676754)\n\nFundingNational Institutes of Health: NIH/NIAID CETR U19AI109755\n\nStatementAll authors have seen the manuscript and approved the manuscript.

epidemiology↗

bioRxiv2017

The Impact of Vitamin A and Carotenoids on the Risk of Tuberculosis Progression

BackgroundLow and deficient levels of vitamin A are common in low and middle income countries where tuberculosis burden is high. We assessed the impact of baseline levels of vitamins A and carotenoids on TB disease risk.\n\nMethods and FindingsWe conducted a case-control study nested within a longitudinal cohort of household contacts of pulmonary TB cases in Lima, Peru. We screened all contacts for TB disease at 2, 6, and 12 months after enrollment. We defined cases as HIV-negative household contacts with blood samples who developed TB disease at least 15 days after enrollment of the index patient. For each case, we randomly selected 4 controls from among contacts who did not develop TB disease, matching on gender and year of age. We used conditional logistic regression to estimate odds ratios (ORs) for incident TB disease by vitamin A and carotenoids levels, controlling for other nutritional and socioeconomic factors.\n\nAmong 6751 HIV-negative household contacts with baseline blood samples, 192 developed secondary TB disease during follow-up. We analyzed 180 cases with viable samples and 709 matched controls. After controlling for possible confounders, we found that baseline vitamin A deficiency was associated with a 10-fold increase in risk of TB disease among household contacts (aOR 10.42; 95% CI 4.01-27.05; p < 0.001). This association was dose-dependent with stepwise increases in TB disease risk with each decreasing quartile of vitamin A level. Carotenoid levels were also inversely associated with TB risk among adolescents.\n\nOur study is limited by the one year duration of follow up and by the relatively few blood samples available from household contacts under ten years of age.\n\nConclusionsVitamin A deficiency strongly predicted risk of incident TB disease among household contacts of TB patients. Vitamin A supplementation among individuals at high risk of TB may provide an effective means of preventing TB disease.

epidemiology↗