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The International Journal of... May 2008Many molecular epidemiology studies have been conducted to identify risk factors for clustering of tuberculosis (TB) cases in the population. (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Many molecular epidemiology studies have been conducted to identify risk factors for clustering of tuberculosis (TB) cases in the population.
OBJECTIVE
To estimate the impact of commonly investigated risk factors on TB clustering.
METHODS
Ten electronic databases were searched up to January 2006 along with a hand search of the International Journal of Tuberculosis and Lung Disease and bibliographies of review articles. Meta-analyses of odds ratios (ORs) for various risk factors were conducted using random effect models, stratified by TB incidence. Meta-regressions were employed to account for the heterogeneity in clustering proportions and the magnitudes of risk.
FINDINGS
The TB clustering proportion varied greatly (7.0-72.3%) among 36 studies in 17 countries. In multiple meta-regression analyses, high TB incidence, mean cluster size and conventional contact tracing were significantly associated with higher clustering. The pooled ORs (95%CIs) for low and high/intermediate TB incidence studies, using a cut off of 25/100000 per year, were 3.4 (2.7- 4.2) and 1.6 (1.3-2.1) for local-born status, 1.6 (1.5-1.7) and 1.7 (1.3-2.2) for pulmonary TB and 1.2 (1.1-1.3) and 1.3 (1.1-1.7) for smear-positive cases, respectively. Male sex, local birth, alcohol abuse and injection drug use were significantly higher risks in low TB incidence studies than in the high/intermediate ones.
INTERPRETATION
Meta-analyses yielded significant estimates of ORs for several risk factors across both levels of TB incidence. Alcohol abuse, injection drug use and homelessness--all characteristics of marginalized populations--were found to be consistently significant in populations of low TB incidence. More research is needed to better understand TB transmission dynamics in high-burden countries.
Topics: Cluster Analysis; DNA Fingerprinting; Global Health; Humans; Incidence; Mycobacterium tuberculosis; Regression Analysis; Risk Factors; Tuberculosis
PubMed: 18419882
DOI: No ID Found -
The Journal of Infectious Diseases Jul 2007Reinfection is a major contributor to tuberculosis (TB). It seems that the higher the local incidence, the higher the proportion of reinfection. (Review)
Review
BACKGROUND
Reinfection is a major contributor to tuberculosis (TB). It seems that the higher the local incidence, the higher the proportion of reinfection.
METHODS
Based on a systematic review of the literature, we established a regression model to predict the reinfection proportion from the local incidence. We then used our local data to verify the algorithm.
RESULTS
Of the 23 studies addressing reinfection in recurrent TB, 6 were population based. The reinfection proportion was correlated with the local incidence (reinfection proportion=-29.7+36.8 x log Incidence) (95% confidence interval [CI] for coefficient, 15.3-58.3; R2=0.849). The reinfection proportion in Taiwan (incidence, 62.4/100,000 people) was estimated to be 36% (95% CI, 3%-69%). Of our 49 recurrent patients, 51% had reinfection. Patients with reactivation seemed more likely to have underlying diseases and less likely to be smear positive. The relapse isolates seemed more resistant than the initial isolates.
CONCLUSIONS
The regression model could possibly predict the TB reinfection proportion from the local incidence. This algorithm is probably helpful in policy making for TB control programs. In areas where TB is endemic, reinfection might be responsible for >50% of TB cases, and aggressive surveillance to detect asymptomatic carriers could be an important strategy for controlling the disease.
Topics: DNA Fingerprinting; Forecasting; Humans; Incidence; Models, Statistical; Recurrence; Regression Analysis; Tuberculosis
PubMed: 17570116
DOI: 10.1086/518898 -
European Journal of Human Genetics :... Jun 2007As sequence analysis for BRCA1 and BRCA2 mutations is both time- and cost-intensive, current strategies often include scanning techniques to identify fragments... (Review)
Review
As sequence analysis for BRCA1 and BRCA2 mutations is both time- and cost-intensive, current strategies often include scanning techniques to identify fragments containing genetic sequence alterations. However, a systematic assessment of the diagnostic accuracy has been lacking so far. Here, we report on a systematic review to assess the internal and external validity of current scanning techniques. Inclusion criteria were: controlled design, investigators blinded, and tests suitable as a scanning tool for the whole genes BRCA1 and BRCA2. Outcome parameters were sensitivity, specificity, and positive and negative predictive values compared to direct sequencing. Out of 3816 publications, 10 studies reporting on 12 methods met our inclusion criteria. The internal and external validity of most of these studies was limited. Sensitivities were reported to be 100% for enzymatic mutation detection (EMD), multiple-dye cleavase fragment length polymorphism (MD-CFLP), fluorescence-based conformation-sensitive gel electrophoresis (F-CSGE), RNA-based sequencing, restriction endonuclease fingerprinting-single strand conformation polymorphism (REF-SSCP), stop codon (SC) assay, and denaturing high-performance liquid chromatography (DHPLC). Sensitivity was 50-96% for SSCP, 88-91% for two-dimensional gene scanning (TDGS), 76% for conformation-sensitive gel electrophoresis (CSGE), 75% for protein truncation test (PTT), and 58% for micronucleus test (MNT). Specificities close to 100% were reported, except for MNT. PTT and SC assay are only able to detect truncating mutations. Most studies were designed to introduce new experimental approaches or modifications of established methods and require further evaluation. F-CSGE, REF-SSCP, RNA-based sequencing, EMD, and MD-CFLP will need further evaluation before their use in a routine setting can be considered. SSCP, MNT, PTT, CSGE, and TDGS cannot be recommended because of their low sensitivity. DHPLC outperforms all other methods studied. However, none of the four studies evaluating DHPLC was performed on BRCA2.
Topics: Apoptosis Regulatory Proteins; BRCA1 Protein; BRCA2 Protein; Breast Neoplasms; Chromatography, High Pressure Liquid; DNA Mutational Analysis; Female; Genetic Techniques; Humans; Micronucleus Tests; Mutation; Nucleic Acid Denaturation; Polymorphism, Single-Stranded Conformational; Predictive Value of Tests; Reproducibility of Results; Sensitivity and Specificity; Sequence Analysis, RNA
PubMed: 17342152
DOI: 10.1038/sj.ejhg.5201806