Study selection Study designs of evaluations included in the review All study designs excluding letters, case reports and single case studies were included in the review. Studies reported in the review included: RCTs, controlled multiple crossover, controlled nonrandomized concurrent control, controlled nonrandomized historical control, uncontrolled case series, uncontrolled retrospective case ...

Case-control studies are retrospective investigations in which a diseased group (cases) and a disease-free group (controls) are compared with the aim of uncovering risk factors that differ between the groups. Many times, cause-effect relationships between the risk factor and disease are inferred from the results. Many important risk factors have been identified through the use of a casecontrol ...

Case-control studies are used to determine if there is an association between an exposure and a specific health outcome. These studies proceed from effect (e.g. health outcome, condition, disease) to cause (exposure). Case-control studies assess whether exposure is disproportionately distributed between the cases and controls, which may indicate that the exposure is a risk factor for the health...

create a niche for M. tuberculosis (10). Our hypothesis could be refuted or corroborated in several ways, for example, by a case-control study of HIV-negative patients infected with tuberculosis. If this study refutes our hypothesis, the idea that sex hormones play a direct role in the immune response to M. tuberculosis would be supported. Such findings might also provide possibilities for drug...

Introduction: Oral Lichen Planus (OLP) is a chronic inflammatory disease of oral mucosa with unknown etiology.Many studies have suggested that increased oxidative stress, an imbalance in the antioxidant defense system maybe involved pathogenesis planus.Aim: The aim this study was to compare tissue levels Super oxide dismutase (SOD) and lipidperoxidation marker Malondialdehyde (MDA) established ...

These three articles, based upon casecontrol epidemiology, have formed the principal support for the theory that very low exposures to asbestos will in fact multiply the risk for, and thereby increase the incidence of mesothelioma. In each of these studies, one or more industrial hygiene experts, blinded to the purpose of their work, reviewed data about patients with a confirmed diagnosis of me...

• Travel and thrombosis are associated. Four case-control studies [1-4] and five cohort and randomized controlled studies [5-9] have clearly established that thrombosis is associated with travel. In the four case-control studies, 11.8% of patients with venous thromboembolism had a history of recent travel, by air or other means of transportation, compared to 6.3% of controls with an odds ratio ...

All studies were categorised according to the strength of the evidence based on the following revised classification system. Level I Evidence obtained from a systematic review of all relevant randomised controlled trials. Level II Evidence obtained from at least one properly designed randomised controlled trial. Level III.1 Evidence obtained from well designed pseudo-randomised controlled trial...