Clinical Trial Service Unit

About: Clinical Trial Service Unit is a based out in . It is known for research contribution in the topics: Population & Stroke. The organization has 428 authors who have published 1387 publications receiving 181920 citations.

Genetically Determined Levels of Circulating Cytokines and Risk of Stroke

Abstract: Background: Cytokines and growth factors have been implicated in the initiation and propagation of vascular disease. Observational studies have shown associations of their circulating levels with s...

Can dietary supplements with folic acid or vitamin B6 reduce cardiovascular risk? Design of clinical trials to test the homocysteine hypothesis of vascular disease.

Abstract: Correspondence and requests for reprints to Dr Robert Clarke, Clinical Trial Service Unit, Radcliffe Infirmary, Oxford OX2 6HE, UK. Tel: +44 1865 557241 ; fax: +44 1866 658817; e-mail: robert.clarke@ctsu.ox.ac.uk Introduction Moderately elevated levels of blood total homocysteine have been identified as a potentially important modifiable risk factor for cardiovascular disease [ 11. Many studies, conducted in various settings, have reported that patients with coronary heart disease [2-231, stroke [24-301 and peripheral vascular disease [31-361 , have higher homocysteine levels than controls. T h e initial studies were case-control (or ‘retrospective’) studies, which compared homocysteine levels in samples from cases, collected after the onset of disease, with those in controls. Weaker associations have been reported in some prospective studies in which blood was taken some years before vascular disease was diagnosed [2,3,6], and no association was reported in others [4,5]. In a meta-analysis of the published epidemiological studies of homocysteine and coronary heart disease in this issue, Danesh and Lewington estimate that the odds ratio of coronary heart disease for a 5 pmol/l higher blood total homocysteine level was 1.3 (95% CI 1.1-1.5) in prospective studies, 1.6 (95% CI 1.4-1.7) in retrospective studies with population controls, and 1.9 (95% CI 1.6-2.3) in retrospective studies with other controls. In addition, elevated homocysteine levels have been associated with an increased risk of mortality among patients with established coronary disease [37]. I t is unclear to what extent the discrepant results of different study designs are a result of random error, bias (resulting from the effects of illness on blood homocysteine levels) or incomplete adjustment for confounding factors (such as blood pressure, smoking and cholesterol). Furthermore, substantial uncertainty persists about the strength of the relationship between homocysteine and vascular disease in ageand sex-specific groups, and about the graded nature of increasing risk with increasing homocysteine levels across the distribution found in the general population. This has prompted a meta-analysis of individual participant data from all the observational studies in order to address these issues.

Esophageal cancer and body mass index: results from a prospective study of 220,000 men in China and a meta-analysis of published studies.

Abstract: Several epidemiological studies have reported on the association between body mass index (BMI) and risk of esophageal cancer, but these were mostly in Western populations where many are overweight or obese. There is little direct evidence about the relationship in China where the mean BMI is relatively low and the disease rate is high. We examined the data from a populationbased prospective study of 220,000 Chinese men aged 40–79 without a previous history of cancer (mean BMI 21.7 kg/m 2 ), which included 1,082 esophageal cancer deaths during 10 years of follow-up. Adjusted hazard ratios for death from esophageal cancer by baseline BMI category were calculated using Cox proportional hazards models. Even among men with good self-assessed health and BMI 18.5 kg/m 2 , there was a strong inverse association between BMI and death from esophageal cancer, with each 5 kg/ m 2 higher BMI associated with 25% (95%CI: 11–36%) lower esophageal cancer mortality. This inverse association persisted when analysis was restricted to men who had never smoked or when the first 5 years of follow-up were excluded. The strength of the relationship was consistent with the pooled estimate for squamous cell carcinoma of the esophagus in a meta-analysis of prospective studies (31% lower relative risk per 5 kg/m 2 higher BMI; 95% CI: 25–37%), but contrasted with that for adenocarcinoma which showed a positive association with BMI. Together, these data provide reliable evidence that in many populations low BMI is associated with an increased risk of squamous cell carcinoma of the esophagus. ' 2007 Wiley-Liss, Inc.