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Exposed Subjects (exposed + subject)

Distribution by Scientific Domains
Medical Sciences100%

Selected Abstracts

Replication of the Scandinavian Simvastatin Survival Study using a primary care medical record database prompted exploration of a new method to address unmeasured confounding

PHARMACOEPIDEMIOLOGY AND DRUG SAFETY, Issue 7 2008
Mark G. Weiner M.D.
Abstract Purpose To examine whether identifiable study characteristics and/or analytic methods used determine observational study validity, as assessed by replicating randomized controlled trials using observational data. Methods A cohort from the United Kingdom General Practice Research Database (GPRD) was used to replicate the Scandinavian Simvastatin Survival Study RCT, which investigated statin treatment of hypercholesterolemic subjects with coronary heart disease. All aspects of the RCT except randomization were replicated to the extent possible in the GPRD study, which included 2,871 Unexposed and 1,280 statin-treated Exposed subjects. Results Overall mortality [adjusted hazard ratio 0.71 (0.53,0.96)] and myocardial infarction [adjusted HR 0.79 (0.61,1.02)] decreased in the GPRD study similar to the RCT. Coronary revascularization increased two-fold in the GPRD study, whereas it decreased significantly in the RCT [0.63 (0.54,0.74)]. This latter disparity prompted use of a new methodology to adjust for unmeasured confounding, which yielded an adjusted HR [1.0 (0.75,1.33)] more comparable to the RCT. Conclusions This study provides additional evidence that a replicated GPRD observational study can yield results reasonably similar to a RCT. More important, it provides preliminary evidence suggesting that a new analytic methodology may adjust for unmeasured confounding, the major limitation to research using observational data. Copyright © 2008 John Wiley & Sons, Ltd. [source]

Confounders and confusion: Dealing with cancer cases of occupational origin,

AMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 10 2010
Paolo Crosignani MD
Abstract Background The recognition of occupational cancers is often hampered by confusion between the individual determinants of the disease and effects at the group level. Methods Here we propose an approach, based on the evaluation of the attributable risk at the group level, that provides quantitative estimates of the roles of multiple causes in individuals affected of cancer within a population exposed to occupational risk. Results The estimate of individual probability can be easily obtained computing the attributable risk. This can be often achieved by using the existing information available in the literature. Conclusions Dismissing the occupation as a cause of a cancer in an exposed subject on the sole basis of potential confounding is erroneous and should be withdrawn from medical practice. Am. J. Ind. Med. 53:1002,1005, 2010. © 2010 Wiley-Liss, Inc. [source]

HLA DRB1*15-DPB1*05 haplotype: a susceptible gene marker for isocyanate-induced occupational asthma?

ALLERGY, Issue 7 2006
S.-H. Kim
Background:, There has been no study for evaluating the associations of human leukocyte antigen (HLA) class I and II alleles with toluene diisocyanate (TDI)-induced asthma in an Asian population. Objective:, The aim of this study was to investigate a susceptible or protective marker of HLA class I and II alleles in TDI-induced asthma. Methods:, Fifty-five patients with TDI-induced asthma patients (group I) showing positive responses on TDI bronchoprovocation test, 47 asymptomatic exposed subjects (group II) and 95 unexposed healthy nonatopic controls (group III) were enrolled in our study. HLA class I and II genotyping was done by the direct DNA sequencing method. Results:, The allelic frequency of C*09 (15.5%) was significantly higher in group I than in group III (6.8%, P = 0.019), but this statistical significance disappeared after correction was made for multiple comparisons. On two-locus and three-locus haplotype analysis, the allelic frequency of HLA DRB1*15-DPB1*05 in group I (10.6%) was significantly higher than that of group II (0%, P = 0.001) and group III (2.5%, P = 0.003). The allelic frequencies of HLA A*02-DRB1*15, A*02-DQB1*06, B*62-C*09 and A*02-DRB1*15-DQB1*06 were significantly higher in group I (8.5%, 10.3%, 8.2% and 6.8%, respectively) than those allelic frequencies of group III (1.3%, P = 0.002; 1.6%, P = 0.001; 0.6%, P < 0.0001; 0%, P < 0.0001, respectively). The allelic frequencies of HLA DQB1*06-DPB1*05 and DRB1*15-DQB1*06-DPB1*05 were significantly higher in group I (16.0% and 10.5%) than those in group II (2.5%, P = 0.001; 0%, P = 0.001), while the frequencies of DRB1*09-DPB1*05 and DRB1*09-DQB1*0303-DPB1*05 were significantly lower in group I (0% and 0%) than those of group II (7.4%, P = 0.004; 7.5%, P = 0.004). These differences remained statistically significant even after the correction for multiple comparisons. Conclusions:, The HLA haplotype DRB1*15-DPB1*05 can be a susceptibility gene marker for the development of TDI-induced asthma among the exposed workers in the Korean population. [source]

Factors associated with cancer distress in the Asbestos Post-Exposure Survey (APEXS),

AMERICAN JOURNAL OF INDUSTRIAL MEDICINE, Issue 4 2009
Marion Maurel MSc
Abstract Objectives CT-scan screening programs for lung cancer detection have been proposed in high-risk subjects, and more recently in former asbestos-exposed subjects. However, to date no data are available on psychological impact of such programs. The aim of this study is to examine the risk factors of psychological distress at baseline of a CT-scan screening program among asbestos-exposed subjects. Methods The Asbestos Post-Exposure Survey (APEXS) was carried out in France between October 2003 and December 2005 in order to screen asbestos-related diseases by CT-scan. Volunteers underwent self-administered questionnaires including an asbestos exposure assessment and, for a large sub-sample, a validated psychological distress scale. Non-exposed subjects were used as reference group. Results At baseline, a significant higher level of distress was observed in exposed subjects (n,=,3,122) relative to the reference group (n,=,486) after adjustment on age, sex, and tobacco status. This distress is associated independently with the self-perception of (i) intensity of asbestos exposure and (ii) the risk of current or future disease related to the asbestos exposure. The perception of the cancer risk related to asbestos seems to play a fundamental role in this psychological distress. Conclusion In this study, asbestos-exposed subjects experienced a higher significant cancer distress than previously described in literature. These findings may be of potential public health importance. First, the impact of such occupational exposures on quality of life of patients who suffer from cancer related to these exposures has to be appraised. Secondly, the assessment of psychological impact of CT-scan screening programs among asbestos-exposed subjects is also required. Am. J. Ind. Med. 52:288,296, 2009. © 2009 Wiley-Liss, Inc. [source]