Comparison Bias and Dilution Effect in Occupational Cohort Studies

Parodi, Stefano; Gennaro, Valerio; Ceppi, Marcello; Cocco, Pierluigi

doi:10.1179/oeh.2007.13.2.143

Cited by 13 publications

(9 citation statements)

References 20 publications

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“…[5][6][7][8] The method used could result in an underestimation of the true association because of a regression dilution bias. 53 However, the described prevalence of prehypertension corresponds with previous reports. 8,54 The definition of secondary end points could be a point of criticism.…”

Section: Limitationssupporting

confidence: 89%

Subclinical Coronary Atherosclerosis Predicts Cardiovascular Risk in Different Stages of Hypertension

Erbel¹,

Lehmann²,

Möhlenkamp³

et al. 2012

Hypertension

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Abstract-Prehypertension is a frequent condition and has been demonstrated to increase cardiovascular risk. However, the association with coronary atherosclerosis as part of target organ damage is not well understood. We investigated the cross-sectional relationship and longitudinal outcome between blood pressure categories and coronary artery calcification (CAC), quantified by electron beam computed tomography, in 4181 participants from the population-based Heinz Nixdorf Recall Study cohort. At baseline, we observed a continuous increase in calcium scores with increasing blood pressure categories. During a median follow-up period of 7.18 years, 115 primary end points (2.8%; fatal and nonfatal myocardial infarction) and 152 secondary end points (3.6%; stroke and coronary revascularization) occurred. We observed a continuous increase in age-and risk factor-adjusted secondary endpoints (hazard ratios [95% CI]) with increasing blood pressure categories (referent: normotension) in men: prehypertension, 1.80 (0.53-6.13); stage 1 hypertension, 2.27 (0.66 -7.81); and stage 2 hypertension, 4.10 (1.27-13.24) and in women: prehypertension, 1.13 (0.34 -3.74); stage 1 hypertension, 2.14 (0.67-6.85); and stage 2 hypertension, 3.33 (1.24 -8.90), respectively, but not in primary endpoints. Cumulative event rates were determined by blood pressure categories and the CAC. In prehypertension, the adjusted hazard ratios for all of the events were, for CAC 1 to 99, Pϭ0.13); 100 to 399, Pϭ0.03); and Ն400, Pϭ0.0002). Risk of myocardial infarction and stroke in hypertension but also in prehypertension depends on the degree of CAC. This marker of target-organ damage might be included, when lifestyle modification and pharmacotherapeutic effects in prehypertensive individuals are tested to avoid exposure to risk and increase benefit.

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Section: Limitationssupporting

confidence: 89%

Subclinical Coronary Atherosclerosis Predicts Cardiovascular Risk in Different Stages of Hypertension

Erbel¹,

Lehmann²,

Möhlenkamp³

et al. 2012

Hypertension

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“…Usually glass and glass product, basic iron and steel, and basic precious and non-ferrous metals industries were composed of large factories, and it is thought that the proportion of workers exposed to dusts in these industries is lower than that of cast metals or cement, lime, plaster and plaster product industries. These situations might have led to risk dilution and moved the association towards null 26. In addition, each worker was assigned to only one occupation during the study period, and we did not consider job change or modifications to exposure circumstances.…”

Section: Discussionmentioning

confidence: 99%

The risk of hospitalisation for infectious pneumonia in mineral dust exposed industries: Table 1

Koh

Moon

Jeongyoun³

et al. 2010

Occup Environ Med

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“…The committee noted the potential for dilution of the risk estimate when effect estimates are calculated for “ever exposed” in studies with large numbers of individuals with low levels of exposure (e.g., based on average or cumulative exposure measures) (NRC 2006). Other examples of this type of low sensitivity can be found in studies of lung cancer and asbestos (Marsh et al, 2001), cause-specific mortality in a polyvinylchloride manufacturing cohort and a lead smelting cohort (Parodi et al, 2007), and pregnancy outcomes in relation to formaldehyde exposure among nursing personnel in surgical departments or sterilization units in general hospitals (Hemminki et al, 1982; Hemminki et al, 1985). …”

Section: Examples Of Study Sensitivitymentioning

confidence: 99%

Study sensitivity: Evaluating the ability to detect effects in systematic reviews of chemical exposures

Cooper

Lunn

Ågerstrand

et al. 2016

Environment International

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A critical step in systematic reviews of potential health hazards is the structured evaluation of the strengths and weaknesses of the included studies; risk of bias is a term often used to represent this process, specifically with respect to the evaluation of systematic errors that can lead to inaccurate (biased) results (i.e. focusing on internal validity). Systematic review methods developed in the clinical medicine arena have been adapted for use in evaluating environmental health hazards; this expansion raises questions about the scope of risk of bias tools and the extent to which they capture the elements that can affect the interpretation of results from environmental and occupational epidemiology studies and in vivo animal toxicology studies, (the studies typically available for assessment of risk of chemicals). One such element, described here as “sensitivity”, is a measure of the ability of a study to detect a true effect or hazard. This concept is similar to the concept of the sensitivity of an assay; an insensitive study may fail to show a difference that truly exists, leading to a false conclusion of no effect. Factors relating to study sensitivity should be evaluated in a systematic manner with the same rigor as the evaluation of other elements within a risk of bias framework. We discuss the importance of this component for the interpretation of individual studies, examine approaches proposed or in use to address it, and describe how it relates to other evaluation components. The evaluation domains contained within a risk of bias tool can include, or can be modified to include, some features relating to study sensitivity; the explicit inclusion of these sensitivity criteria with the same rigor and at the same stage of study evaluation as other bias-related criteria can improve the evaluation process. In some cases, these and other features may be better addressed through a separate sensitivity domain. The combined evaluation of risk of bias and sensitivity can be used to identify the most informative studies, to evaluate the confidence of the findings from individual studies and to identify those study elements that may help to explain heterogeneity across the body of literature.

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Comparison Bias and Dilution Effect in Occupational Cohort Studies

Cited by 13 publications

References 20 publications

Subclinical Coronary Atherosclerosis Predicts Cardiovascular Risk in Different Stages of Hypertension

Subclinical Coronary Atherosclerosis Predicts Cardiovascular Risk in Different Stages of Hypertension

The risk of hospitalisation for infectious pneumonia in mineral dust exposed industries: Table 1

Study sensitivity: Evaluating the ability to detect effects in systematic reviews of chemical exposures

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