The rationale for this approach is to create a clear graphical relationship avoiding the difficult and confounding use of a standard plot of the original 470 experimental points.
Aspirin users were excluded to select a population with lower cardiovascular risk and to determine whether celecoxib has a greater GI benefit than nsNSAIDs, without the confounding use of aspirin.
Despite these limitations, except for the risk factor "fore-stripping" and the confounding factor "use of a specific brand of milking equipment", the significant risk factors can be explained biologically.
A confounding effect of smoking, coffee, and alcohol use in combination has been noted, but other investigators suggest independence of these factors.
It is, however, possible that there may be a confounding effect between the use of telephone interviews and experience at contact tracing.
A confounding factor when using collections of experimental studies might be potential knowledge-related biases, that is, the experimental studies are not equally distributed among the genes.
Strengths of the study include: a long time series; adjustment for potentially confounding economic factors; use of a large database of ED presentations including both urban and rural populations and a conservative approach to estimating the impact of the taxation measures.
Notably, a confounding factor in using data from several of the large BC clinical trials is that each study used different, and often vague, definitions of 'postmenopausal' (Table 1) [ 1, 2, 9, 91– 91].
However, a confounding factor is the prolonged use of new hearing instruments which may explain part of the improved intelligibility with learned settings.
But the hypothesis should be evaluated in a prospective, multicentre study with protocolized ScvO2 measurements and detailed registration of potentially confounding factors, including use of fluid, vasopressors, inotropes and blood, to reduce the risk of bias.
