Baseline data on plateau airway pressure were insufficiently reported to evaluate this variable as an effect modifier.
Regarding the location of the tumour, previous studies have not evaluated this variable as a risk factor.
In some cases, culling information was readily available; however, many studies provided no or insufficient information to evaluate this variable.
No association with duration of EBF was reported in the single previous study that evaluated this variable [ 29], even though an association was found in our cohort.
It should be pointed out, however, that the low number of grade 1 carcinomas (three cases) in this study would not allow us to evaluate this variable with any degree of confidence.
Though the other previous studies did not evaluate this variable, making it difficult for comparison, evidence has shown that health seeking behaviour of individuals are better during symptomatic illness than if there is no symptom [ 25].
The chromosome complement in a tumor sample can profoundly affect the interpretation of losses and gains within the karyotype, and conventional CGH using comparative hybridization between tumor and normal samples does not evaluate this variable.
36 In addition, though the percentage of a hospital owned by physicians has been previously associated with cherry picking, we could not evaluate how this variable influenced our outcomes of interest.
In order to further evaluate this correlation the variable EDN was divided into three parts (low, medium, high) thereby creating the independent variable EDN-group.
To obtain a single (summary) effect estimate for urinary cadmium with each outcome, we evaluated this cadmium quartile trend variable in the fully adjusted models.
Tests for trend were performed by assigning participants the median value in their quintile of exposure and evaluating this as a continuous variable.
