Since then, 267 iCJD cases have been ascertained, following human growth hormone (hGH) injection, dura mater grafts, corneal transplants, neurosurgery, gonadotropin administration, and stereotactic EEG[4].
One principle of classical epidemiologic study design is that the distribution of risk factors of interest in controls should be the same as the distribution in the population from which cases have been ascertained [13].
In their theoretical study entitled "Occurrence of cancer at multiple sites: Metastasis versus multigenesis?" and submitted to Biology Direct, Zhang et al. propose that de novo initiation of cancer in multiple sites may actually account for those clinical cases in which metastasis to "unusual" sites has been ascertained.
We have assumed a discovery panel of 1,000 individuals from the same population from which the analysis cohort has been ascertained which may not always be the case.
And a preliminary review of cancer registry data from North Carolina and Florida, states known to have had an influx of retirees, indicated that only two additional cases would have been ascertained for present analyses.
Some studies report families that included fragile X affected males who were diagnosed before testing females with POI and thus it is difficult to be certain that the index POI case would have been ascertained independently; these cases may therefore increase the prior odds of finding a premutation.
Three cases of unilateral CLJ have been ascertained in Vorderwald × Montbéliarde cattle in 2009 2010 [ 13] and further six cases were reported by farmers in the following years.
We consider the case of TE insertions that have been ascertained from a single haploid reference genome sequence.
By sampling the controls from the birth cohorts, we are assuming that the controls had they developed cancer, would have been ascertained as cases in the study, and that no controls leave the risk set due to death.
