In our case the finding could also be confounded by high number of unknown dates and ascertainment of correct date was not possible.
Follow-up time started (baseline) at the latest of first date of ascertainment of smoking status or 365 days after ART initiation, by which time CD4+ cell counts have usually risen substantially, with corresponding declines in AIDS-related mortality [ 7, 14, 15].
The year 1985 was chosen as the start date for ascertainment because that was the year in which the MMSSP (formerly the Manitoba Maternal AFP Screening program) became a formal provincial program, providing screening on request to all residents at no charge.
Participants were deemed as living if they had a clinical encounter within 6 months of ascertainment date and did not have a documented death in either the EMR or the SSDI.
Men were excluded from this study if they reported having exposure to finasteride or dutasteride at any time prior to their CaP diagnosis, were diagnosed more than 12 months prior to the date of study ascertainment, or had ever been diagnosed with cancer at any site (except non-CaP skin cancer) other than their recently diagnosed CaP.
Women were excluded from this study if they were non-incident cases (i.e. those diagnosed more than 12 months prior to the date of study ascertainment) or had a prior diagnosis of cancer at any site except nonmelanoma skin cancer.
The ascertainment of dates of death and dates of emigration was accomplished by linkage to the Lithuanian Residents Register Servicee.
Survival time was censored at 31 December 2009 to ensure all cases had at least one year follow-up, and because this was the latest date for which death ascertainment was complete.
Whilst there are new efforts to address this problem, to date case recognition and ascertainment (Smithson et al., 2014), collection of suitable samples and difficulties in obtaining WES data from certain types of material, have hampered progress and limited numbers.
In AACES, we found a longer length of time between date of diagnosis and ascertainment among those deceased as compared to those who eventually enrolled in the study, which may partially account for the overall high proportion of deceased patients.
Ascertainment of dates of birth was all but complete (only one missing), and dates of death were identified for 98% (343/350) of the 1914 cohort and 95% (315/331) of the late 1918 (non-combat) cohort.
