Follow-up was from the date of screening to the date of death, date of embarkation, or 31 December 2007 (median 29 years, maximum 42 years).
Follow up began on the date of screening to the date of cancer incidence, date of death, date of embarkation (leaving the United Kingdom) or the censor date of 31st December 2007, whichever came first.
Person-years were calculated from date of screening to date of death, date of embarkation or the end of 2009 as appropriate.
A date of embarkation field is in the registry but we did not think this was reliable enough in relation to non-UK migration to use to adjust denominators.
Thirty two women who had never smoked had left the United Kingdom and we censored their survival time at their date of embarkation.
NOAR patients were censored for analysis at date of death, date of embarkation or 30 June 2012, whichever came first.
All patients were flagged with the Office for National Statistics and followed up from the date of symptom onset to date of death, embarkation date or 1 May 2011, whichever came first.
Follow-up was to the date of the first occurrence of the SMR1, SMR6, death, embarkation, or 31 December 2007.
Patients who no longer could be tracked because they moved out of the country (n=5; 0.004%) were censored on the date of 'embarkation.' Primary analysis consisted of investigating the association between the first definition of remission and all-cause mortality.
