Question Posted 02/16/18:
To whom it may concern,

I'm having difficulty finding onset year of AD/MCI for subjects enrolled with an established diagnosis of AD or MCI at baseline. There are several variables in this regard in PTDEMOG datasheet, but it has lots of missing values. Also, there is no variable in PTDEMOG datasheet on MCI onset year of ADNI1 MCI subjects.
Are there any other sources besides PTDEMOG dataset to find this data?

Response posted 02/16/18 by Danielle:
I am not aware of any other sources of this information - we did not collect information on MCI onset in ADNI-1 (started in ADNI-GO). The information collected for AD onset or MCI onset was collected if possible, but as you noted, it is not available for all MCI or AD participants.