Hello, In ROSMAP_clinical.csv (syn3191087) there is a column named; **age_first_ad_dx**. When there is an empty value, is it safe to assume the corresponding individual was never diagnosed with AD? As such, can that individual be used as control? Best regards, Gerard **edit:** I found the answer: https://www.radc.rush.edu/docs/var/detail.htm?category=Clinical+Diagnosis&subcategory=Dementia&variable=age_first_ad_dx