ACONF is one of the three Aberdeen Birth Cohorts whose participants had completed tests of reading and mental ability as schoolchildren in Aberdeen, Scotland. Decades later, these children were recontacted and followed as adults. ACONF includes 12,150 individuals (6,282 males, 5,868 females) who were born between 1950-1956 and took reading and mathematics tests during primary school, when they were aged 6-12 years, as part of a study investigating learning disabilities by the University of Aberdeen in 1962-1964. Participants were recontacted in 1999 to establish the cohort and have been followed up through linkage and a postal survey in 2001-2003.