Among the 2174 COGA initial probands who had been selected for follow-up, 2149 had a baseline DSM-IV AUD diagnosis (American Psychiatric Association, 1994) at their first interview, of whom 512 were determined to have died and are the focus of a separate paper. Of the remainder, 28 were located but were unavailable for further evaluation because they were incarcerated or too ill to be interviewed (e.g., severe dementia), 55 refused evaluation, and 697 were interviewed an average of 21.7 (SD 3.29) years after their initial COGA interview (range 13–26 years). Outcomes for an additional 857 individuals could not be determined within the year of data collection in this study. Thus, 1292 of the 2149 (60.1%) subjects were located (i.e., had died, were interviewed, were contacted but refused, or were located but could not be interviewed). Among the 1554 COGA participants likely to be still alive and available for interview 697 (44.9%) were interviewed. Among these, 34 were abstinent the year prior to interview but had two or more alcohol problems in the five years prior to interview and who, therefore, did not fit into any of the outcome categories used in the analyses.
