- Residence in the designated geographic areas selected for the study (The planned source population is all New Jersey, New York, Pennsylvania and North Central Aetna Individual Medicare members and North Central. If members identified from these states have not filled the study within three months, the source population may be expanded to include Aetna's North Central region members in Illinois and Ohio. These North Central members would include all Aetna Medicare Individual members in these areas, plus any Group Medicare members from Groups whose Plan Sponsors agree that the study may be offered to the members.)