Participants who were of mixed heritage but at least one-sixteenth Native American, were recruited from eight geographically contiguous reservations with a total population of about 3,000 individuals. They were recruited using a combination of a venue-based method (Kalton and Anderson, 1986; Muhib et al., 2001), and a respondent-driven procedure (Heckathorn, 1997). The venues used as recruitment sites included tribal halls, health clinics, tribal libraries, and stores on the reservations. Fliers advertising the study were placed in each venue with the phone number of the tribal recruitment coordinator. The venues were also randomly visited by the tribal recruitment coordinator who approached potential participants in order to offer information about and enrollment in the study. Individuals who elected to participate were encouraged to inform other eligible participants, particularly family members, about the study (respondent-driven procedure) (see Ehlers et al., 2004a,c).
