Distribution of enrolled participants by major recruitment sources (A) and by race (B), gender (C) and age (D). The yields from the different sources were significantly different from a hypothetical distribution of 1:1:1 (chi square P < 0.0001). Advertising yielded more participants than community outreach (P = 0.0003) or clinical facilities (P < 0.0001). Community outreach was significantly more productive than accrual from clinical facilities (P < 0.0001). * P < 0.05, ** P < 0.001.