Table 1.
Comparison of Participating and Nonparticipating Subjects
| Variable | Participants (N = 267) | Nonparticipants (N = 233) | P* Value |
| Age (yr) Mean (SDs) | 69.18 (2.727) | 69.18 (2.832) | 0.990 |
| Sex | 0.148 | ||
| Male (%) | 157 (58.8) | 122 (52.4) | |
| Female (%) | 110 (41.2) | 111 (47.6) | |
| Education | 0.013 | ||
| Illiterate (%) | 117 (43.8) | 128 (54.9) | |
| Primary school or above (%) | 150 (56.2) | 105 (45.1) | |
| Monthly income (USD) | 0.107 | ||
| <$860 (%) | 193 (72.3) | 190 (81.5) | |
| $860~2,000 (%) | 59 (22.1) | 33 (14.2) | |
| $2,001~2,860 (%) | 12 (4.5) | 8 (3.4) | |
| >$2,860 (%) | 3 (1.1) | 2 (0.9) |
*The P values for the percentages of sex, education, and monthly income refer to X2 tests of differences between participating and nonparticipating subjects. For age, the P value refers to the t-test of differences between participating and nonparticipating subjects.