| Variable | Laboratory Exam | Total | P Value |
|---|
| Participant | Non-participant |
|---|
| Total | 3810 (38.4%) | 6100(61.6%) | | |
| Gender |
| Male | 1766 (46.4%) | 3155 (51.7%) | 4921 | < 0.0001 |
| Female | 2044 (53.6%) | 2945 (48.3%) | 4989 |
| Age group |
| 20–29 | 566 (14.9%) | 1397 (22.9%) | 1963 | < 0.0001 |
| 30–39 | 691 (18.2%) | 1334 (21.8%) | 2025 |
| 40–49 | 853 (22.4%) | 1196 (19.6%) | 2049 |
| 50–59 | 863 (22.7%)( | 1106 (18.1%) | 1969 |
| 60–69 | 834 (21.9%) | 1073 (17.6%) | 1907 |
| Marital status |
| Married | 3321 (87.2%) | 5109 (83.6%) | 8430 | < 0.0001 |
| Single | 295 (7.7%) | 759 (12.4%) | 1054 |
| Widowed/Divorced | 192 (5.0%) | 243 (4.0%) | 435 |
| Insurance |
| Insured | 3585 (95.4%) | 5676 (93.9%) | 9261 | 0.001 |
| Not insured | 171 (4.6%) | 366 (6.1%) | 537 |
| Job-status |
| Employed | 1379 (36.6%) | 2547 (42.3%) | 3926 | < 0.0001 |
| Unemployed | 1585 (42.1%) | 2240 (37.2%) | 3825 |
| Housewife | 802 (21.3%) | 1237 (20.5%) | 2039 |
| Education |
| Primary school and less | 1118 (29.5%) | 1469 (24.2%) | 2587 | < 0.0001 |
| High school | 1136 (30.3%) | 1666 (27.4%) | 2802 |
| Diploma& Graduate diploma | 1027 (27.1%) | 1905 (31.3%) | 2932 |
| BSc | 431 (11.4%) | 860 (14.1%) | 1291 |
| MSc. and Doctorate | 73 (1.9%) | 181 (3.0%) | 254 |
