Table 1. Characteristics of the 36110 former plasma donors included in the analysis from 1985–2008, stratified by plasma donation window ≤2 years vs. >2 years.
| Characteristic | Total | Interval between dates of first and last plasma donation | P-value | |
| 0–2 years | >2 years or missing dates† | |||
| No. (%) | No. (%) | No. (%) | ||
| Overall | 36110 | 16038 | 20072 | |
| Gender | ||||
| Male | 20875 (57.8) | 9137 (57.0) | 11738 (58.5) | <0.001 |
| Female | 15235 (42.2) | 6901 (43.0) | 8334 (41.5) | |
| Estimated age at HIV infection (years) | ||||
| <18 | — | 765 (4.8) | — | — |
| 18–44 | — | 14349 (90.4) | — | |
| ≥45 | — | 767 (4.8) | — | |
| Missing | 157 | |||
| Ethnicity | ||||
| Han | 35243 (97.6) | 15831 (98.7) | 19412 (96.7) | <0.001 |
| Other | 867 (2.4) | 207 (1.3) | 660 (3.3) | |
| Marriage* | ||||
| Married/Live Together | 28921 (81.2) | 12868 (80.3) | 16053 (82.0) | <0.001 |
| Single/Divorced/Widowed | 6680 (18.8) | 3147 (19.7) | 3533 (18.0) | |
| Missing | 509 | 23 | 486 | |
| Education* | ||||
| Primary school & below | 22021 (63.0) | 10138 (63.7) | 11883 (62.5) | 0.013 |
| Middle school & above | 12908 (37.0) | 5765 (36.3) | 7143 (37.5) | |
| Missing | 1181 | 135 | 1046 | |
| Occupation* | ||||
| Farmer | 34163 (94.6) | 15511 (96.7) | 18652 (92.9) | <0.001 |
| Others | 1947 (5.4) | 527 (3.3) | 1420 (7.1) | |
| Province* | ||||
| Henan | 28644 (79.3) | 13489 (84.1) | 15155 (75.5) | <0.001 |
| Anhui | 3189 (8.8) | 1360 (8.5) | 1829 (9.1) | |
| Hubei | 1523 (4.2) | 650 (4.1) | 873 (4.3) | |
| Shanxi | 724 (2.0) | 206 (1.3) | 518 (2.6) | |
| Shandong | 198 (0.5) | 91 (0.6) | 107 (0.5) | |
| Other | 1832 (5.1) | 242 (1.5) | 1590 (7.9) | |
| Estimated year of HIV infection | ||||
| ≤1990 | — | 554 (3.5) | — | — |
| 1991 | — | 1032 (6.4) | — | |
| 1992 | — | 2649 (16.5) | — | |
| 1993 | — | 3669 (22.9) | — | |
| 1994 | — | 5174 (32.3) | — | |
| 1995 | — | 2469 (15.4) | — | |
| 1996 | — | 313 (2.0) | — | |
| ≥1997 | — | 178 (1.1) | — | |
†
N = 9922 for those with interval >2 years and N = 10150 for those with missing dates.
*Data as of when the person was identified as HIV positive.