(b).
| Blood donors | n = 1305 | n = 889 | n = 1170 | n = 3364 | p value∗∗ |
|---|---|---|---|---|---|
| Age, median (range) | 30 (15–75) | 34 (17–56) | 32 (17–63) | 33 (15–75) | <0.0001 |
|
| |||||
| Gender | |||||
| Male | 920 (70.6) | 807 (90.8) | 878 (75.2) | 2605 (77.5) | <0.0001 |
| Female | 384 (29.4) | 82 (9.2) | 290 (24.8) | 756 (22.5) | |
|
| |||||
| Residence (n = 2999) | |||||
| Urban | 480 (51) | 596 (67) | 61 (5.2) | 1138 (38.0) | <0.0001 |
| Suburban | 116 (12.3) | 293 (33) | 839 (71.8) | 1248 (41.6) | |
| Rural | 345 (36.7) | — | 268 (23) | 613 (20.4) | |
|
| |||||
| Marital status (n = 2069) | |||||
| Married | 69 (56) | 507 (57) | 693 (65.6) | 1269 (61.3) | 0.0002 |
| Single∗ | 55 (44) | 382 (43) | 363 (34.4) | 800 (38.7) | |
|
| |||||
| Blood type | |||||
| A | 226 (17.4) | 109 (12.3) | 243 (20.8) | 578 (17.2) | <0.0001 |
| B | 282 (21.7) | 82 (9.2) | 211 (18.1) | 575 (17.1) | |
| AB | 27 (2.1) | 7 (0.8) | 42 (3.6) | 76 (2.3) | |
| O | 767 (58.9) | 689 (77.7) | 672 (57.5) | 2128 (63.4) | |
|
| |||||
| Rh status | |||||
| Positive | 1251 (95.9) | 875 (98.4) | 1129 (96.6) | 3255 (96.8) | 0.0033 |
| Negative | 54 (4.1) | 14 (1.6) | 40 (3.4) | 108 (3.2) | |
∗Demographics were available at 3 of the 4 study sites.
∗∗ p value is to test the overall difference in seroprevalence for each categorical variable (χ 2 test) or the median difference of the continuous variable.