|  |  |  | Univariate | Multivariate | ||||
---|---|---|---|---|---|---|---|---|---|
Characteristic | Â | Malaria infections (n) | Person-years at risk | Observed incidence PPY | Rate ratio (95% CI) | P value | Adjusted incidence b PPY (95% CI) | Rate ratio (95% CI) | P value |
Age (months) | 6-11 | 64 | 17 | 3.7 (2.7-5.0) | 2.2 (1.6-3.0) | <0.0001 | 2.1 (1.5-2.9) | 1.0 (0.8-1.4) | 0.84 |
 | 12+ | 1845 | 891 | 1.7 (1.6-1.8) | 1.0 |  | 2.0 (1.8-2.3) | 1.0 |  |
Sex | Female | 905 | 433 | 1.7 (1.6-1.9) | 1.0 (0.9-1.1) | 0.96 | Â | Â | Â |
 | Male | 1004 | 471 | 1.7 (1.6-1.9) | 1.0 |  |  |  |  |
Baseline Plasmodium infection | Positive | 948 | 329 | 2.4 (2.2-2.7) | 1.7 (1.5-2.0) | <0.0001 | 2.7 (2.2-3.3) | 1.7 (1.5-1.9) | <0.0001 |
Negative | 960 | 573 | 1.4 (1.3-1.5) | 1.0 | Â | 1.6 (1.3-2.0) | 1.0 | Â | |
Bed net use | ITN | 1710 | 864 | 1.6 (1.5-1.7) | 0.4 (0.3-0.5) | <0.0001 | 1.7 (1.5-2.1) | 0.7 (0.5-0.8) | <0.0001 |
 | UTN | 92 | 17 | 4.9 (4.1-5.9) | 1.1 (0.8-1.5) | 0.53 | 2.0 (1.6-2.6) | 0.8 (0.6-1.0) | 0.06 |
 | No bed net | 86 | 15 | 4.4 (3.5-5.7) | 1.0 |  | 2.6 (2.0-3.3) | 1.0 |  |
Wealth index | Poorest | 725 | 290 | 2.1 (1.9-2.3) | 1.5 (1.3-1.8) | <0.0001 | 2.3 (1.9-2.8) | 1.3 (1.1-1.5) | 0.0008 |
 | Middle | 647 | 296 | 1.8 (1.6-2.0) | 1.3 (1.1-1.6) | 0.001 | 2.2 (1.8-2.7) | 1.2 (1.1-1.5) | 0.01 |
 | Least poor | 495 | 309 | 1.4 (1.2-1.6) | 1.0 |  | 1.8 (1.4-2.2) | 1.0 |  |
Caregiver completed primary | Yes | 239 | 164 | 1.2 (0.9-1.4) | 0.6 (0.5-0.8) | <0.0001 | 1.9 (1.5-2.4) | 0.8 (0.7-1.0) | 0.02 |
No | 1628 | 730 | 1.9 (1.7-2.0) | 1.0 | Â | 2.3 (1.9-2.8) | 1.0 | Â | |
Altitude | Lowest | 680 | 300 | 1.9 (1.7-2.1) | 1.4 (1.2-1.7) | 0.0001 | 2.4 (1.9-2.9) | 1.5 (1.3-1.8) | <0.0001 |
 | Middle | 727 | 294 | 2.1 (1.9-2.4) | 1.6 (1.3-1.9) | <0.0001 | 2.4 (2.0-2.9) | 1.5 (1.3-1.8) | <0.0001 |
 | Highest | 497 | 307 | 1.3 (1.2-1.5) | 1.0 |  | 1. (1.3-2.0) | 1.0 |  |
Number of ITNs <300Â m | Lowest | 586 | 249 | 2.0 (1.8-2.3) | 1.7 (1.4-2.1) | <0.0001 | 2.1 (1.7-2.6) | 1.1 (0.9-1.4) | 0.39 |
Middle | 737 | 313 | 2.1 (1.9-2.3) | 1.7 (1.5-2.1) | <0.0001 | 2.2 (1.8-2.7) | 1.2 (0.9-1.4) | 0.17 | |
 | Highest | 389 | 272 | 1.2 (1.0-1.4) | 1.0 |  | 1.9 (1.5-2.4) | 1.0 |  |
IDW malaria prevalence | Lowest | 474 | 294 | 1.3 (1.1-1.5) | 0.6 (0.5-0.7) | <0.0001 | 1.7 (1.3-2.1) | 0.7 (0.5-0.8) | 0.0002 |
Middle | 610 | 304 | 1.7 (1.5-1.9) | 0.8 (0.6-0.9) | 0.0003 | 2.2 (1.7-2.7) | 0.9 (0.7-1.0) | 0.04 | |
 | Highest | 820 | 302 | 2.3 (2.1-2.5) | 1.0 |  | 2.5 (2.1-3.1) | 1.0 |  |
Season | Apr-June | 844 | 178 | 4.1 (3.8-4.4) | 2.3 (2.0-2.7) | <0.0001 | 4.6 (3.9-5.5) | 2.3 (2.0-2.6) | <0.0001 |
 | July-Dec | 556 | 486 | 0.9 (0.8-1.0) | 0.5 (0.4-0.6) | <0.0001 | 1.0 (0.8-1.2) | 0.5 (0.4-0.6) | <0.0001 |
 | Jan-Mar | 509 | 241 | 1.8 (1.6-2.0) | 1.0 |  | 2.0 (1.6-2.5) | 1.0 |  |