Table 2 Incidence rate and hazard ratios for Plasmodium vivax episodes according to exposure status
N episodes | Person-years of follow-up | Rate (episodes/100-PY) (95 % CI) | Univariable IRR (95 % CI) | P value | Multivariable IRR (95 % CI) | P value | |
|---|---|---|---|---|---|---|---|
Gender | |||||||
Female | 279 | 802 | 34.8 (31.0–39.1) | 1 | 0.151 | 1 | 0.204 |
Male | 377 | 998 | 37.8 (34.2–41.8) | 1.2 (0.9–1.5) | 1.2 (0.9–1.5) | ||
Age (years) | |||||||
0–10 | 194 | 451 | 43.0 (37.3–49.5) | 1 | 1 | ||
10–20 | 143 | 436 | 32.8 (27.8–38.6) | 0.7 (0.6–1.0) | 0.059 | 0.7 (0.5–0.9) | 0.038 |
20–40 | 163 | 429 | 38.0 (32.6–44.3) | 0.9 (0.7–1.3) | 0.709 | 1.0 (0.7–1.3) | 0.954 |
40–60 | 114 | 328 | 34.7 (28.9–41.7) | 0.9 (0.6–1.2) | 0.461 | 0.9 (0.6–1.3) | 0.524 |
≥60 | 42 | 153 | 27.3 (20.2–36.9) | 0.7 (0.5–1.2) | 0.195 | 0.8 (0.5–1.2) | 0.229 |
Socio-economic status | |||||||
Lowest quintile | 258 | 702 | 36.7 (32.5–41.5) | 1.0 (0.8–1.2) | 0.798 | 0.9 (0.7–1.1) | 0.422 |
2nd–4th quintiles | 284 | 707 | 40.2 (35.8–45.1) | 1 | 1 | ||
Highest quintile | 114 | 320 | 35.6 (29.6–42.7) | 1.0 (0.7–1.3) | 0.825 | 0.9 (0.7–1.2) | |
Season | |||||||
Rainy | 238 | 750 | 31.7 (27.9–36.0) | 1 | 0.007 | 1 | <0.001 |
Dry | 418 | 1049 | 39.9 (36.2–43.9) | 1.2 (1.1–1.5) | 1.4 (1.1–1.6) | ||
Use of ITN | |||||||
No | 362 | 857 | 42.3 (38.1–46.8) | 1 | 0.199 | 1 | 0.001 |
Yes | 294 | 943 | 31.1 (27.8–35.0) | 0.9 (0.7–1.1) | 0.7 (0.6–0.8) | ||
IRS in last 6 months | |||||||
No | 149 | 530 | 28.1 (23.9–33.0) | 1 | 0.015 | 1 | 0.002 |
Yes | 507 | 1200 | 42.3 (38.7–46.1) | 1.4 (1.1–1.8) | 1.4 (1.1–1.8) | ||