Table 4. Risk factors for clinical malaria in children aged 6 months to 10 years at three sites in Uganda.
| Characteristic | Walukuba | Kihihi | Nagongera | |||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Malaria incidence a (total person years) | IRR (95% CI) b | p | Malaria incidence (total person years) | IRR (95% CI) | p | Malariaincidence (total person years) | IRR (95% CI) | p | ||
| Mean age during follow–up | 6m to <3 years | 0.40 (106.0) | 1 | - | 1.58 (139.4) | 1 | - | 4.27 (110.8) | 1 | - |
| 3 to <5 years | 0.62 (93.6) | 1.59 (0.92–2.73) | 0.10 | 1.77 (104.0) | 1.10 (0.77–1.55) | 0.61 | 3.64 (110.1) | 0.86 (0.73–1.02) | 0.08 | |
| 5 to <11 years | 0.37 (223.1) | 0.90 (0.61–1.34) | 0.62 | 1.28 (352.9) | 0.79 (0.60–1.03) | 0.08 | 2.04 (328.8) | 0.48 (0.40–0.58) | <0.001 | |
| Gender | Female | 0.41 (209.8) | 1 | - | 1.24 (290.4) | 1 | - | 2.51 (248.2) | 1 | - |
| Male | 0.45 (212.8) | 1.13 (0.73–1.74) | 0.59 | 1.62 (305.9) | 1.30 (1.01–1.68) | 0.04 | 3.06 (301.5) | 1.24 (1.03–1.49) | 0.02 | |
| Wealth index, stratified by study site | 1st tertile | 0.63 (120.8) | 1 | - | 1.85 (227.5) | 1 | - | 3.03 (178.0) | 1 | - |
| 2nd tertile | 0.40 (142.4) | 0.63 (0.31–1.28) | 0.20 | 1.54 (203.7) | 0.84 (0.60–1.19) | 0.33 | 3.06 (204.3) | 1.00 (0.77–1.28) | 0.98 | |
| 3rd tertile | 0.31 (159.4) | 0.49 (0.27–0.87) | 0.02 | 0.73 (165.1) | 0.39 (0.26–0.60) | <0.001 | 2.27 (167.4) | 0.72 (0.53–0.98) | 0.04 | |
| Main floor material | Earth, sand, dung or stones | 0.52 (201.0) | 1 | - | 1.55 (486.8) | 1 | - | 2.88 (487.3) | 1 | - |
| Wood, bricks or cement | 0.35 (221.6) | 0.68 (0.40–1.17) | 0.17 | 0.91 (109.5) | 0.58 (0.39–0.86) | 0.01 | 2.26 (62.4) | 0.78 (0.49–1.24) | 0.30 | |
| Main roof material | Thatched | 0.63 (6.3) | 1 | - | 2.63 (72.0) | 1 | - | 3.14 (211.5) | 1 | - |
| Tiles or metal | 0.43 (416.3) | 0.70 (0.49–1.02) | 0.06 | 1.27 (524.4) | 0.49 (0.31–0.76) | 0.002 | 2.61 (338.1) | 0.82 (0.66–1.02) | 0.07 | |
| Main wall material | Mud | 0.56 (135.0) | 1 | - | 1.66 (453.6) | 1 | - | 2.89 (455.6) | 1 | - |
| Cement, wood or metal | 0.37 (287.7) | 0.65 (0.36–1.17) | 0.15 | 0.71 (142.7) | 0.42 (0.28–0.64) | <0.001 | 2.44 (94.1) | 0.84 (0.57–1.24) | 0.39 | |
| Eaves | Open | 0.49 (120.5) | 1 | - | 2.10 (148.9) | 1 | - | 2.98 (267.9) | 1 | - |
| Closed | 0.41 (302.2) | 0.81 (0.43–1.51) | 0.50 | 1.21 (447.4) | 0.59 (0.40–0.86) | 0.01 | 2.65 (281.7) | 0.89 (0.72–1.11) | 0.30 | |
| Airbricks | Unscreened | 0.43 (59.9) | 1 | - | 1.15 (439.1) | 1 | - | 2.66 (147.4) | 1 | - |
| Screened | 0.29 (76.7) | 0.63 (0.23–1.77) | 0.38 | 0.00 (2.1) | - | - | 1.45 (4.1) | 0.55 (0.21–1.43) | 0.22 | |
| None | 0.47 (286.1) | 1.03 (0.50–2.12) | 0.93 | 2.26 (155.2) | 1.92 (1.35–2.73) | <0.001 | 2.88 (398.1) | 1.09 (0.83–1.43) | 0.54 | |
| House type c | Traditional | 0.53 (197.2) | 1 | - | 1.63 (461.7) | 1 | - | 2.89 (455.6) | 1 | - |
| Modern d | 0.35 (225.4) | 0.80 (0.46–1.39) | 0.43 | 0.74 (134.6) | 0.61 (0.40–0.91) | 0.02 | 2.44 (94.1) | 0.90 (0.63–1.28) | 0.55 | |
aMalaria incidence per person years (new malaria episodes/person years of observation)
bIRR: Incidence rate ratio; CI: Confidence interval.
cIRR adjusted for mean age during follow up, gender and household wealth.
dCement, wood or metal wall; tiled or metal roof and closed eaves.