Table 2.
Bivariate analysis of association between malaria risk (cases/controls) and various demographic, social and environmental variables in Kipsamoite and Kapsisiywa, Kenya, March–September 2004
| Potential risk factors | No. cases (n = 488) |
No. controls (n = 980) |
Crude odds ratio (95% CI) |
P |
|---|---|---|---|---|
| Socio-demographics | ||||
| Female Household Head Education | ||||
| None | 78 (16) | 155 (16) | 1.85 (1.09, 3.13) | 0.02 |
| Primary/some secondary | 386 (79) | 737 (75) | 1.92 (1.20, 3.07) | 0.006 |
| Completed Secondary + | 22 (5) | 84 (9) | 1 | |
| Household Wealth Index | ||||
| First quartile (poorest) | 123 (25) | 244(25) | 0.85 (0.62, 1.16) | 0.31 |
| Second quartile | 146 (26) | 253 (30) | 0.95 (0.70, 1.30) | 0.75 |
| Third quartile | 115 (24) | 240 (24) | 1.14 (0.85, 1.54) | 0.37 |
| Fourth quartile | 104 (21) | 243 (25) | 1 | |
| People sleeping in room | ||||
| <3 | 168(35) | 309 (31) | 1 | |
| 3–5 | 271 (45) | 571 (48) | 0.87 (0.69, 1.11) | 0.26 |
| >5 | 49 (20) | 100 (20) | 0.90 (0.61, 1.31) | 0.60 |
| Prevention activities | ||||
| Malaria prophylaxis | 4 (1) | 10 (1) | 0.82 (0.25, 2.56) | 0.71 |
| Mosquito coils | 10 (2) | 28 (3) | 0.71 (0.34, 1.48) | 0.36 |
| Bednet use | 15 (3) | 37 (4) | 0.81 (0.44, 1.49) | 0.49 |
| Clearing of bushes | 167 (34) | 398 (38) | 0.84 (0.64, 1.09) | 0.17 |
| Burning herbs at night | 55 (11) | 95 (9) | 1.12 (0.63, 1.99) | 0.69 |
| Travel/residential history | ||||
| Overnight travel 7–21 days prior | 21 (4) | 20 (2) | 2.16 (1.16, 4.02) | 0.02 |
| Immigrated from outside study | 22 (5) | 36 (4) | 1.24 (0.72, 2.13) | 0.44 |
| Agricultural and animal husbandry activities | ||||
| Channelled swamp water | 50 (10) | 44 (4) | 2.43 (1.59, 3.70) | <0.001 |
| Animals sleeping in compound | ||||
| Insecticide treated cattle | 254 (52) | 509 (52) | 1.00 (0.81, 1.25) | 0.97 |
| Insecticide free cattle | 84 (17) | 131 (13) | 1.35 (1.00, 1.82) | 0.05 |
| Goats | 43 (9) | 48 (5) | 1.88 (1.23, 2.88) | 0.003 |
| Dogs | 252 (52) | 435 (44) | 1.34 (1.08, 1.66) | 0.01 |
| House construction | ||||
| Metal roof | 284 (58) | 483 (49) | 1.43 (1.15, 1.78) | 0.001 |
| Mud walls | 430 (88) | 867 (88) | 0.97 (0.69, 1.35) | 0.84 |
| Absence of ceiling | 409 (84) | 771 (79) | 1.40 (1.05, 1.87) | 0.02 |
| Open eaves | 387 (79) | 795 (81) | 0.89 (0.68, 1.17) | 0.41 |
| Uncovered windows | 52 (11) | 119 (12) | 1.06 (0.74, 1.51) | 0.76 |
| Separate kitchen | 129 (74) | 356 (64) | 1.59 (1.25, 2.02) | 0.001 |
| Surrounding environment | ||||
| Livestock holding area <100 m | 206 (42) | 374 (38) | 1.18 (0.95,1.48) | 0.14 |
| House on flat land | 121 (25) | 179 (18) | 1.47 (1.13, 1.91) | 0.004 |
| Location at bottom of hill | 52 (11) | 85 (9) | 1.26 (0.87, 1.81) | 0.22 |
| Elevation (quartiles) | ||||
| < 1932 m | 110(23) | 260 (27) | 0.95 (0.69, 1.30) | 0.74 |
| 1932–1947 m | 114 (23) | 247 (25) | 1.03 (0.76, 1.41) | 0.84 |
| 1947–1983 m | 151 (31) | 220 (22) | 1.53 (1.13, 2.08) | 0.06 |
| > 1983 m | 113 (23) | 253 (26) | 1 | |
| Distance from forest | ||||
| < 250 m | 33 (7) | 40 (4) | 1.77 (1.10, 2.85) | 0.02 |
| 250–500 m | 37 (8) | 50 (5) | 1.58 (1.02, 2.47) | 0.04 |
| 500–1000 m | 55 (11) | 113 (12) | 1.02 (0.71, 1.45) | 0.82 |
| > 1000 m | 363 (74) | 777 (79) | 1 | |
| Distance from swamp | ||||
| < 250 m | 166 (34) | 263 (27) | 1.36 (0.94, 1.98) | 0.10 |
| 250–500 m | 198 (41) | 421 (43) | 1.02 (0.71, 1.45) | 0.93 |
| 500–1000 m | 68 (14) | 175 (18) | 0.84 (0.55, 1.28) | 0.42 |
| > 1000 m | 56 (11) | 121 (12) | 1 | |
| Distance from clinics (quartiles) | ||||
| 1190 m | 115 (23) | 253 (26) | 0.78 (0.57, 1.06) | 0.11 |
| 1190–2081 m | 125 (26) | 241 (24) | 0.89 (0.66, 1.20) | 0.44 |
| 2081–2711 m | 112 (23) | 253 (26) | 0.76 (0.56, 1.03) | 0.08 |
| >2711 m | 136 (28) | 233 (24) | 1 | |
| Distance from Stream | ||||
| < 250 m | 97 (19) | 186 (20) | 1.19 (0.92, 1.53) | 0.19 |
| 250–500 m | 83 (17) | 113 (12) | 1.79 (1.23, 2.59) | 0.002 |
| 500–1000 m | 6 (1) | 12 (1) | 1.11 (0.41, 2.97) | 0.84 |
| > 1000 m | 302 (62) | 669 (68) | 1 | |
| Absence of trees within 200 m | 394 (81) | 703 (72) | 1.65 (1.27, 2.15) | 0.0002 |
| Presence of bushes within 200 m | 124 (25) | 194 (20) | 1.38 (1.07, 1.79) | 0.01 |
| Presence of tea within 200 m | 243 (50) | 522 (53) | 0.87 (0.70, 1.08) | 0.21 |
| Presence of maize within 200 m | 445 (91) | 887 (90) | 1.09 (0.74, 1.59) | 0.67 |