Table 3.
Unadjusted and adjusted analyses for factors associated with hookworm infection at the 15-month follow-up point
| Proportion infected | Intensity of infection | ||||||
|---|---|---|---|---|---|---|---|
| Variables | Categories | Odds ratio (95% CI) | P | Adjusted odds ratioa (95% CI) | Adjusted P | Epg ratio (95% CI) | P |
| Child characteristics | |||||||
| Sex | Male | 1 | 1 | 1 | |||
| Female | 0.44 (0.20–0.97) | 0.034 | 0.43 (0.20–0.97) | 0.041 | 0.18 (0.03–1.00) | 0.070 | |
| Age group | 5–8 | 1 | 1 | 1 | |||
| 9–10 | 1.93 (0.64–5.82) | 2.01 (0.66–6.07) | 2.95 (0.26–32.67) | ||||
| 11–12 | 1.59 (0.50–5.01) | 0.576 | 1.53 (0.48–4.83) | 0.405 | 1.10 (0.10–12.36) | 0.537 | |
| 13–15 | 2.02 (0.67–6.10) | 1.88 (0.62–5.72) | 4.19 (0.37–47.11) | ||||
| Anemia | Yes | 0.56 (0.24–1.30) | 0.162 | 0.50 (0.21–1.16) | 0.095 | 1.83 (0.27–12.55) | 0.628 |
| Thin | Yes | 1.81 (0.72–4.58) | 0.235 | 1.66 (0.65–4.23) | 0.318 | 5.21 (0.34–78.8) | 0.152 |
| Stunted | Yes | 2.05 (1.00–4.20) | 0.050 | 1.92 (0.93–3.96) | 0.080 | 2.76 (0.20–350.5) | 0.681 |
| Underweight | Yes | 8.46 (2.23–32.01) | 0.005 | 5.50 (1.65–18.28) | 0.006 | 2.87 (0.42–19.77) | 0.258 |
| Baseline infection | |||||||
| Hookworm infection | Yes | 2.02 (1.32–3.09) | 0.001 | 1.63 (0.74–3.61) | 0.225 | 0.79 (0.13–4.84) | 0.804 |
| Hookworm intensity | 0 | 1 | 1 | 1 | |||
| 1–999 | 1.67 (0.75–3.72) | 0.087 | 0.29 (0.08–1.14) | 0.110 | 0.75 (0.13–4.48) | 0.890 | |
| > = 1 000 | 6.19 (1.48–28.88) | 1 | 0.85 (0.00–217.17) | ||||
| Household characteristics | |||||||
| Socioeconomic status | Poor | 1 | 1 | 1 | |||
| Less poor | 0.97 (0.85–1.01) | 0.608 | 0.97 (0.84–1.10) | 0.593 | 1.08 (1.13–8.99) | 0.734 | |
| Water source | Not covered | 1 | 1 | 1 | |||
| Covered | 0.53 (0.12–2.40) | 0.445 | 0.49 (0.11–2.26) | 0.398 | 1.41 (0.10–160.42) | 0.893 | |
| Floor | Mud | 1 | 1 | 1 | |||
| Cemented | 0.97 (0.22–4.31) | 0.977 | 0.97 (0.22–4.31) | 0.970 | 0.34 (0.00–42.88) | 0.700 | |
| Pit latrine | No | 1 | 1 | 1 | |||
| Yes | 0.45 (0.19–1.08) | 0.956 | 0.43 (0.18–1.05) | 0.085 | 0.39 (0.03–5.73) | 0.443 | |
| School characteristics | |||||||
| Baseline school infection level | |||||||
| Hookworm prevalence | <33 | 1 | 1 | 1 | |||
| 34–45 | 0.63 (0.23–1.72) | 0.605 | 0.58 (0.21–1.61) | 0.864 | 0.52 (0.06–4.94) | 0.380 | |
| >45% | 0.96 (0.42–2.17) | 0.91 (0.40–2.06) | 1.94 (0.26–14.32) | ||||
| Hookworm epg | 6–35 | 1 | 1 | 1 | |||
| 44–90 | 1.91 (0.81–4.48) | 0.203 | 1.77 (0.75–4.18) | 0.278 | 3.34 (0.43–26.04) | ||
| 102–453 | 0.98 (0.37–2.62) | 0.97 (0.36–2.59) | 1.04 (0.12–2.62) | 0.187 | |||
| Latrine cleanliness | Clean | 1 | 1 | 1 | |||
| Dirty | 0.40 (0.13–1.19) | 1.77 (0.75–4.18) | 0.127 | 0.74 (0.10–5.68) | |||
| Very dirty | 1.27 (0.56–2.89) | 0.110 | 0.97 (0.36–2.59) | 4.32 (0.46–40.81) | 0.341 | ||
| Children per latrine | <50:1 | 1 | 1 | 1 | |||
| >50:1 | 1.06 (0.51–2.18) | 0.873 | 1.07 (0.52–2.22) | 0.848 | 0.76 (0.32–1.80) | 0.528 | |
| Environmental characteristics | |||||||
| Elevation | 1.00 (0.99–1.00) | 0.300 | 1.00 (0.99–1.00) | 0.344 | 1 | ||
| LST | 0.73 (0.51–1.05) | 0.101 | 1.09 (0.72–1.65) | 0.670 | 0.75 (0.29–1.96) | 0.564 | |
| NDVI | 0.47–0.53 | 1 | 1 | 1 | |||
| 0.54–0.57 | 0.82 (0.33–2.03) | 0.442 | 0.89 (0.36–2.21) | 0.833 | 0.48 (0.06–4.16) | 0.289 | |
| 0.58–0.67 | 1.20 (0.50–2.89) | 1.15 (0.48–2.78) | 1.78 (0.20–16.08) | ||||
| Distance from water bodies | 1.08 (0.46–2.58) | 0.854 | 1.10 (0.46–2.62) | 0.831 | 0.60 (0.08–4.44) | 0.615 | |
Abbreviations: NDVI Normalized difference vegetation index, LST Land surface temperature
Elevation meters above sea level
aAdjusted for sex and hookworm baseline infection