TABLE 3.
Associations between fecal concentrations of adaptive immune-response cytokines and risk of Giardia lamblia infection ending by treatment arm1
| Placebo group |
Vitamin A group |
||||||||
| Cytokine | No. of infections | Infection duration | Hazard ratio (95% CI) | P | No. of infections | Infection duration | Hazard ratio (95% CI) | P | P for interaction |
| d | d | ||||||||
| IL-4 | |||||||||
| ND | 6 | 13.16 ± 1.162 | 1 | — | 6 | 18.80 ± 4.24 | 1 | — | — |
| Less than the median | 5 | 23.51 ± 4.24 | 0.30 (0.07, 1.25) | 0.1 | 3 | 15.95 ± 4.24 | 1.43 (0.34, 5.98) | 0.62 | <0.01 |
| At least the median | 6 | 36.80 ± 3.24 | 0.12 (0.24. 0.58) | <0.01 | 3 | 12.3 ± 3.82 | 2.64 (0.61, 11.32) | 0.19 | <0.01 |
| IL-5 | |||||||||
| ND | 10 | 17.36 ± 21.79 | 1 | — | 8 | 15.56 ± 5.79 | 1 | — | — |
| Less than the median | 3 | 56.73 ± 12.30 | 0.02 (0.003, 1.18) | <0.01 | 2 | 19.44 ± 13.30 | 0.94 (0.18, 4.91) | 0.95 | <0.01 |
| At least the median | 3 | 44.90 ± 14.95 | 0.05 (0.01, 0.31) | <0.01 | 6 | 12.12 ± 7.46 | 1.94 (0.33, 11.41) | 0.46 | <0.01 |
| IFN-γ | |||||||||
| ND | 10 | 16.23 ± 5.0 | 1 | — | 8 | 19.8 ± 4.24 | 1 | — | — |
| Less than the median | 5 | 12.37 ± 3.0 | 0.60 (0.14, 2.40) | 0.47 | 2 | 13.42 ± 0.86 | 0.19 (0.03, 1.21) | 0.08 | 0.21 |
| At least the median | 4 | 27.16 ± 1.07 | 0.02 (0.004, 0.10) | 0.65 | 6 | 16.8 ± 3.41 | 1.77 (0.19, 15.84) | 0.6 | <0.01 |
IL, interleukin; ND, nondetectable; IFN-γ, interferon-γ. Risk of infection ending, infection duration, and P values were calculated after fitting Weibull's hazard model to the length of infection duration, which was defined as the time from the midpoint between a negative stool sample and a subsequent positive stool sample and between the last sequentially positive stool sample and subsequent negative stool sample. Reference groups were stool samples with no detectable concentrations of cytokine or chemokine; the presence or absence of diarrheal symptoms was included in models.
Mean ± SD (all such values).