Table 4 Logistic regression model evaluating which symptoms best predicted incapacitation due to travelers' diarrhea.

Characteristic All with TD n = 160 Conducted program as planned n = 107 Incapacitated n = 53 Univariate OR [95% CI] p-value Multivariate OR [95% CI]
Stool frequency      < 0.001
3 stools/day 76 (48) 64 (60) 12 (23) 1.0   1.0
4-5 stools/day 58 (36) 35 (33) 23 (43) 3.51 [1.56-7.88]   2.05 [0.77-5.43]
> 5 stools/day 26 (16) 8 (8) 18 (34) 12.0 [4.26-33.8]   4.84 [1.40-16.8]
Abdominal cramps      0.005
No abdominal cramps 37 (23) 32 (30) 5 (9) 1.0   1.0
1 -3 days 95 (59) 62 (58) 33 (62) 3.41 [1.21-9.57]   1.86 [0.55-6.34]
> 3 days 28 (18) 13 (12) 15 (28) 7.39 [2.22-24.5]   2.64 [0.62-11.3]
Fecal urgency 1 114 (71) 69 (65) 45 (85) 3.10 [1.32-7.25] 0.009 0.93 [0.32-2.70]
Nausea 2 61 (38) 25 (23) 36 (68) 6.95 [3.35-14.4] < 0.001 4.38 [1.70-11.3]
Vomiting 3 32 (20) 13 (12) 19 (36) 4.04 [1.80-9.06] 0.001 0.96 [0.32-2.91]
Fever 4 25 (16) 6 (6) 19 (36) 9.41 [3.47-25.5] < 0.001 5.65 [1.80-17.7]
1. TD: travelers' diarrhea; OR: odds ratio; CI: confidence interval. P-values based on χ2-tests for categorical variables. Variables with p < 0.2 were included in the multivariate logistic regression model. Reference category: 1no fecal urgency, 2no nausea, 3no vomiting, 4no fever. Model: constant = 0.06, Nagelkerke's R2 = 0.42, Hosmer and Lemeshow test for goodness of fit p = 0.7.