Table 4.

Diarrhea prevalence by level of water contamination

Escherichia coli concentration/100 mL drinking water	No. of diarrhea measurements	Prevalence (%) of diarrhea in subsequent evaluation	Prevalence ratio (95% confidence interval)
Reported diarrhea 3–100 days after water sample collection (N = 24,334)
< 1	4,993	8.4	Reference
1–9	2,751	8.6	1.02 (0.83, 1.26)
10–99	2,700	9.9	1.17 (0.92, 1.49)
100–999	1,382	14.1	1.68 (1.30, 2.17)
≥ 1,000	366	11.7	1.39 (0.93, 2.10)
Reported diarrhea 3–46 days after water sample collection (N = 12,103)
< 1	2,426	7.8	Reference
1–9	1,345	9.4	1.20 (0.95, 1.52)
10–99	1,286	9.3	1.19 (0.89, 1.62)
100–999	696	14.1	1.81 (1.35, 2.41)
≥ 1,000	177	13.6	1.74 (1.09, 2.78)