Table 2

Dose-response relation between average daily consumption of unboiled tap water and odds of gastroenteritis

Glasses of unboiled tap water/dayCase n = 101 (%)*Control n = 121 (%)*Matched OR95% CI
*Data regarding daily consumption of unboiled tap water were not available for 12 cases and 120 controls.
0–29 (9)43 (35)Ref
3–423 (23)32 (26)1.40.2 to 9.5
5–628 (28)29 (24)3.91.1 to 22.5
>741 (41)18 (15)12.31.9 to 552.4