Volume 9, Number 2—February 2003
Research
Risk Factors for Sporadic Giardiasis: a Case-Control Study in Southwestern England
Table 1
Single variable analysis of risk factors for giardiasis: drinking water exposures
Risk factor | Cases (n=192) | Controls (n=492) | Matched odds ratio (95% CI)a | p value | |
---|---|---|---|---|---|
Consumed tap water |
No |
17 |
79 |
||
Yes |
174 |
410 |
2.3 (1.1 to 4.9) |
0.02 |
|
Usual no. of glasses of tap water consumed per day (glass=approx 1/3 pint) |
0.0 |
17 |
79 |
||
0.5–1.0 |
22 |
71 |
|||
1.5–2.0 |
52 |
150 |
|||
2.5–3.0 |
23 |
46 |
|||
3.5–4.0 |
23 |
41 |
|||
4.5–5.0 |
20 |
41 |
|||
>5.0 |
33 |
61 |
1.2 (1.1 to 1.4)b |
<0.0001 |
|
Consumed bottled water |
No |
154 |
406 |
||
Yes |
38 |
83 |
1.6 (0.9 to 2.9) |
0.1 |
|
Usual no. of glasses of bottled water consumed per day |
0 |
154 |
406 |
||
1 |
12 |
29 |
|||
2 |
19 |
32 |
|||
3 |
5 |
13 |
|||
4 |
1 |
8 |
1.2 (0.9 to 1.6)b |
0.3 |
|
Used water filter at home |
No |
157 |
387 |
||
Yes |
34 |
104 |
0.9 (0.5 to 1.7) |
0.8 |
|
Type of water supply |
Public |
187 |
483 |
||
Private |
3 |
3 |
0.05 (0.002 to 1.11) |
0.04 |
|
Had a disruption in the water supply | No |
124 |
447 |
||
Yes | 6 | 11 | 3.6 (0.6 to 20.8) | 0.2 |
aCI, confidence intervals.
bFor each additional glass.