Volume 9, Number 2—February 2003
Research
Risk Factors for Sporadic Giardiasis: a Case-Control Study in Southwestern England
Table 2
Single variable analysis of risk factors for giardiasis: recreational water exposures
Swimming and related activities by location and frequency: | Cases (n=192) | Controls (n=492) | Matched odds ratio (95% CI)a | p value | |
---|---|---|---|---|---|
Swimming anywhere |
No |
123 |
406 |
||
Yes |
66 |
85 |
3.9 (2.2 to 7.1) |
<0.0001 |
|
Swallowing water while swimming |
No |
132 |
428 |
||
Yes |
26 |
33 |
6.6 (2.5 to 17.6) |
0.0001 |
|
Frequency of swimming |
0 |
123 |
406 |
||
1–2 |
29 |
44 |
|||
3–4 |
22 |
19 |
|||
5–6 |
6 |
10 |
|||
7–8 |
4 |
11 |
1.3 (1.1 to 1.5)b |
0.002 |
|
In chlorinated water |
|||||
Swimming |
No |
149 |
434 |
||
Yes |
43 |
58 |
2.7 (1.4 to 5.0) |
0.002 |
|
Swallowed water |
No |
174 |
464 |
||
Yes |
18 |
28 |
2.4 (0.9 to 6.0) |
0.07 |
|
Head immersion |
No |
156 |
443 |
||
Yes |
36 |
49 |
2.5 (1.3 to 5.0) |
0.009 |
|
In fresh water |
No |
172 |
469 |
||
Yes |
20 |
23 |
5.1 (2.0 to 12.5) |
0.0003 |
|
Swallowed water |
No |
191 |
491 |
||
Yes |
1 |
1 |
3.9 (0.1 to 136) |
0.4 |
|
Head immersion |
No |
188 |
489 |
||
Yes |
3 |
2 |
26.6 (1.2 to 572) |
0.02 |
|
In sea water | No |
187 |
486 |
||
Yes | 5 | 6 | 1.2 (0.2 to 8.4) | 0.9 |
aCI, confidence intervals.
bFor each additional visit.