Volume 9, Number 12—December 2003
    
    Research
Risk Factors for Norovirus, Sapporo-like Virus, and Group A Rotavirus Gastroenteritis
Table 1
Risk factors for NV gastroenteritis, prevalence in cases and controls (152 pairs), and univariate and multivariate odds ratios using logistic regression and population-attributable risk fractionsa
| NV gastroenteritis | Cases n (%) | Controls n (%) | OR uni | 95% CI | OR multi | 95% CI | PAR (%) | |
|---|---|---|---|---|---|---|---|---|
| Food-handling hygieneb | 
1.3 | 
1.0 to 1.5 | 
1.3 | 
1.0 to 1.7 | 
47 | 
|||
| Educational level | 
n.i. | 
|||||||
| Low | 
21 (14.3) | 
16 (10.9) | 
1.9 | 
0.9 to 4.0 | 
||||
| Intermediate | 
58 (39.5) | 
80 (54.4) | 
1.0 | 
- | 
||||
| High | 
68 (46.3) | 
51 (34.7) | 
2.2 | 
1.2 to 3.9 | 
||||
| Participant to daycare center | 
47 (30.9) | 
37 (24.7) | 
1.7 | 
0.9 to 3.3 | 
n.i. | 
|||
| Household member to daycare center | 
34 (23.5) | 
21 (14.5) | 
2.0 | 
1.0 to 3.9 | 
n.i. | 
|||
| Household member to primary school | 
62 (42.8) | 
48 (33.1) | 
1.6 | 
1.0 to 2.7 | 
n.i. | 
|||
| Pets in household | 
85 (56.3) | 
102 (67.6) | 
0.6 | 
0.4 to 1.0 | 
n.i. | 
|||
| Cat as pet | 
46 (30.5) | 
61 (40.4) | 
0.6 | 
0.4 to 1.0 | 
n.i. | 
|||
| No. of household members with gastroenteritisc | 
17 | 
|||||||
| None | 
73 (48.3) | 
130 (85.8) | 
1.0 | 
- | 
1.0 | 
- | 
||
| 1 | 
39 (25.8) | 
15 (10.0) | 
3.7 | 
1.7 to 8.0 | 
1.2 | 
0.3 to 4.2 | 
||
| >1 | 
39 (25.8) | 
6 (4.2) | 
13.1 | 
3.9 to 34.7 | 
10.9 | 
2.0 to 60.5 | 
||
| Contact with persons outside household with gastroenteritisc | 
56 | 
|||||||
| No | 
50 (32.9) | 
101 (66.5) | 
1.0 | 
- | 
1.0 | 
- | 
||
| Yes | 
57 (37.5) | 
8 (5.3) | 
11.4 | 
4.7 to 27.3 | 
12.7 | 
3.1 to 51.8 | 
||
| Do not know | 
45 (29.6) | 
43 (28.3) | 
1.9 | 
1.1 to 3.4 | 
2.5 | 
1.0 to 6.5 | 
||
| Consumption of fishc | 
46 (34.6) | 
32 (24.1) | 
1.8 | 
1.0 to 3.2 | 
n.i. | 
|||
| Consumption of barbecued foodc | 1 (1.5) | 9 (6.6) | 0.2 | 0.05 to 1.0 | n.i. | |||
aNV, norovirus; OR, odds ratio; PAR, population-attributable risk fractions; uni, univariate; multi, multivariate; CI, confidence interval; n.i, not in final model; -, not applicable.
bBasic score (not optimized), higher score indicates less hygienic practices, OR for increase of 1.
cIn the week before onset of symptoms (case-patients), inclusion in study (control).
1Current address of first author: Municipal Health Service, Department of Epidemiology, Documentation and Health Promotion, Nieuwe Achtergracht 100, 1018 WT Amsterdam, the Netherlands; email: mdwit@gggd.amsterdam.nl