Table 1

Matched univariate analysis (matched "Mantel-Haenszel" odds ratio: mOR) and multivariate conditional logistic regression analysis (adjusted odds ratio: aOR). Cases of Norovirus infection (n = 41) and Controls (n = 41) according to investigated risk factors




Univariate analysis
Multivariate analysis


Risk factors(*)
Cases (%)
Controls (%)
mOR
95% CI
p-value
aOR
95% CI
p-value

Ice
21/41 (51)
12/41 (29)
4.1
(0.9–7.1)
0.04
16.4
(1.8–250.9)
0.04
Eggs
2/41 (5)
8/41 (19)
2.3
(0.1–1.7)
0.12
-
-
-
Grilled sausage
21/41 (51)
25/41 (61)
0.7
(0.2–1.7)
0.17
-
-
-
Ham
1/41 (2)
5/41 (12)
2.8
(0.1–1.7)
0.09
-
-
-
Grilled meat
11/41 (27)
15/41 (37)
3.5
(0.1–1.1)
0.06
-
-
-
Snacks
20/41 (49)
19/41 (46)
0.1
(0.4–2.8)
0.15
-
-
-
Raw mussels
22/41 (54)
13/41 (31)
3.9
(0.9–6.8)
0.04
25.5
(1.5 – 442.9)
0.03

(*) In the univariate analysis, only Risk Factors with p-value<0.20 are reported; in the multivariate analysis, only variables selected by the conditional logistic model according to a log-likelihood-ratio test for goodness-of-fit are reported.

Rizzo et al. BMC Infectious Diseases 2007 7:135   doi:10.1186/1471-2334-7-135