A foodborne acute gastroenteritis outbreak caused by GII.P16-GII.2 norovirus in a boarding high school, Beijing, China: a case–control study

Table 1 Results of statistical analysis for suspected risk factors

Suspected risk factors	Cases	Controls	χ²	P-values	OR(95% CI)
12-Dec supper	20	20
Cafeteria 1	10	10	0.000	1.000	1.000 (0.290–3.454)
Cafeteria 2	10	10			1.000
12-Dec lunch	24	26
Cafeteria 1	19	13	4.608	0.032*	3.800 (1.089–13.258)
Cafeteria 2	5	13			1.000
12-Dec breakfast	19	20
Cafeteria 1	9	9	–	1.000^a	1.100 (0.312–3.877)
Cafeteria 2	10	11			1.000
11-Dec supper	19	18
Cafeteria 1	14	13	–	1.000^a	1.077 (0.252–4.597)
Cafeteria 2	5	5			1.000
11-Dec lunch	25	26
Cafeteria 1	10	11	0.028	0.867	0.909 (0.298–2.775)
Cafeteria 2	15	15			1.000
11-Dec breakfast	20	18
Cafeteria 1	12	7	–	0.330^a	2.357 (0.640–8.677)
Cafeteria 2	8	11			1.000
Barreled water	27	27
Yes	20	24	1.964	0.161	0.357 (0.082–1.564)
No	7	3			1.000
Boiled water	27	27
Yes	8	9	0.086	0.770	0.842 (0.267–2.660)
No	19	18			1.000
Wash hands after toilet	26	27
Never	0	0	0.146	0.702^b	–
Sometimes	2	0
Often	6	12
Always	18	15
Wash hands before meal	26	27
Never	0	4	0.324	0.569^b	–
Sometimes	11	7
Often	9	10
Always	6	6
Like cold/uncooked food	26	27
Never	7	7	0.107	0.744^b	–
Sometimes	9	10
Often	7	9
Always	3	1
Auxiliary class	27	27
Yes	13	17	1.200	0.273	1.831 (0.618–5.425)
No	14	10			1.000

ISSN: 1756-0500