Institutional risk factors for norovirus outbreaks in Hong Kong elderly homes: a retrospective cohort study

BMC Public Health

Tables 1 Crude RRs and 95% Cls for potential risk factors related to norovirus outbreaks in Hong Kong elderly homes

Factors	Home-years	Outbreaks	RR	95% CI	P value
Home capacity (per 30-resident increment)			1.5	1.4-1.6	<0.0001
Staff-to-resident ratio (per 1/30 increment)			1.2	1.1-1.3	<0.0001
% residents older than 75 yrs (per additional 10%)			1.2	1.1-1.3	0.0003
% bedridden residents (per additional 10%)			0.9	0.8-1.0	0.07
Infection control training
No	1024	1	1
Yes	8259	275	3.5	0.5-25.6	0.2
Visits by CGAT
No	15302	41	1
Yes	6831	235	1.3	0.9-2.0	0.2
Visits by medical officers
No	267	14	1
Yes	8094	262	0.6	0.3-1.1	0.1
Isolation area
No	2865	101	1
Yes	5496	175	0.9	0.7-1.2	0.5
Air conditioner supply
No	157	12	1
Yes	8204	264	0.4	0.2-1.1	0.1
Hygiene condition of toilets
High	113	2	1
Low	8248	274	1.9	0.5-7.4	0.3
Hygiene condition of kitchens
High	438	13	1
Low	7923	263	1.1	0.7-1.9	0.7
Wheelchair accessibility
No	1794	21	1
Yes	6567	255	3.5	2.2-5.6	<0.0001
Partition between beds
No	2111	151	1
Yes	6251	125	0.25	0.19-0.34	<0.0001

ISSN: 1471-2458