Table A1. Single variable analysis (chi-square test or Fisher exact test) of significant and selected nonsignificant variables^a.

Variables	Case-patients	Controls	OR	95% CIs	p value
General information
Sex
M	204	190	1.02	0.76–1.35	0.967
F	222	210
Have a medical condition known to affect immunity
Y	17	3	5.67	1.54–4.78	0.004
N	376	376
No. of persons 5–15 years living with you
0	115	63			< 0.001b
1	115	103	0.61	0.40–0.94
2	39	53	0.40	0.23–0.70
3	12	11	0.60	0.23–1.59
4	2	4	0.27	0.00–21.70
>5	0	1	0.00	0.00–21.70
Travel outside UK
Y	99	24	4.74	2.89–7.85	< 0.001
N	327	376
Gardening other than watering
Y	62	90	0.61	0.42–0.89	0.009
N	345	306
Swimming pool use
Swim in a swimming pool
Y	172	147	1.15	0.86–1.55	0.362
N	252	248
No. of times swum in a swimming pool
0	252	248			< 0.001b
1	38	46	0.81	0.50–1.33
2	39	52	0.74	0.46–1.19
3	18	17	1.04	0.50–2.18
4	13	11	1.16	0.48–2.84
>5	53	18	2.90	1.60–5.29
Use a toddler pool
Y	76	50	1.52	1.01–2.28	0.043
N	345	344
No. of times swum in toddler pool
0	345	344			0.001b
1	16	16	1.00	0.47–2.14
2	21	22	0.95	0.49–1.84
3	5	4	1.25	0.27–6.33
4	6	3	1.99	0.42–12.41
>5	18	1	17.95	2.80–749.91
Contact with animals
Touch or handle any farm animals
Y	70	43	1.65	1.07–2.54	0.021
N	344	348
Touch any cattle
Y	22	8	2.69	1.11–6.70	0.024
N	392	383
Domestic pets living in home
Y	207	214	0.82	0.62–1.09	0.180
N	219	186
Contact with case-patients
Anyone else in previous 2 weeks in house ill with diarrhea
Y	83	28	3.20	1.98–5.20	< 0.001
N	334	361
Contact with another person ill with diarrhea
Y	91	24	4.27	2.59–7.10	< 0.001
N	324	365
Contact with children <5 y
Toileting contact with a child <5 y
Y	86	52	1.69	1.14–2.51	0.008
N	341	348
Diaper-changing contact with a child <5 y
Y	71	48	1.46	0.96–2.22	0.073
N	356	352
Drinking water consumption
Did you drink unboiled tap water at home
Y	347	342	0.82	0.54–1.23	0.359
N	67	54
No. of glasses of tap water drunk a day
0	67	54			0.037b
1	54	65	0.67	0.39–1.15
2	57	74	0.62	0.37–1.05
3	65	88	0.60	0.36–0.99
4	47	57	0.66	0.38–1.16
>5	73	33	1.78	1.00–3.19
Use a water filter at home
Y	39	34	1.11	0.66–1.85	0.771
N	373	360
Disruption to your water supply at home
Y	27	25	1.19	0.65–2.18	0.650
N	321	353
Any water discoloration
Y	22	16	1.33	0.6–6–2.72	0.490
N	392	380
Any altered taste to the water
Y	14	4	3.43	1.03–12.57	0.040
N	400	392
Any loss of water pressure
Y	11	13	0.80	0.33–1.95	0.751
N	403	383
Any other problems with water
Y	17	11	1.50	0.65–3.49	0.400
N	397	385
Did you drink unboiled tap water at somewhere other than home
Y	212	193	1.16	0.85–1.58	0.352
N	153	162
Did you use ice cubes
Y	120	113	1.05	0.76–1.45	0.813
N	277	274
No. of times ice cubes were used
0	277	274			0.944b
1	13	12	1.07	0.45–2.56
2	17	24	0.70	0.35–1.39
3	15	20	0.74	0.35–1.55
4	19	9	2.09	0.88–5.08
>5	30	31	0.96	0.55–1.68
Drink any bottled water
Y	164	148	1.13	0.83–1.52	0.457
N	228	232
No. of glasses of bottled water a day
0	228	232			0.018a
1	31	49	0.64	0.38–1.07
2	34	37	0.94	0.55–1.59
3	12	12	1.02	0.42–2.48
4	16	9	1.81	0.74–4.53
>5	21	8	2.67	1.10–6.71
Consumption of raw vegetables or salads
Eat lettuce
Y	161	186	0.75	0.55–1.01	0.057
N	212	183
Eat other green salad
Y	165	204	0.61	0.45–0.83	0.001
N	194	146
Eat tomatoes
Y	195	249	0.54	0.39–0.73	< 0.001
N	184	126
Eat coleslaw
Y	83	116	0.62	0.44–0.89	0.007
N	267	233
Eat raw vegetables
Y	94	157	0.45	0.33–0.63	< 0.001
N	259	196
Eat fresh fruit
Y	332	361	0.36	0.20–0.63	< 0.001
N	54	21
Consumption of dairy products
Eat uncooked soft cheese
Y	85	116	0.65	0.46–0.91	0.012
N	270	238
Eat uncooked hard cheese
Y	243	281	0.59	0.42–0.83	0.002
N	125	85
Eat ice cream
Y	249	284	0.55	0.39–0.78	< 0.001
N	127	80
Eat or drink cream
Y	86	124	0.60	0.42–0.84	0.003
N	259	223
Area of residence
Health authority
A	40	19			< 0.001
B	14	46	0.14	0.06–0.32
C	0	0	n.e.	n.e.
D	40	37	0.51	0.25–1.04
E	8	4	0.95	0.25–3.55
F	32	58	0.26	0.13–0.53
G	7	7	0.48	0.15–5.55
H	17	10	0.81	0.31–2.09
I	0	0	n.e.	n.e.
J	42	51	0.39	0.20–0.77
K	1	1	0.48	0.83–8.01
L	5	4	0.59	0.14–2.47
M	43	29	0.70	0.34–1.45
N	24	10	1.14	0.46–2.85
O	27	23	0.56	0.26–1.22
P	15	6	1.19	0.40–3.54
Q	1	0	n.e.	0.0004–¥
R	24	23	0.50	0.22–1.09
S	8	17	0.22	0.08–0.61
T	5	10	0.24	0.07–0.79
U	74	45	0.78	0.40–1.51

^aOR, odds ratio; CI, confidence interval; n.e., not estimable.
^bChi-square test for trend.