Multicenter case-control study of the risk factors for ulcerative colitis in China

Table 1 Social characteristics and household factors between ulcerative colitis and healthy controls

Variables	UC	Control	P value	OR	95%CI
Living area
Rural	16.4%	15.7%
Town	16.6%	12.9%	0.617	0.930	0.702-1.234
City	67.0%	71.4%	0.054	0.711	0.569-1.887
Education
Primary or below	14.3%	13.2%
Secondary	39.7%	36.8%	0.959	0.994	0.781-1.265
College or above	46.0%	50.0%	0.164	0.846	0.669-1.071
Feeling stress
None	21.5%	21.3%
Occasionally	55.6%	66.5%	0.056	0.828	0.682-1.005
Often	22.9%	12.2%	0.000	1.858	1.440-2.398
Water source
Boiled well or tap water water	82.0%	68.5%
Well water	3.4%	1.9%	0.118	1.494	0.903-2.471
Tap water	5.4%	21.6%	0.000	0.21	0.159-0.279
Mineral water	9.2%	8.0%	0.758	0.957	0.723-1.267
Lavatory
Closestool	11.3%	9.8%
Squat pan	39.4%	41.6%	0.173	0.829	0.634-1.085
Flush toilet	49.3%	48.6%	0.368	0.886	0.680-1.154
Refrigerator	78.7%	81.1%	0.181	0.86	0.690-1.073

UC: Ulcerative colitis; OR: Odds ratio.

Table 2 Dietary factors between ulcerative colitis and healthy controls

Variables	UC	Control	P value	OR	95%CI
Milk
None or rare	23.9%	24.5%
Light	55.8%	58.5%	0.845	0.981	0.806-1.293
Heavy	20.3%	16.9%	0.096	1.237	0.963-1.590
Tea intake
None or rare	18.5%	17.7%
Light	50.5%	42.3%	0.231	1.139	0.921-1.409
Heavy	30.9%	40.0%	0.007	0.738	0.591-0.922
Alcohol
None or rar	40.5%	47.0%
Light	46.9%	43.0%	0.005	1.264	1.073-1.490
Heavy	12.5%	10.0%	0.005	1.453	1.122-1.882
Spicy food consumption
None or rare	11.1%	25.2%
Light	50.6%	47.4%	0.000	2.432	1.943-3.043
Heavy	38.3%	27.4%	0.000	3.189	2.513-4.046
Sugar			0.000	1.989	1.718-2.301
None or rare	12.3%	31.8%
Light	64.8%	53.1%	0.000	3.162	2.480-4.032
Heavy	23.0%	15.2%	0.000	3.390	2.921-5.288
Vegetable and meat
Vegetarian	13.3%	12.4%
Meat-eaters	10.4%	9.4%	0.421	0.909	0.720-1.147
Balanced diet	76.3%	78.2%	0.848	1.032	0.745-1.432

UC: Ulcerative colitis; OR: Odds ratio.

Table 3 Smoking, breast feeding and medical history between ulcerative colitis and healthy controls

Variables	UC	Control	P value	OR	95%CI
Smoking
Nonsmoker	74.8%	74.5%
Current smoker
< 10 cigarettes per day	13.5%	13.4%	0.982	1.003	0.798-1.259
> 10 cigarettes per day	7.7%	8.9%	0.292	0.859	0.648-1.139
Ex-smoker	4.0%	3.2%	0.272	1.264	0.832-1.922
Breast feeding	46.5%	53.5%	0.628	1.080	0.790-1.477
Infectious diarrhea	14.1%	9.3%	0.000	1.610	1.256-2.064
Appendectomy	3.4%	3.2%	0.737	0.929	0.602-1.432
NSAIDs	9.0%	7.2%	0.209	1.269	0.875-1.841
Measles	9.4%	8.2%	0.286	1.162	0.882-1.532
Parasite	15.7%	11.2%	0.053	1.486	0.946-1.926
Oral contraceptive	6.3%	5.2%	0.082	2.734	0.880-8.495

UC: Ulcerative colitis; NSAIDs: Nonsteroidal anti-inflammatory drugs; OR: Odds ratio.