Table 1.

Univariate and stepwise logistic regression on possible risk factor for gingival bleeding

Factor	Univariate					Stepwise
	p value	OR	95% CI for OR		p value	OR	95% CI for OR
Gender
Male	< 0.001	1.12	1.09	1.15	< 0.001	1.11	1.08	1.14
Femalea
Age	< 0.001				< 0.001
12		0.77	0.74	0.79	< 0.001	0.75	0.72	0.78
13		0.82	0.79	0.85	< 0.001	0.81	0.78	0.84
14		0.85	0.82	0.88	< 0.001	0.83	0.80	0.86
15a
Region	< 0.001				< 0.001
East		0.81	0.79	0.84	< 0.001	0.86	0.83	0.89
West		1.19	1.15	1.22	.004	1.05	1.02	1.09
Centrala
Living place
Urban	< 0.001	1.06	1.04	1.09	0.001	1.10	1.07	1.13
Rurala
Ethnic group
Han	< 0.001	0.67	0.65	0.70	< 0.001	0.77	0.74	0.80
Minoritya
Family structure
One-child family	< 0.001	0.74	0.73	0.76	< 0.001	0.81	0.79	0.84
With siblingsa
Father education	< 0.001				.001
Middle school		1.50	1.44	1.56	.005	1.09	1.03	1.15
High school		1.29	1.25	1.34	< 0.001	1.09	1.04	1.15
Univeristya
Mother education	< 0.001				.045
Middle school		1.50	1.44	1.56	.041	1.06	1.00	1.12
High school		1.25	1.21	1.30	.397	1.02	.97	1.07
Univerisitya
Smoking
Yes	< 0.001	1.20	1.15	1.26
Noa
Brush teeth
Yes	< 0.001	0.64	0.61	0.66	< 0.001	0.69	0.66	0.73
Noa
Dental floss
Yes	< 0.001	0.81	0.78	0.84	< 0.001	0.89	0.85	0.93
Noa
Oral health knowledge	< 0.001				< 0.001
0–3		1.32	1.28	1.36	< 0.001	1.21	1.16	1.25
4–5		1.18	1.15	1.22	< 0.001	1.12	1.09	1.16
6–8a
Oral health attitude
Negative	0.002	1.04	1.02	1.97
Positivea
Constant					< 0.001	2.83

^aReference category