Table 2. Cox regression analysis of risk factors in transformation of oral leukoplakia.

	Univariate analysis		Multivariate analysis
Variate	HR (95% CI)	P	HR (95% CI)	P
Gender
Female	1.00
Male	0.66 (0.38–1.15)	0.145
Age (yr)
< = 60	1.00		1.00
>60	1.91 (1.09–3.35)	0.024	2.17 (1.18–4.00)	0.013
Lesion site
Other sites	1.00		1.00
Lateral/ventral tongue	3.38 (1.94–5.87)	<0.001	2.84 (1.55–5.18)	0.001
Lesion type
Homogenous	1.00		1.00
Non-homogenous	3.34 (1.57–7.13)	0.002	2.55 (1.15–5.68)	0.022
Epithelial dysplasia
Low grade	1.00		1.00
High grade	4.33 (2.55–7.36)	<0.001	2.88 (1.64–5.07)	<0.001
Smoking
Never	1.00
Past and present	0.76 (0.38–1.50)	0.427
Alcohol intake
Never	1.00
Past and present	0.87 (0.45–1.70)	0.874

HR, Hazard Ratio. CI: confidence interval.