Table 2. Factors Affecting Central Lymph Node Metastasis .

Factors	CLNM (-)		CLNM (+)		P Value	OR	95% CI
	n	%	n	%
Age group (n = 255)
< 45 years	71	40.1%	106	59.9%	0.016	0.52	0.3–0.89
≥ 45 years	44	56.4%	34	43.6%
χ2 = 5.808
Gender (n = 255)
Men	20	32.8%	41	67.2%	0.027	1.97	1.13–3.72
Women	95	49.0%	99	51.0%
χ2 = 4.908
Intra-thyroidal localization (n = 236)
Superior	45	69.2%	20	30.8%	< 0.001	NA	0.25–0.44
Middle	22	48.9%	23	51.1%
Inferior	13	22.0%	46	78.0%
Isthmus/junction	15	37.5%	25	62.5%
Multilobar	9	33.3%	18	66.7%
χ2 = 30.705
Tumor subtype (n = 255)
Classic	80	43.2%	105	58.8%	0.010	NA	0.09–0.29
Follicular variant	30	61.2%	19	38.8%
Others	5	23.8%	16	76.2%
χ2 = 9.248
Lymphovascular invasion (n = 255)
No	99	94.3%	6	5.7%	< 0.001	159.13	56.36–449.31
Yes	16	10.7%	134	89.3%
χ2 = 174,424
Extracapsular invasion (n = 255)
No	104	46.9%	129	53.1%	0.007	10.04	1.27–79.07
Yes	1	8.3%	11	91.7%
χ2 = 6.874

CLNM, central lymph node metastasis; OR, odds ratio; CI, confidence interval; NA, not applicable.