Table 2 Univariate and Multivariate Analyses of Risk Factors using Logistic Regression Analysis

Sex

Female

3565 (97.2)

103 (2.8)

-

-

Male

1150 (95.5)

54 (4.5)

1.63 (1.15–2.26, 0.005)

1.35 (0.94–1.93, 0.102)

Age group

≥ 55 years

705 (97.4)

19 (2.6)

-

-

<55 years

4010 (96.7)

138 (3.3)

1.28 (0.81–2.14, 0.324)

0.97 (0.60–1.65, 0.903)

Tumor upper location

no

3630 (97.3)

99 (2.7)

-

-

yes

1085 (94.9)

58 (5.1)

1.96 (1.40–2.72,0.001)

2.56 (1.80–3.62,0.001)

Tumor size

≤ 7 mm

3308 (98.1)

63 (1.9)

-

-

>7 mm

1407 (93.7)

94 (6.3)

3.51 (2.54–4.87,0.001)

2.59 (1.85–3.65,0.001)

Hashimoto’s thyroiditis

no

3661 (96.9)

118 (3.1)

-

-

yes

1054 (96.4)

39 (3.6)

1.15 (0.78–1.64, 0.463)

1.27 (0.85–1.87, 0.224)

ETE

no

2684 (97.7)

64 (2.3)

-

-

yes

2031 (95.6)

93 (4.4)

1.92 (1.39–2.66,0.001)

1.41 (1.01–1.99, 0.044)

LVI

no

4686 (96.8)

155 (3.2)

-

-

yes

29 (93.5)

2 (6.5)

2.08 (0.34-7.00, 0.318)

1.06 (0.16–3.85, 0.939)

CLNM

0

2980 (98.4)

47 (1.6)

-

-

1–2

1142 (95.7)

51 (4.3)

2.83 (1.89–4.24,0.001)

2.91 (1.93–4.42,0.001)

≥ 3

593 (91.0)

59 (9.0)

6.31 (4.26–9.38,0.001)

5.84 (3.83–8.93,0.001)