The Effect of Iodine Status on the Risk of Thyroid Nodules: A Cross-Sectional Study in Zhejiang, China

Table 1

Summary statistics of variables between nonthyroid nodule and thyroid nodule groups.

Variables	Nonthyroid nodule (n = 2290)	Thyroid nodule (n = 420)	Total (n = 2710)
Gender^a				0.00
Female	1108 (81.7)	249 (18.4)	1357 (50.1)
Male	1182 (87.4)	171 (12.6)	1353 (49.9)
Age (year^b)	42.40 (15.8)	50.09 (15.5)	43.0 (25.0)	0.00
Age group^a				0.00
18–29	608 (91.8)	54 (8.2)	662 (24.4)
30–39	478 (88.4)	63 (11.7)	541 (20.0)
40–49	487 (85.0)	86 (15.0)	573 (21.1)
50–59	340 (79.1)	90 (20.9)	430 (15.9)
60–69	223 (75.1)	74 (24.9)	297 (11.0)
≥70	154 (74.4)	53 (25.6)	207 (7.6)
Education^a
Illiteracy/primary school	521 (79.4)	135 (20.6)	656 (24.2)
Junior middle school	687 (83.5)	136 (16.5)	823 (30.4)
High school/technical secondary school	476 (87.8)	66 (12.2)	542 (20.0)
University/college/graduate student	606 (88.0)	83 (12.0)	689 (25.4)
Profession^a				0.00
Physical labor	932 (84.4)	172 (15.6)	1104 (40.7)
Agricultural labor	275 (76.0)	87 (24.0)	362 (13.4)
Mental labor	694 (88.5)	90 (11.5)	784 (28.9)
Others	389 (84.6)	71 (15.4)	460 (17.0)
Income, thousand yuan^a				0.06
<10	252 (88.1)	34 (11.9)	286 (10.6)
10–29	367 (82.8)	76 (17.2)	443 (16.4)
30–49	626 (82.0)	137 (18.0)	763 (28.2)
50–99	636 (85.6)	107 (14.4)	743 (27.4)
≥100	409 (86.1)	66 (13.9)	475 (17.5)
Region^a				0.41
County	1119 (85.1)	196 (14.9)	1315 (48.5)
District	1171 (83.9)	224 (16.1)	1395 (51.5)
Smoke^a				0.94
No	1874 (84.5)	343 (15.5)	2217 (81.8)
Yes	416 (84.4)	77 (15.6)	493 (18.2)
Passive smoke^a				0.82
No	1648 (84.6)	300 (15.4)	1948 (71.9)
Yes	642 (84.3)	120 (15.7)	762 (28.1)
Family history of thyroid diseases^a				0.60
No	2194 (84.6)	400 (15.4)	2594 (95.7)
Yes	96 (82.8)	20 (17.2)	116 (4.3)
Hypertension^a				0.00
No	1724 (86.1)	278 (13.9)	2002 (73.9)
Yes	566 (79.9)	142 (20.1)	708 (26.1)
BMI (kg/m^2b)	23.4 (3.4)	24.2 (3.2)	23.6 ± 3.4	0.00
Waist circumference (cm^b)	80.8 (9.5)	84.7 (8.8)	81.4 ± 9.5	0.00
Heart rate (times/minute^b)	79.7 (11.7)	80.2 (11.2)	79.8 ± 11.6	0.41
FBG (mmol l^−1b)	5.5 (1.5)	5.7 (1.3)	5.5 ± 1.5	0.00
OGTT-2h (mmol l^−1b)	5.9 (2.2)	6.3 (2.4)	5.9 ± 2.2	0.00
HbA1c^b	5.4 (1.1)	5.6 (0.8)	5.5 ± 1.0	0.00
TG (mmol l^−1b)	1.6 (2.9)	1.6 (1.4)	1.6 ± 2.7	0.96
TC (mmol l^−1b)	4.6 (1.3)	5.0 (1.1)	4.7 ± 1.3	0.00
LDL-C (mmol l^−1b)	2.8 (0.8)	3.1 (0.9)	2.9 ± 0.8	0.00
HDL-C (mmol l^−1b	1.6 (0.5)	1.6 (0.4)	1.6 ± 0.5	0.32
UA (mmol l^−1b)	297.1 (169.8)	285.1 (84.7)	295.2 ± 159.7	0.03
TSH (mIU l^−1c)	2.2 (1.8)	2.0 (1.4)	2.2 (1.73)	0.00
Overt hyperthyroidism^a				1.00
No	2282 (84.5)	419 (15.5)	2701 (99.7)
Yes	8 (88.9)	1 (11.1)	9 (0.3)
Subclinical hyperthyroidism^a				0.05
No	2287 (84.6)	417 (15.4)	2704 (99.8)
Yes	3 (50)	3 (50)	6 (0.2)
Overt hypothyroidism^a				1.00
No	2275 (84.5)	418 (15.5)	2693 (99.4)
Yes	15 (88.2)	2 (11.8)	17 (0.6)
Subclinical hyperthyroidism^a				0.05
No	1989 (84.5)	366 (15.5)	2355 (86.9)
Yes	314 (88.5)	41 (11.5)	355 (13.1)
TPOAb (IU l^−1c)	11.5 (5.7)	11.8 (5.7)	11.6 (5.7)	0.94
TGAb (IU l^−1c)	12.5 (6.7)	13.2 (7.3)	12.6 (7.0)	0.00
Iodized salt^a				0.00
No	706 (71.8)	277 (28.2)	983 (36.3)
Yes	1584 (91.7)	143 (8.3)	1727 (63.7)
UIC (μg l^−1C)	164.0 (134.6)	122.9 (110.3)	158 (134.2)	0.00
UIC (μg l^−1a)				0.00
<100	541 (23.6)	158 (37.6)	699 (25.8)
100–199	917 (40)	165 (39.3)	1082 (39.9)
200–299	530 (23.1)	63 (15)	593 (21.9)
≥300	302 (13.2)	34 (8.1)	336 (12.4)

^aExpression with the number (proportion %), tested with the chi-square test. ^bExpression with mean (SD), tested with the t-test. ^cExpression with median (IQR), tested with the Wilcoxon method.