Association between Urinary Iodine Concentration and Thyroid Nodules in Adults: A Cross-Sectional Study in China

Table 3

Associations between each 100 μg/L increase in UIC and thyroid nodules in subgroups^a.

Variables		OR (95% CI)		interaction
Age, years				0.579
<30	2281	0.89 (0.78, 1.01)	0.075
30 to <40	2856	0.89 (0.81, 0.99)	0.025
40 to <50	2788	0.93 (0.86, 1.01)	0.097
50 to <60	2418	0.96 (0.90, 1.03)	0.309
60 to <70	1293	0.88 (0.80, 0.97)	0.012
≥70	1047	0.96 (0.87, 1.06)	0.406
BMI^b, kg/m^2				0.798
<18.5	547	0.96 (0.78, 1.18)	0.681
18.5 to <24	6177	0.89 (0.84, 0.94)	<0.001
24 to <28	4350	0.88 (0.83, 0.94)	<0.001
≥28	1450	0.94 (0.85, 1.04)	0.204
TSH^c, mIU/L				0.147
<0.27	152	0.87 (0.61, 1.23)	0.432
0.27 to <4.2	10278	0.90 (0.87, 0.94)	<0.001
≥4.2	2023	0.81 (0.73, 0.90)	<0.001
TPOAb (+)^d, IU/mL				0.023
No	11366	0.90 (0.87, 0.94)	<0.001
Yes	436	0.67 (0.51, 0.88)	0.005
TgAb (+)^e, IU/mL				0.470
No	11213	0.90 (0.86, 0.93)	<0.001
Yes	354	0.95 (0.75, 1.20)	0.663

^aAdjusted for age, sex, educational status, smoking status, type of salt used, family history of thyroid diseases, systolic pressure, body mass index, and waist circumference. ^bBMI category according to the Ministry of Health of the People’s Republic of China classification: underweight (<18.5 kg/m²), normal weight (18.5 to <24 kg/m²), overweight (24 to <28 kg/m²), and obese (≥28 kg/m²). ^cTSH category: below reference range (<0.27 mIU/L), reference range (0.27 to <4.2 mIU/L), and above reference range (>4.2 mIU/L). ^dTPOAb (+): no () and yes (). ^eTgAb (+): no () and yes ().