The risk of perchlorate and iodine on the incidence of thyroid tumors and nodular goiter: a case-control study in southeastern China

Table 5 Correlation between perchlorate and thyroid function under different iodine levels

Indicators	β	%95 CI for β	P-value
With inadequate iodine levels (n = 53)
TSH	0.020	(−0.13, 0.17)	0.799
TT3	0.013	(−0.059, 0.086)	0.721
TT4	3.80	(−0.87, 8.47)	0.118
FT3	−0.041	(−0.14, 0.059)	0.429
FT4	0.020	(−0.022, 0.062)	0.358
TPOAb	0.41	(−0.037, 0.86)	0.079
TgAb	0.14	(−0.08, 0.35)	0.226
With adequate iodine levels (n = 87)
TSH	0.19	(0.040, 0.33)	0.015
TT3	−0.013	(−0.082, 0.056)	0.715
TT4	2.46	(−2.00, 6.92)	0.283
FT3	−0.091	(− 0.19, 0.0044)	0.065
FT4	0.011	(−0.032, 0.055)	0.609
TPOAb	−0.18	(−0.55, 0.19)	0.349
TgAb	0.021	(−0.25, 0.29)	0.883
With more than adequate or excess iodine levels (n = 71)
TSH	0.029	(−0.17, 0.23)	0.774
TT3	−0.071	(−0.14, 0.0021)	0.061
TT4	−2.55	(−7.88, 2.79)	0.353
FT3	−0.12	(−0.23, − 0.0049)	0.045
FT4	0.025	(−0.015, 0.066)	0.224
TPOAb	0.10	(−0.31, 0.51)	0.620
TgAb	0.37	(0.023, 0.71)	0.041

Note: Perchlorate and iodine were corrected by urinary specific gravity (USG); Perchlorate, iodine, gender, age, BMI, smoking, and drinking were included in the model. Perchlorate, iodine, TSH, TPOAb and TgAb were natural logarithm conversion. CI confidence interval, TSH thyroid stimulating hormone, TT3 triiodothyronine; TT4 thyroxine, FT3 free triiodothyronine, FT4 free thyroxine, TPOAb thyroid peroxidase antibody, TgAb thyroglobulin antibody