Table 2.

Associations of serum TSH, fT3, and fT4 levels with glycaemic markers in the pooled population not taking l-thyroxin (n  = 3719).

	TSH, mIU/L, β (95% CI)	fT3, mIU/L, β (95% CI)	fT4, mIU/L, β (95% CI)
Linear regression: β (95% CI)
Fasting glucose, mmol/L	−0.001 (−0.014, 0.013)	NLa	0.012 (0.002, 0.023)a
2-h postload glucose, mmol/L	0.013 (−0.025, 0.052)	NL (P  = 0.075)	0.043 (0.013, 0.074)a
Fasting insulin, mU/L	−0.023 (−0.151, 0.106)	NLa	−0.026 (−0.125, 0.072)
2-h postload insulin, mU/L	1.079 (0.026, 2.132)a	NLa	0.185 (−0.628, 0.998)
Homeostatis model assessment (HOMA-IR)	−0.006 (−0.045, 0.033)	NLa	0.006 (−0.024, 0.036)
Insulin sensitivity index (ISI)	0.001 (−0.103, 0.105)	NLa	−0.020 (−0.100, 0.060)

Analyses are adjusted for age, sex, smoking status, BMI, and study.

^a P  < 0.05.

NL, non-linear relationship (see Fig. 1).