Table 3.

Results of multivariate analysis.

	All patients		Without levothyroxine therapy		With levothyroxine therapy
	OR (95% CI)	P	OR (95% CI)	P	OR (95% CI)	P
Positive anti-TPO	2.21 (1.14–4.28)	0.018	2.28 (1.01–5.12)	0.047	1.91 (0.59–6.21)	0.281
Ultrasound signs of Hashimoto's thyroiditis	1.13 (0.57–2.24)	0.74	1.30 (0.55–3.06)	0.552	0.86 (0.25–2.91)	0.810
Levothyroxine therapy	0.69 (0.36–1.33)	0.27	—	—	—	—
TSH <0.5 mIU/l	0.41 (0.19–0.88)	0.02	0.30 (0.12–0.75)	0.010	1.09 (0.23–5.16)	0.914
Thyroid volume > 75th percentile (18 ml)	1.21 (0.65–2.24)	0.56	1.51 (0.77–2.96)	0.234	0.30 (0.03–2.72)	0.282

TSH: thyroid-stimulating hormone; anti-TPO: antibodies against thyroid peroxidase; anti-Tg: antithyroglobulin antibody. Antibodies against thyroglobulin were excluded from the multivariate regression analysis due to missing data.