Table 3.

Effects of thyroid dose and tumor size on extrathyroidal extension.

	OR (95% CI)	p-value	AICa		OR (95% CI)	p-value	AIC
POC and its components				Tumor size
Non-adjusted					Non-adjusted
POC	1.010 (1.000-1.020)	0.046	372.749	Tumor size, mm	1.215 (1.042-1.417)	0.013	370.264
Sex	1.721 (0.954-3.105)	0.071	373.517
Age at exposure, years	0.966 (0.919-1.016)	0.183	374.819
Latency period, years	1.019 (0.968-1.073)	0.473	376.073
Age at operation, years	0.993 (0.960-1.027)	0.674	376.425
Thyroid dose, mGy (log)	1.266 (1.013-1.583)	0.038	372.406
	Model 1A		374.353		Model 1B		369.399
Sex	1.701 (0.930-3.110)	0.085		Sex	1.779 (0.972-3.256)	0.062
Age at exposure, years	0.992 (0.933-1.055)	0.795		Age at exposure, years	0.961 (0.913-1.011)	0.122
Latency, years	1.033 (0.981-1.088)	0.214		Latency period, years	1.034 (0.981-2.091)	0.21
Thyroid dose, mGy (log)	1.248 (0.942-1.653)	0.123		Tumor size, mm	1.239 (1.060-1.450)	0.007
	Model 2A		373.399		Model 2B		371.243
Sex	1.636 (0.899-2.978)	0.107		Sex	1.699 (0.934-3.090)	0.082
Age at operation, years	1.016 (0.977-1.057)	0.424		Age at operation, years	0.996 (0.962-1.031)	0.829
Thyroid dose, mGy (log)	1.313 (1.005-1.714)	0.046		Tumor size, mm	1.214 (1.040-1.417)	0.014
Models combining POC or its components and tumor size
	Model 3A		369.003		Model 3B
Sex	1.705 (0.926-3.138)	0.086			Could not be fitted
Age at exposure, years	0.988 (0.928-1.052)	0.703		Sex
Latency period, years	1.042 (0.988-1.099)	0.13		Age at operation, years
Thyroid dose, mGy (log)	1.251 (0.938-1.668)	0.128		Thyroid dose, mGy (log)
Tumor size, mm	1.240 (1.059-1.452)	0.008		Tumor size, mm

^aAkaike information criterion.Numbers in bold indicate statistical significance.