Table 3. Multivariate analysis by logistic regression (enter method) to evaluate factors independently associated with NSSPM occurrence in DTC patients.

Variable	Coefficient	S.E.	P value
Age at DTC diagnosis (years)	0.04	0.17	0.04*
Gender (Female)	-0.56	0.68	0.41
Histological type (Papillary)	0.03	0.60	0.97
RAI-131	0.56	0.59	0.35

DTC: differentiated thyroid carcinoma; NSSPM: non-synchronous second primary malignancy; RAI-131: I¹³¹ radioactive iodine treatment; S.E.: standard error.

* Statistically significant p < 0.05.