Table 2.

Summary of published human studies reporting thyroid-related findings in radiation-exposed populations.

Study type	Population studied	Type of radiation exposure	Thyroid-related findings	Observations reported in the literature
Narrative and systematic reviews (11–13)	Healthcare and medical radiation workers	Chronic occupational exposure	Thyroid nodules, functional alterations	Long-term radiation exposure discussed in literature as a possible factor that may affect thyroid structure and function
Meta-analyses (3, 26)	Occupationally exposed adults	External ionizing radiation	Thyroid cancer risk	Reported associations between increased thyroid cancer risk with cumulative radiation dose
Cohort and pooled studies (7–9)	Medical radiation workers and exposed populations	Repeated diagnostic or occupational exposure	Structural and malignant thyroid changes	Reported risk estimates vary according to dose, duration, and age at exposure
Dental exposure studies (4, 6)	Dental healthcare workers	Low-dose occupational exposure	Limited direct data	Available evidence remains limited; further focused research is needed