Meta-analysis of the effects of low-dose ionizing radiation on the thyroid of medical radiation workers / 中华放射医学与防护杂志

ABSTRACT

Objective:To assess the effects of low-dose ionizing radiation on the thyroid of medical radiation workers.Methods:Based on the inclusion and exclusion criteria, 27 articles, involving 22 937 individuals, were screened finally from relevant literature published from 1996 to 2022. Meta-analysis was carried out using Stata 16.0 for serum levels of triiodothyronine (T 3), free triiodothyronine (FT 3), thyroid hormone (T 4), free thyroid hormone (FT 4), thyrotropin-stimulating hormone (TSH) and thyroid nodule rates. As well, subgroup analysis were carried out of thyroid function in different types of radiation workers. Results:The standardized mean difference (SMD) at T 3 and T 4 levels for radiation workers was -0.19 (-0.37, -0.01) and -0.34 (-0.38, -0.30), lower than that of control group ( Z=2.07, -16.06, P<0.05). The SMD at FT 4 levels for radiation workers was 0.22 (0.06, 0.39), higher than control group ( Z=2.61, P<0.05). The relative risk of thyroid nodules in radiation workers was 1.47 (1.19, 1.82), higher than that of control group ( Z=-3.58, P<0.05). The analysis result for subgroup showed that the SMD for T 3, T 4 and TSH levels in the interventional radiology workers were -0.29 (-0.51, -0.07), -0.31 (-0.47, -0.15) and -0.43 (-0.73, -0.13) ( Z=-2.55, -3.86, -2.82, P<0.05), respectively, and the SMD for T 4 levels in the nuclear medicine workers was -0.26 (-0.45, -0.07), which meaned a reduced risk compared to the control group ( Z=-2.70, P<0.05). Conclusions:Long-term low doses of ionising radiation may have adverse effects on thyroid hormone and thyroid nodule in radiation workers, particularly in interventional radiology workers, and attention should be focused on their radiation protection.