The association between As and noncancerous thyroid disease can be explained by the mechanism proposed by a study in China in which rats exposed to NaAsO2 had increased serum TSH and decreased serum T3 and T4 levels, histological alterations in the thyroid, raised ratio of Bax/Bcl-2, and buildup of As in thyroid tissues (Fan et al., 2023). Here, BAX is linked to thyroiditis.