TG and thyroiditis: We previously conducted a cross-sectional study and demonstrated that serum Tg level was affected by gender, amount of iodine intake, serum TSH level, and thyroid volume, based on the data collected from a five-year follow-up population survey in adults from both deficient and more than adequate or excessive iodine intake regions, known as “iodine induced thyroid disease (IITD) program” from 1999 to 2004 [13].