<prompt> What is the most common cause of hypothyroidism world-wide?Hashimoto thyroiditisSubacute thyroiditisSilent thyroiditisIodine deficiency  <response>: Most common cause of hypothyroidism worldwide is IODINE DEFICIENCY In case of Iodine sufficiency most common cause of hypothyroidism : Autoimmune disease Hashimoto Thyroiditis and iatrogenic. 