Hypothyroidism due to iodine deficiency is the most common endocrine disorder worldwide because iodine is essential for thyroid hormone synthesis. In regions with iodine deficiency, decreased hormone production leads to hypothyroidism and goiter formation. This condition is highly prevalent in areas lacking iodized salt, affecting large populations. Early recognition and iodine supplementation are critical for prevention. Other endocrine disorders, such as Type 1 diabetes or Cushing’s syndrome, have lower prevalence globally. Thus, iodine deficiency hypothyroidism remains the leading cause in terms of global public health impact.

Reference: Harrison's Principles of Internal Medicine, J. Larry Jameson, 20th Edition.