Causes of Multinodular Nontoxic Goiter

Environmental and Nutritional Factors

Iodine deficiency affects 500-600 million people worldwide and greatly enhances the incidence of multinodular goiter, with severe deficiency causing goiter and hypothyroidism due to increased thyroid activity to maximize iodine uptake and recycling, and also increasing the risk of developing autonomous thyroid nodules that become unresponsive to TSH control, according to the Clinical Nutrition guideline society 1
Iron deficiency impairs thyroid metabolism and contributes to goiter development, as stated by the Clinical Nutrition guideline society 1
Selenium deficiency affects thyroid function as deiodination of T4 to T3 depends on Type 1 5'-deiodinase, a selenoenzyme, as reported by the Clinical Nutrition guideline society 1

Female sex is a significant risk factor for multinodular goiter, being more common in women, particularly in their fifth and sixth decades, as noted by the Journal of the American College of Radiology guideline society 2
Advancing age increases goiter incidence, with typical development occurring over many years, as stated by the Journal of the American College of Radiology guideline society 2