Figure 1.

The multifactorial origin of goiter: The most important known, preventable cause of thyroid enlargement is iodine deficiency. The prevalence of goiter is directly related to iodine deficiency and tends to decrease when the iodine intake of a population is increased. The risk factors for goiter include intrinsic biological factors (which account for the five- to tenfold higher prevalence of goiter among women) as well as cigarette smoking, naturally occurring goitrogens, selenium or zinc deficiency, and emotional stress.