Nutrition and iodine versus genetic factors in endemic goiter.

Consanguinity has been considered to be the major factor responsible for the high incidence of goiter in the area of Las Hurdes in Spain. However, iodine deficiency was later found to be severe enough to account for endemic goiter, and the presence of cretins in this area. Children from very similar family and socioeconomic backgrounds were found to be on three different nutritional programs, depending on the schools they were attending, and it appeared of interest to determine the effect of nutrition on the goiter incidence in children from the same population. Total iodine, nitrogen and creatinine concentrations were measured in casual urine samples. All three were found to change in parallel in the different subpopulations. They were low in schoolchildren receiving most of their meals at home. Such meals were composed of locally grown food. They were normal in children living in a boarding school, where all of the food is provided from outside the area. They were intermediate in children from a day care center, who received only some meals from an outside source. In the boarding school, goiter incidence was 21%, as opposed to 87% for schoolchildren fed at home. Such results indicate that in this area consanguinity plays a minor role, if any, in the high incidence of goiter.