Abstract

PIP: The information presented in this article is offered as a guide to government agencies and public health personnel on the detection of endemic goiter and cretinism, the assessment of its severity, and the initiation and monitoring of preventive programs under various field conditions. The definition of endemic goiter is arbitrary and statistical. Enlargement of the thyroid gland is found in all communities. Any definition of endemic goiter implies a scale of measurement. In general endemic goiter would be considered to exist when more than 5% of an adolescent or preadolescent group have grade 1 goiter or when more than 30% are assigned to grade Ob or above. The following classification scheme has been found satisfactory by many observers in assessing the prevalence of abnormal thyroids: grade Oa, thyroid not palpable, or if palpable not larger than normal; grade Ob, thyroid distinctly palpable but usually not visible with the head in a normal or raised position; grade 1, thyroid easily palpable and visible with the head in a normal position; grade 3, goiter visible at a distance; and grade 4, monstrous goiters. The diagnosis of endemic cretinism can only be made in a population suffering from moderately severe to severe endemic goiter. Individuals who have the classic clinical attributes of this syndrome will not be encountered unless 20% of the population has a thyroid enlargement of grade 1 or above. Only a fraction of the total number of retarded persons in regions of severe endemic goiter conform to the textbook description of the cretin. Most investigators maintain the opinion that the primary etiological factor is iodine deficiency. The thyroid enlarges as a result of this deficiency, and with chronic stimulation it becomes nodular in the course of time. If the iodine deficiency is sufficiently severe, hypothyroidism may result. The cause or causes of endemic cretinism are less clear. It is the consensus that endemic cretinism occurs when the fetus receives insufficient iodine. The introduction in endemic goiter regions of iodized salt or other prophylactic agents has invariably been successful in markedly reducing the incidence of clinically significant goiter. A 5% incidence of grade 1 goiter in preschool or periadolescent schoolchildren or a 30% incidence of goiter in the general population would warrant the development of a prophylactic program; the presence in the population of 1% of persons who could be classified as cretins would demand early and urgent action. Methods of prevention and program implementation are reviewed.