Summary and conclusion
	Multinodular goitre and neoplastic and autoimmune goitre are the three main types of non endemic goitre. Types may overlap in individual patients. Epidemiological data demonstrate that development of a multinodular goitre is highly dependent on the iodine intake and that TSH stimulation is of less importance. The basic driving force during goitrogenesis seems to be the iodostate which autoregulates the thyroid. Somehow a more or less irreversibel polyfocal polyclonal process takes place in the thyroid gland with replication of highly heterogeneous follicles. The frequency of growth promoting mutations is enhanced leading to scattered monoclonal nodules. An abnormal low iodinating activity in the sick gland may self-perpetuate the process. The main preventive action is a proper level of population iodine intake and a decrease in the intake of goitrogens such as tobacco smoke. However despite these measures, a residual prevalence of multinodular goitre will remain in which a genetic etiology may play a role. Preventive measures may also be helpfull as treatment in the early stages of the disease, whereas radioiodine therapy and in some cases surgery is necessary if treatment is needed in more advanced cases. A major complication of multinodular goitre is clinical and subclinical hyperthyroidism which occur with high prevalence in the elderly in low iodine intake areas.