I was talking to a cyber pal in Germany about Iodine and she thinks overconsumption of Iodine is a problem there. Pasting in her comments,
would appreciate yours:

"In Germany iodized salt can be/ is radioactive because they use Iodine recycled from medical applications etc.!
Additionally, apparently iodization of salt used in commercial products is mandatory (required by law) and virtually all processed products here are said to be iodised. According to the author Dagmar Braunschweig-Pauli who got very sick from this (Graves' disease) and who wrote several books about the subject of 'hyperiodisation', many people's health here as well as in Austria and Switzerland where the same rules apply, is damaged by getting too much iodine in this manner.

According to this author's research, diseases that can be caused by an oversupply of iodine include aggressivity, acne, allergies, arteriosclerosis, respiratory diseases, conjunctivitis, depressions, diabetes, heart disease, hyperactivity, impotence, headache, cancer, circulatory disorders, light allergy, Graves' disease, osteoporosis, thyroid diseases, vision disorders, tuberculosis, restless legs...
According to this author as well as readers who comment on her books on amazon.de, iodine needs vary from person to person. Since iodine is also fed here to animals (it is added to all their food by law)where it accumulates in their meat and milk, much of the iodine consumed here 'mandatorily' comes from animal products and in sensitive people leads to symptoms of too much iodine and various diseases. For example,Hashimoto's thyroiditis is strongly on the rise here and associated with high iodine intake. (And add to this the fact that iodised salt can be / is radioactive here...)

According to one German Wikipedia article (which seems not particularly biased - I know they often are), Graves' disease is associated with iodine overconsumption.

I will look into this further as priorities permit, I just thought it was interesting as another facet to the health puzzle... I assume there is no enforced iodization in your country regarding animal feed etc. so oversupply by 'forced' consumption of iodine particularly via animal products is no issue but rather the opposite, i.e. iodine deficiency..."