As iodine has been in salt to prevent the occurence of goitre, an iodine deficiency since early in the 20th century your comment does not address my 1960s. You obviously do not know that the contraceptive pill, even in women with normal thyroid function, reduces the production of T4 thyroid hormone. Hence my comments regarding age, residency and gender of the workmates.
p.s. I have to take T3 (thyroxine), not because of any iodine deficiency, but because of the most common auto-immune disease. It was detected by thyroid function tests (T3, T4 and thyroid stimulating hormone levels plus thyroid auto-antibodies). Additional iodine has no effect.