Researchers looked at thyroid nodules and cancers in people who had autopsies at a hospital in Mexico City. They studied 487 autopsies to see how common thyroid nodular disease, papillary thyroid carcinoma, and a type called NIFTP were. They also checked if salt iodination rules, which changed in 2004, were linked to more nodules.
The study found that 55% of the autopsies showed thyroid nodular disease, meaning nodules were very common. About 9.4% had papillary thyroid carcinoma, and 1.5% had NIFTP. When comparing before and after 2004, there was no increase in nodules tied to salt iodination rules, with a p-value of 0.969 indicating no association.
This was an observational study using autopsies, so it only shows what was found in these cases and cannot explain why nodules happened. No safety concerns were reported, but the study is limited because it was retrospective and done in one city. Readers should know this research helps understand nodule prevalence but does not change medical advice or prove salt iodination causes nodules.