The manuscript presents an observational study assessing the risk of developing type 1 diabetes in individuals with celiac disease, hyperthyroidism, and hypothyroidism.

The topic and the findings are not novel.

Nevertheless, the large population might provide solid confirmatory data to reinforce what is already known about the topic, eventually supporting recommendations for early screening and monitoring of individuals with autoimmune diseases for the development of T1D.

Besides novelty, another main concern about the study relies on the possibility that the authors included non-autoimmune causes of hyperthyroidism and hypothyroidism.

Although the authors acknowledge this as a limitation of the study, they also use throughout the paper "other autoimmune diseases", which is an evident mistake.

In my opinion, the presence of this limitation does not allow the use of the general wording "other autoimmune diseases" and the whole manuscript (especially the abstract, the introduction and the discussion paragraph) should be re-written considering that results are not solely related to other autoimmune diseases, but they are severely confounded by the presence of other causes of hyperthyroidism and of hypothyroidism (especially for hyperthyroidism, which might account, according to the data presented in the manuscript, for up to 40% of non-autoimmune causes).

The title of the manuscript better reflects the results, and the authors are strongly invited to adhere to the title also in the other sections of the main text and in the abstract

• because of the impossibility of excluding non-autoimmune causes of thyroid diseases, I would have included in the study other autoimmune disorders with a more precise diagnostic code (such as vitiligo, rheumatoid arthritis, atrophic gastritis, etc.). May these data be added?

• The discussion might include a more explicit acknowledgment of the potential for residual confounding due to imbalanced variables

Thank you, I have no further comments