My ten year old was recently diagnosed with autoimmune hypothyroidism. Her TSH level was 33. Her older sister was diagnosed with type 1 diabetes at age nine and autoimmune hypothyroidism at age 12. Since my ten year old has been diagnosed with the thyroid disorder before diabetes, how likely is she to get type 1 diabetes? I have read much about children developing diabetes and then thyroid disorders, but I have not read much about the reverse. There is a strong family background as I have hypothyroidism and my father has vitilgo.

Great question. You are correct that diabetes and thyroid problems often co-exist – about 20% and, perhaps as high as 40%, in some series, depending upon which antibodies are screened. Vitiligo, celiac disease, adrenal insufficiency (Addison’s), pernicious anemia and variants (gastroparietal antibodies) are also more common and more common in families as in yours. But, it is quite rare to start with thyroid and then diabetes, for reasons totally unknown. In either case, I would screen for all these antibodies in your child were this my patient and periodically repeat such screening several times, perhaps annually, even with no symptoms, to see what changes (or doesn’t) over time.

SB