@coby - I think we mustn't get going down rabbit holes too quickly here. Thyroid malfunction is incredibly common - in something like 2% of the adult population, rising yo c5% in those over 50(if my recall is accurate). Obviously, not all of those with thyroid malfunctions will develop diabetes, nor will all those with diabetes develop thyroid malfunctions.
Where there us a definite link is in auto-immune thyroiditis (Hashimoto's Disease), and diabetes, due to the auto-immune nature. I deliberately haven't differentiated the types of diabetes as although T2 isn't wholly AI, there are many folks with AI conditions also living with T2. For me T2 is a portfolio condition, with many common bedfellows and passengers on the journey.
I developed an atypical thyroid malfunction a few years after my T2 diagnosis - my main symptom was always feeling very, very cold. My family is littered with AI disease, so the Endo ordered up a massive list of tests, looking for every condition I listed, plus a few more for good measure and sport, it seemed. At that point, I had dodged every single AI bullet.
I am treated with a combination therapy of 125mcgr Levothyroxine (T4) and 50mcgr Liothyronine (T3) per day.
Personally, I try not to go too far down these linking rabbit holes as it doesn't necessarily hold true for everyone, and we could end up living life waiting for scary things to happen, which isn't what life's for. I just try to look after myself as well as I can and hope my body will be strong for me.
Sometimes our genes are wonderful, and sometimes they conspire against us, but changing our genetic make up isn't generally under our control.