Diabetic neuropathy (cold or numb hands or feet) is a common sign of poor circulation in diabetes.
Low magnesium is another cause of cold hands or feet. I had this symptom with magnesium deficiency. My feet were freezing! I had severe magnesium deficiency due to a combination of insulin resistance, stress from surgery, high doses of vitamin D.
“A deficiency can occur with type 1 and type 2 diabetes, but appears to be more prevalent with type 2. This is because low levels of magnesium are associated with insulin resistance.”
I'm diagnosed with diabetes2. I wear socks in bed too.