Hypothyroidism now appears to be one of the most common complications of diabetes. Fortunately, it is one of easiest conditions to manage. All it requires is taking one little pill the first thing every morning to make up for the thyroid hormone that we lack.
Checking our TSH level is the usual way our doctors have to find out if we have hypothyroidism. Our pituitary glands make TSH, short for thyroid stimulating hormone.
How common hypothyroidism is depends on how we define a normal TSH level. Currently, most countries set the reference range at 0.40 to 4.5 mIU/l. But some organizations and many new studies suggest that a level of 4.5 is far too high to be considered normal.
The American Association of Clinical Endocrinologists considers 0.3–3.0 to be the normal range. But the National Academy of Clinical Biochemistry guidelines indicate that more than 95 percent of normal people have TSH levels below 2.5.
The HUNT study from Norway reported in a 2008 issue of The Archives of Internal Medicine that they used the TSH test to measure the thyroid function of 17,000 women and 8,000 men with no known thyroid or heart disease. All the people in the study had a “normal” TSH level of 0.5 to 3.5. The people in the lowest TSH group, those with a level of 0.5 to 1.4, had 70 percent less heart disease than those in the highest TSH group, who had a level of 2.5 to 3.5.