If you have type 2 diabetes, you should receive a screening for thyroid abnormalities, according to researchers at the American Association of Clinical Endocrinologists (AACE) 20th Annual Meeting and Clinical Congress. The recommendation came after a new study involving over 5,000 people found the prevalence of hypothyroidism to be nearly 6 percent among people with type 2 diabetes, compared to just under 2 percent in those without.
Hypothyroidism is a well-recognized risk of type 1 diabetes, but this has generally not been extended to type 2 diabetes as well -- until now.
What Does Your Thyroid Function Have to do With Diabetes?
Both thyroid disorders and diabetes involve a dysfunction of the endocrine system. Type 1 diabetes and the most common cause of hypothyroidism -- Hashimoto's disease -- are both autoimmune diseases, and having one autoimmune disease increases your risk of developing another.
With type 2 diabetes, coexisting hypothyroidism may increase your risk of heart problems, and the researchers noted that early identification of both conditions could improve heart function, blood pressure and lipid profile. 
Thyroid hormones also influence glucose homeostasis, including impacting circulating insulin levels, intestinal absorption and uptake of glucose into fat and muscle tissues. 
Even Subclinical Thyroid Disorder May be Associated With Diabetes
People with hypothyroidism often struggle with insulin resistance. This is true even at the sub-clinical level. How do you know if your thyroid is functioning at a sub-clinical level?
Oftentimes, you don't.
This condition is typically diagnosed when levels of your thyroid hormones are normal but your thyroid-stimulating hormone (TSH) is increased. This is generally a sign that your pituitary gland is working extra hard to keep your thyroid hormone levels up in the normal range. In time, and if left untreated, your TSH levels may continue to increase until your thyroid gland stops responding, and your sub-clinical hypothyroidism turns into full-blown hypothyroidism.
It's a tricky situation because sub-clinical hypothyroidism may cause no symptoms at all, or it may lead to fatigue, memory problems, weight gain, dry skin, constipation and a range of other various problems that may seem completely unconnected. Again, this often undiagnosed and misdiagnosed condition is also associated with insulin resistance, which typically occurs prior to type 2 diabetes.
As researchers wrote in Clinical Diabetes: 
"Thyroid dysfunction is common in diabetic patients and can produce significant metabolic disturbances. Therefore, regular screening for thyroid abnormalities in all diabetic patients will allow early treatment of sub-clinical thyroid dysfunction."
Like sub-clinical hypothyroidism, you can be insulin resistant for years before developing full-blown disease, and often a diagnosis of type 2 diabetes is a person's first sign that they are in fact insulin resistant.
Because cases of sub-clinical thyroid disease are often overlooked but may increase health risks for a number of people with co-existing diabetes or insulin resistance (as well as those without), researchers in the British Journal of Diabetes and Vascular Disease recommended "individualization of therapy" as the best solution.
What's the Bottom Line?
If you currently have type 2 diabetes, you should be aware of the connection to thyroid disorders like hypothyroidism and sub-clinical hypothyroidism. At the sub-clinical level, many have no symptoms at all, and others are unaware that their fatigue, memory problems and other seemingly unrelated symptoms are due to a thyroid issue.
You may need to ask your physician to have this checked, as it is not yet part of the standard of care typically provided for people with type 2 diabetes. But, even if you've had your thyroid levels tested and the lab results came back normal, it's still possible to have a low-functioning thyroid. In fact, the condition is often completely missed due to inadequate testing and a general lack of understanding of the complexities of thyroid function in the conventional medical community.
There is some debate over whether or not sub-clinical hypothyroidism needs to be treated at all, and to this I would stress absolutely. At the very least, sub-clinical hypothyroidism can contribute to insulin resistance as well as increase your risk of cardiovascular events if you have type 2 diabetes.
Further, many in this early stage of thyroid imbalance will go on to develop full-blown hypothyroidism if action is not taken... and will miss out on the vitality and energy they deserve in life.
At least 15 million Americans are thought to suffer from sub-clinical hypothyroidism that may or may not be related to diabetes. Fortunately, dietary approaches and other lifestyle changes can help bring your thyroid function back into the normal ranges, as well as help you to prevent, control and even reverse type 2 diabetes. The guidance of a holistic health care practitioner familiar with both thyroid disorders and diabetes is highly recommended to help you formulate an effective lifestyle plan and stick with it.
1. DocGuide.com April 18, 2011
2. British Journal of Diabetes and Vascular Disease. 2010;10(4):172-177.
3. Clinical Diabetes VOL. 18 NO. 1 Winter 2000