Have you ever gone to the doctor with all the symptoms of hypothyroidism and are told your labs are “normal?” What if they were technically normal but not exactly optimal? That’s called sub-clinical hypothyroidism and it too can cause a whole host of problems.
When your thyroid is sub-clinical, it means it is able to function but not at its best. Imagine you after 8 hours of good solid sleep versus 4 hours of interrupted sleep. You’re still considered normal, just not optimal.
Women with lower thyroid (but not all out low) tend to have symptoms of fatigue, weight gain, dry hair and skin, hair thinning or loss, cracked/weak nails, constipation, and muscle and joint pains. Additionally, cholesterol markers start to turn for the worse while triglycerides start to clime. Heart contractility decreases and the risk for atherosclerosis increases. There is increased risk for depression, miscarriage, menstrual irregularities such as longer days between periods, long periods or heavy periods.
All these symptoms are the same for full-blow hypothyroidism, just not as severe. For example, your cholesterol might be elevated, but not as elevated as if you were fully hypothyroid. Your hair loss might be minimal compared to losing large clumps.
Either way, none of these symptoms are fun and should not be ignored by your healthcare practitioner. When asking for thyroid testing, request that you get the basic screening test, Thyroid Stimulating Hormone (TSH) along with the Free T4, Free T3, and check for autoimmune thyroid such as Thyroid Peroxidase Antibody and Thyroglobulin Antibody.
The generally accepted range for TSH is 0.5 – 5.0mIU/ml, however in 2003, the American Association of Clinical Endocrinologists put out a statement that any TSH above 3.0 mIU/ml should be addressed. Depending on how your practitioner treats, they may not know about this statement or not agree with it.
The National Academy of Clinical Biochemistry believes optimal TSH levels should be between 0.4-2.5 mIU/ml however most labs still report an upper level of 5.0 mIU/ml.
Bottom line is to ask for the actual numbers once you get your thyroid tests back (don’t settle for ‘low,’ ‘high,’ or ‘normal’) and if you are symptomatic, make sure it is being addressed, regardless of the numbers. Finally, if you do fall above the 2.5-3.0mIU/ml range, discuss treatment options with your practitioner.
References:
1) American Association of Clinical Endocrinologists. "January is Thyroid Awareness Month~ 2003 Campaign Encourages Awareness of Mild Thyroid Failure, Importance of Routine Testing." January 2003.
2) Surks, et. al. "Controversy in Clinical Endocrinology: The Thyrotropin Reference Range Should Remain Unchanged," Journal of Clinical Endocrinology and Metabolism 90(9)/5489-5496
3) Wartofsky & Dickey, "Controversy in Clinical Endocrinology: The Evidence for a Narrower Thyrotropin Reference Range is Compelling," Journal of Clinical Endocrinology and Metabolism 90(9)/5483-5488