What are Optimal TSH Levels in Hashimoto’s Disease and Hypothyroidism?


Manage episode 262995147 series 2687172
Player FM과 저희 커뮤니티의 Dr. Nikolas Hedberg, D.C. - Functional Medicine Researcher, Dr. Nikolas Hedberg, and D.C. - Functional Medicine Researcher 콘텐츠는 모두 원 저작자에게 속하며 Player FM이 아닌 작가가 저작권을 갖습니다. 오디오는 해당 서버에서 직접 스트리밍 됩니다. 구독 버튼을 눌러 Player FM에서 업데이트 현황을 확인하세요. 혹은 다른 팟캐스트 앱에서 URL을 불러오세요.
TSH is the current gold standard for diagnosis of hypothyroidism but are the current TSH levels optimal and how do they relate to Hashimoto’s disease? An excellent paper out of China entitled, “Using Hashimoto thyroiditis as gold standard to determine the upper limit value of thyroid stimulating hormone in a Chinese cohort” has shed some light on this important question which looked at the upper limit of TSH levels in relation to Hashimoto’s disease and hypothyroidism. The authors begin by stating that subclinical hypothyroidism is characterized by “normal” T4, T3, Free T4, and Free T3 with an elevated TSH. And these patients have an increased risk of cholesterol abnormalities, heart disease, mental illness, and pregnancy complications even though their symptoms are relatively mild. The current upper limit for “normal” TSH is 4.0-5.0 mU/L but some authors have stated that it should be 2.5-3.0 mU/L. The National Academy of Clinical Biochemists (NACB) guidelines have stated that 95% of normal individuals have a TSH below 2.5 mU/L which tends to be the upper limit value used by functional medicine practitioners. How was the study done? A hefty study group of 2,856 individuals aged 20-60 were examined and tested for the study. Blood tests included: Free T3 Free T4 TSH Thyroid peroxidase antibodies Thyroglobulin antibody Total cholesterol Triglycerides LDL cholesterol Fasting glucose Uric acid ALT (liver enzyme) Creatinine Carbon dioxide combining power Participants were diagnosed with Hashimoto’s disease based on the presence of thyroid antibodies and abnormalities on a thyroid ultrasound. They excluded individuals who were taking thyroid medication, pregnant, history of thyroid operations, or a history of autoimmune disease. The average age was 36 with 75% being women and 25% men. What were the study results? 7% of the subjects were diagnosed with Hashimoto’s disease with 14 men and 173 females which syncs with previous data that Hashimoto’s disease is more prevalent in women. Those diagnosed with Hashimoto’s disease did not show any differences in age, body mass index, waist to hip ratio, blood pressure, liver tests, blood glucose, or cholesterol. Creatinine and uric acid levels were lower in the Hashimoto’s disease group but his is due to the higher prevalence of women in this group who tend to have lower levels of these markers compared to men. The proportion of participants with Hashimoto’s disease was 4% when the TSH was below 2.6 compared to 14% when the TSH was above 2.6. They grouped the participants into three categories of 2.6, 2.9 and 4.5 TSH cutoff values and found some interesting results. TSH values of 2.6 and 2.9 cutoff values were able to detect more people with abnormal triglycerides and LDL cholesterol. The authors did find that a TSH value of 4.2 to the be the upper limit of normal in their analysis. However, the authors used a “prevalence of Hashimoto’s thyroiditis” factor to determine the upper limit of TSH and found a range of 2.6-2.9 to be more appropriate. They state that this correlates with the National Academy of Clinical Biochemists findings of a 2.5 upper limit for TSH levels. The authors reference multiple studies linking TSH levels in the upper limit to high blood pressure, high cholesterol, and a higher Framingham score which is a marker for cardiovascular disease risk. These include: Age- and Race-Based Serum Thyrotropin Reference Limits Associations of TSH levels within the reference range with future blood pressure and lipid concentrations: 11-year follow-up of the HUNT study Serum TSH related to measures of body mass: longitudinal data from the HUNT Study, Norway Thyroid-Stimulating Hormone Levels within the Reference Range Are Associated with Serum Lipid Profiles Independent of Thyroid Hormones Author conclusions “This study shows a high prevalence of Hashimoto’s thyroiditis occurred among indiv...

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