Normal FT3:FT4 thyroid hormone ratios in large populations

A normal ratio of Free T3 (FT3) to Free T4 (FT4) thyroid hormones appears to be a basic principle in thyroid hormone economy when no thyroid hormone dosing and no disease interfere. In this post, I provide graphs, quotations, and discussions from Gullo, Strich, and Anderson as I present their FT3:FT4 ratio results, and I rely on science to present the mechanisms by which the ratio is adjusted in relationship to TSH in people not dosing thyroid hormones. Comparing across these 3 different studies, you’ll see how amazingly consistent population average FT3:FT4 ratios are among people with healthy thyroid glands …

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Prevalence rates for 10 chronic disorders at various FT4, TSH and FT3 levels

Which FT3, FT4 and TSH levels have the highest and lowest prevalence rates for 10 common health disorders? Hypertension Hyperlipidemia (high cholesterol) Depression Diabetes Coronary artery disease Heart failure Atrial fibrillation Peripheral vascular disease Renal failure (kidney failure) Dementia Is high-normal TSH and low FT3 associated with one condition, while high-normal FT4 and low or high TSH strongly associated with another condition? Or do they all have a generally similar pattern of strong disease associations with certain thyroid hormone levels? Anderson et al, 2020 collected data from the medical charts of 174,914 adults from 1999 to 2018 and associated their …

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