Predicting Thyroid Dysfunction When Baseline TSH Is “Normal”

In women, risk for hypothyroidism increases substantially when TSH level is 2.5 to 4.5 mIU/L.

Thyroid-stimulating hormone (TSH) levels near the upper and lower limits of the designated normal range may predict above-average risk for hypothyroidism and hyperthyroidism, respectively. In a population-based Norwegian study, researchers identified 15,000 euthyroid adults (age range of most, 40–70) who had serum TSH levels between 0.2 and 4.5 mIU/L. During a mean follow-up of 11 years, these findings emerged:

In women, the eventual incidence of overt hypothyroidism was low (1%–3%) when baseline TSH was <2.5 mIU/L. Above this threshold, hypothyroidism eventually developed in 8%, 14%, and 32% of those with baseline TSH levels of 2.5–2.9, 3.0–3.9, and 4.0–4.5 mIU/L, respectively.
In men, the eventual incidence of overt hypothyroidism was <2% w…

Reviewing Author

Allan S. Brett, MD

Disclosures

Nothing to disclose

Allan S. Brett, MD

Disclosures

Nothing to disclose