- Low-normal levels of free triiodothyronine (FT3) and free thyroxine (FT4) are associated with incidence of anemia and annual changes in hemoglobin.
Why this matters
- This is the first study to directly evaluate the effects of thyroid hormone levels on anemia risk in a euthyroid population.
- The incidence rate of anemia was 14/1000 person-years during follow-up.
- Levels of FT3 and FT4 were inversely associated with anemia incidence (HR, 0.70 [P<.01 hr per pmol change respectively style="list-style-type:circle;">
- Thyroid-stimulating hormone (TSH) levels were not significantly associated (HR, 1.19; P=.14).
- 12,310 participants with euthyroid status were analyzed for thyroid hormone levels and incidence of anemia during approximately 5 years of follow-up (mean, 3.1 years).
- Funding: National Natural Science Foundation of China.
- Observational study design.
- Relationship between thyroid status and iodine intake not analyzed.