Thyroid function and risk of anemia: A multivariable-adjusted and Mendelian randomization analysis in the UK Biobank
Journal of Clinical Endocrinology and Metabolism — van Vliet NA, Kamphuis AEP, den Elzen WPJ, et al. | September 15, 2021
While a self-reported clinical diagnosis of hypothyroidism was linked to a greater risk of anemia [defined as hemoglobin level of <13 g/dL in men and <12 g/dL in women], no evidence of a causal relationship with variations in thyroid function within the euthyroid range was found. Thyroid hormone intracellular regulation, on the other hand, may play a function in the development of anemia.
It was a cross-sectional and Mendelian Randomization study.
The sample consisted of 445,482 candidates, mean age of 56.77 years (SD 8.0) and 54.2% were women.
Self-reported clinical diagnoses of hypo- and hyperthyroidism were related to a greater risk of anemia in cross-sectional logistic regression studies, however with large confidence intervals for hyperthyroidism.
They found no link between greater or lower genetically influenced thyrotropin and anemia, nor between higher or lower genetically influenced free thyroxine and anemia.
Individuals with genetic variants in the DIO3OS gene, which is involved in the intracellular regulation of thyroid hormones, were at a greater risk of anemia; no association was seen with variants in the DIO1 or DIO2 genes.