Outcome measures
Hypothyroxinemia, defined as 0.27≤TSH≤4.2 mU/L and FT4<12.00 pmol/L, was the primary outcome of this study. Secondary outcomes included in this study were: The levels of TSH and thyroid hormones, subclinical hypothyroidism (TSH>4.2 mU/L and 12.00≤free T4≤22.00 pmol/L), and overt hypothyroidism (TSH>4.2 mU/L and free T4<12.00 pmol/L).