In healthy people, high serum antithyroid
antibody concentrations are associated with high serum thyrotropin
concentrations and thyroid enlargement
(July 2005)
The background of the study. High serum concentrations
of antithyroid peroxidase (anti-TPO) or antithyroglobulin (anti-Tg)
antibodies are the hallmark of autoimmune thyroid disease. Thyroid
function may be normal or low, and the thyroid gland may be enlarged
or small. The relationships between thyroid antibodies, size, and
function were studied in a large group of people in Denmark.
How the study was done. The group consisted of
4168 people living in two regions of the country. Thyroid volume
was measured by ultrasonography (normal, 6.6 to 14.9 ml). Serum
thyrotropin (TSH) (normal, 0.4 to 3.6 mU/L), anti-TPO antibodies,
and anti-Tg antibodies also were measured.
The results of the study. The thyroid gland was
small in 5 percent of the subjects, normal in 60 percent, and large
in 35 percent. Serum TSH concentrations were low in 5 percent, normal
in 91 percent, and high in 4 percent.
Overall, serum anti-TPO, anti-Tg antibodies, or both were detected
in 19 percent of the subjects. One or both antibodies were detected
in 18 percent of those with low serum TSH concentrations, 17 percent
of those with normal concentrations, and 65 percent of those with
high concentrations.
Among the subjects with high serum TSH concentrations, one or both
serum antibodies were detected in 91 percent of those who had a
large thyroid, 62 percent of those with a normal-sized thyroid,
and 44 percent of those with a small thyroid. In contrast, among
the subjects with normal or low serum TSH concentrations, there
was no relationship between serum anti-TPO or anti-Tg antibodies
and thyroid volume.
The conclusions of the study. Among healthy subjects,
the presence of serum antithyroid antibodies is associated with
increasing serum TSH concentrations, and with thyroid enlargement
in those with high serum TSH concentrations.
The original article. Bulow Pedersen I, Laurberg
P, Knudsen N, Jorgensen T, Perrild H, Ovesen L, Rasmussen LB. A
population study of the association between thyroid autoantibodies
in serum and abnormalities in thyroid function and structure. Clin
Endocrinol (Oxf) 2005;62:713-20.
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