Prevalence of growth hormone deficiency in Hashimoto's thyroiditis.
BACKGROUND
Autoimmune hypophysitis can result in GH deficiency (GHD) and is associated with other autoimmune endocrine diseases like Hashimoto's thyroiditis. Recent studies suggest a high prevalence (5%) of GHD in Hashimoto's thyroiditis.


OBJECTIVE
Our objective was to establish the prevalence of GHD in patients with treated autoimmune hypothyroidism (AIH).


METHODS
We included patients with spontaneous AIH [thyroid peroxidase antibodies (TPO-Ab) >or=100 kU/liter], who were adequately treated with T(4) (TSH 0.2-5.0 mU/liter). Exclusion criteria were previous I(131) treatment, thyroid surgery, or a history of hypothalamic or pituitary disease. Patients were recruited via our outpatient clinics and via patient self-help organizations.


METHODS
We measured serum TSH, free T(4), TPO-Ab, and IGF-I. If the IGF-I concentration was below the 10th percentile of age-specific reference values, a GHRH/GH-releasing peptide (GHRP)-6 test was done. GHD was defined as a GH peak after GHRH/GHRP-6 below the 2.5th percentile of age-specific reference values.


METHODS
IGF-I concentration and GH peak after GHRH/GHRP-6 test were measured.


RESULTS
From 860 patients who applied, 322 did not satisfy inclusion criteria (157 because TPO-Ab was <100 kU/liter, 165 because TSH was <0.2 or >5.0 mU/liter), and 23 had an exclusion criterion. In the remaining study population of 515 patients (476 female, 39 male), 49 patients (9.5%) had an IGF-I concentration below the 10th percentile. These patients underwent a GHRH/GHRP-6 test. Two patients had a GH peak below the 2.5th percentile.


CONCLUSIONS
The prevalence of GHD in Dutch patients with AIH is 0.4% (two of 515).
Academic Medical Center Amsterdam, Department of Endocrinology and Metabolism, Meibergdreef 9, 1100 DD Amsterdam, The Netherlands. s.a.eskes@amc.uva.nl
Silvia A
SA
Eskes
Erik
E
Endert
Eric
E
Fliers
Wilmar M
WM
Wiersinga
D000328:Adult; D000368:Aged; D005260:Female; D013007:Growth Hormone-Releasing Hormone / Q000097:blood; D050031:Hashimoto Disease / Q000097:blood* / Q000453:epidemiology; D019382:Human Growth Hormone / Q000097:blood / Q000172:deficiency*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D009842:Oligopeptides / Q000097:blood; D018579:Patient Selection; D015995:Prevalence; D013972:Thyrotropin / Q000097:blood; D013974:Thyroxine / Q000097:blood
D009842:Oligopeptides; D019382:Human Growth Hormone; D007334:Insulin-Like Growth Factor I; C048770:glycyl-histidyl-arginyl-proline; D013972:Thyrotropin; D013007:Growth Hormone-Releasing Hormone; D013974:Thyroxine