Neurocognitive and Metabolic Effects of Mild Hypothyroidism

Launched by OREGON HEALTH AND SCIENCE UNIVERSITY · Nov 28, 2007

Keywords

ClinConnect Summary

Thyroid hormone is essential for neurocognitive and metabolic function, and patients with overt thyroid dysfunction have well-described alterations in mood, cognition, energy expenditure, and body composition. However, it is not clear that patients with more mild degrees of thyroid dysfunction have clinically significant alterations in these parameters.

In addition, recent data suggest that variations in thyroid function within the laboratory reference range may also affect these parameters.

Patients with hypothyroidism are routinely treated with levothyroxine (L-T4) as replacement therap...

Gender

ALL

Eligibility criteria

• Inclusion Criteria:
• • Ages 20-75
• • Primary hypothyroidism on stable dose of L-T4 for \> 3 months
• • Documented elevated TSH off L-T4
• • Normal TSH level on usual dose of L-T4
• • No acute or chronic medical or psychiatric illnesses that affect thyroid function, mood or cognition
• • No medication use that affects thyroid function, mood or cognition (oral contraceptives or estrogen therapy allowed)
• • Normal score on screening Mini-Mental State Exam (MMSE) (to test for dementia)
• • Normal vision by screening examination
• • Normal hearing by screening examination
• • Non smoker
• Exclusion Criteria:
• • Failure to meet any of the above inclusion criteria
• • Inability to speak and comprehend English
• • A history of coronary artery disease
• • Screening hgb \<10
• • Screening wbc \> 10,000
• • Clinically significant abnormalities on screening metabolic set
• • Screening LDL cholesterol \> 160
• • Screening triglyceride \> 300
• • Significant abnormalities on screening ECG
• • Pregnancy or intent to become pregnant in next 6 months
• • Present or recent use of medications that affect thyroid hormone levels or interfere with thyroid hormone effects, including beta-blockers, lithium, glucocorticoids, or iodine containing agents
• • MMSE score \< 26