CLINICAL THYROIDOLOGY FOR THE PUBLIC
A publication of the American Thyroid Association
SUBCLINICAL THYROID DISEASE
Subclinical thyroid disease is not associated with altered sleep quality in older men
ABBREVIATIONS & DEFINITIONS
Overt Hypothyroidism: clear hypothyroidism an increased TSH and a decreased T4 level. All patients with overt hypothyroidism are usually treated with thyroid hormone pills.
Overt Hyperthyroidism: a condition where the thyroid gland is overactive and produces too much thyroid hormone. Hyperthyroidism may be treated with antithyroid meds (Methimazole, Propylthiouracil), radioactive iodine or surgery.
Subclinical Hypothyroidism: a mild form of hypothyroidism where the only abnormal hormone level is an increased TSH. There is controversy as to whether this should be treated or not.
Subclinical Hyperthyroidism: a mild form of hyperthyroidism where the only abnormal hormone level is a decreased TSH.
TSH: thyroid stimulating hormone – produced by the pituitary gland that regulates thyroid function; also the best screening test to determine if the thyroid is functioning normally.
Thyroxine (T4): the major hormone produced by the thyroid gland. T4 gets converted to the active hormone T3 in various tissues in the body.
Euthyroid: a condition where the thyroid gland as working normally and producing normal levels of thyroid hormone.
Overt thyroid disease indicates that both the TSH is and the T4 levels are abnormal. Subclinical thyroid disease indicates that only the TSH is abnormal – T4 and T3 levels are normal. While overt thyroid disease has clear cut adverse effects on health and requires treatment, the effect of subclinical thyroid disease on health is much less clear. Multiple studies have been done to try to determine if subclinical thyroid disease has a significant negative impact on health and quality of life. Sleep disturbances are common, especially in the elderly. The present study was done to see if subclinical thyroid disease impacts sleep quality in older men.
THE FULL ARTICLE TITLE:
Akatsu H et al. Association between thyroid function and objective and subjective sleep quality in older men: the Osteoporotic Fractures in Men (MrOs) study. Endocr Pract. January 21, 2014:1-34 [Epub ahead of print].
SUMMARY OF THE STUDY
A total of 682 men 65 years and older were included in this study. Each participant had thyroid function studies and an assessment of sleep quality. Anyone taking thyroid hormone replacement or with abnormal levels of free T4 was excluded from the study. For study purposes, subclinical hyperthyroidism was defined as a serum TSH less than 0.55 mIU/L and subclinical hypothyroidism as a serum TSH greater than 4.78 mIU/L. A total of 38 subjects (6%) had subclinical hypothyroidism and 15 (2%) had subclinical hyperthyroidism. Individuals with subclinical hypothyroidism had a slightly shorter, mean duration of waking after initially getting to sleep. There were no other differences in sleep quality. Subjects with subclinical hyperthyroidism reported sleeping 44 fewer minutes per night than euthyroid men. It was concluded that subclinical thyroid disease was not associated with any significant alterations in sleep quality in older men.
WHAT ARE THE IMPLICATIONS OF THIS STUDY?
The present study provides data that sleep quality is not significantly worsened in those with mild thyroid dysfunction in older men. This is important due to the high frequency of sleep disorders in the elderly. Thus, abnormal sleep is not a reason to consider treating subclinical thyroid disease.
—Frank Crantz, MD
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