Diagnostic Significance of Subclinical Hypothyroidism in Health Check-ups

Abstract

Subclinical hypothyroidism (SHT) is defined as an asymptomatic state associated with normal serum FT4 and a slightly elevated serum TSH concentration. Patients with SHT have a high rate of progression to clinically overt hypothyroidism (OHT), and in addition, SHT is thought to be a risk factor for atherosclerosis and coronary heart disease. The aim of this study was to identify SHT patients and refer them to a thyroid specialist for treatment and management. We retrospectively studied 1168 subjects (324 males and 844 females) who received health check-ups including thyroid function tests in our Health Service Association Clinic over a period of three years and eleven months. Sixty subjects (5.1%) were diagnosed as SHT. The TSH/FT4 ratio (SHT index) was found to be helpful for diagnosing SHT. The main causes of SHT were Hashimoto's thyroiditis, excess dietary iodine intake. L-thyroxine replacement therapy was recommended for patients with a TSH greater than 10 μU/mL. For patients with very mild SHT who are pregnant or anticipate becoming pregnant, L-thyroxine therapy should be started. We devised a flowchart for the diagnosis and management of SHT.

The threshold of hypothyroidism after radiation therapy for head and neck cancer: a retrospective analysis of 116 cases

“…In the normal population, the prevalence of subclinical hypothyroidism was reported to range from 1–10% [ 20 , 21 ], and 10.6% of males and 12.3% of females met the criteria for subclinical hypothyroidism in elderly people aged 70 to 79 years [ 22 ]. In Japan, the prevalence of subclinical hypothyroidism in general health check-ups was 5.1% from April 2007 to February 2011 [ 23 ]. In the present study, the prevalence of subclinical hypothyroidism was 12.9% prior to treatment.…”