Affiliation:
1. Medical School University of Western Australia Perth WA Australia
2. Clinical Biochemistry Department, PathWest Laboratory Medicine Fiona Stanley Hospital Perth WA Australia
3. WA Centre for Health & Ageing University of Western Australia Perth WA Australia
4. Queensland Research Centre for Peripheral Vascular Disease James Cook University Townsville QLD Australia
5. Department of Vascular and Endovascular Surgery Townsville Hospital Townsville QLD Australia
6. Perron Institute for Neurological and Translational Science Perth WA Australia
7. Department of Endocrinology and Diabetes Fiona Stanley Hospital Perth WA Australia
Abstract
AbstractObjectivePrevalence of subclinical thyroid disease increases with age, but optimal detection and surveillance strategies remain unclear particularly for older men. We aimed to assess thyroid stimulating hormone (TSH) and free thyroxine (FT4) concentrations and their longitudinal changes, to determine the prevalence and incidence of subclinical thyroid dysfunction in older men.Design, Participants and MeasurementsLongitudinal study of 994 community‐dwelling men aged ≥70 years without known or current thyroid disease, with TSH and FT4 concentrations assessed at baseline and follow‐up (after 8.7 ± 0.9 years). Factors associated with incident subclinical thyroid dysfunction were examined by logistic regression and receiver operating characteristic analyses.ResultsAt baseline, 85 men (8.6%) had subclinical hypothyroidism and 10 (1.0%) subclinical hyperthyroidism. Among 899 men euthyroid at baseline (mean age 75.0 ± 3.0 years), 713 (79.3%) remained euthyroid, 180 (20.0%) developed subclinical/overt hypothyroidism, and 6 (0.7%) subclinical/overt hyperthyroidism. Change in TSH correlated with baseline TSH (r = .16, p < .05). Change in FT4 correlated inversely with baseline FT4 (r = −0.35, p < .05). Only higher age and baseline TSH predicted progression from euthyroid to subclinical/overt hypothyroidism (fully‐adjusted odds ratio [OR] per year=1.09, 95% confidence interval [CI] = 1.02‐1.17, p = .006; per 2.7‐fold increase in TSH OR = 65.4, CI = 31.9‐134, p < .001). Baseline TSH concentration ≥2.34 mIU/L had 76% sensitivity and 77% specificity for predicting development of subclinical/overt hypothyroidism.ConclusionsIn older men TSH concentration increased over time, while FT4 concentration showed little change. Subclinical or overt hypothyroidism evolved in one fifth of initially euthyroid men, age and higher baseline TSH predicted this outcome. Increased surveillance for thyroid dysfunction may be justified in older men, especially those with high‐normal TSH.
Funder
Sylvia and Charles Viertel Charitable Foundation
National Health and Medical Research Council
Subject
Endocrinology, Diabetes and Metabolism,Endocrinology