Risk of progression to overt thyroid dysfunction in elderly persons with subclinical hypothyroidism

January 01, 0001

Risk of progression to overt thyroid dysfunction in elderly persons with subclinical hypothyroidism

In this study (the Blue Mountains Eye Study) Australian researchers aimed to assess the 5-year incidence, progression and risk factors for development of thyroid dysfunction in an older Australian population. It was a longitudinal population-based cohort study that recruited 1768 participants (at least 55 years) in 1997-9. They had thyroid function assessed. After excluding participants reporting any form of treatment for their thyroid condition at baseline, 951 participants (91.4%) without thyroid dysfunction and 54 (5.4%) with thyroid dysfunction were re-examined 5-years later. Thyroid dysfunction was defined using serum thyrotropin (TSH) screen, followed by serum free T4 (FT4) assessment.

They found that the overall 5-year incidence of thyroid dysfunction was 4.7%. Obesity (body mass index 30 kg/m2 or more) and serum TSH over 2 mIU per L at baseline predicted incident overt hypothyroidism (OR 4.05) and (OR 5.46), respectively. The 5-year incidence of subclinical hypothyroidism was significantly higher in women than men, 2.5% vs 0.7%. Progression to overt hypothyroidism was observed in 17.9% of subjects with subclinical hypothyroidism over 5 years.

The authors concluded: “The 5-year incidence of thyroid dysfunction in this older population was relatively low, and was associated with obesity and serum TSH level over 2 mIU per L at baseline. Over one in six persons with subclinical hypothyroidism progressed to overt thyroid dysfunction over the 5-year period. Our findings highlight the need for appropriate management of subclinical hypothyroidism among older people.”

Worth finding and following.

For the full abstract, click here.

Internal Medicine Journalpublished online 4 Jan 2010. © 2007 by The Authors Journal compilation.
Five-year Incidence and Progression of Thyroid Dysfunction in an Older Population. Bamini Gopinath, Jie Jin Wang, Annette Kifley, Jack R Wall, Creswell J Eastman, Stephen R Leeder and Paul Mitchell. Correspondence to Bamini Gopinath: bamini_gopinath@wmi.usyd.edu.au

Category: T. Endocrine/Metbolic/Nutritional. Keywords: thyroid dysfunction, prevalence, incidence, progression, TSH, Blue Mountains Eye Study, obesity, thyroxine, longitudinal population-based cohort study
Synopsis edited by Dr Stephen Wilkinson, Melbourne, Australia. Posted on Global Family Doctor 20 January 2010

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