[Thyroid in the elderly (Part 1)]

Aging is associated with changes in thyroid function at several levels of regulation. Thyroid hormones levels are usually within the lower part of normal values reported in the general population. Two changes in aging are of clinical importance: a shift in the distribution of TSH levels, the 97.5th percentile of the TSH distribution being within 6 μUI/ml after 70 years and within 7.5 μUI/ml in subjects older than 80 instead of 4.5 μU/ml in the general population, and an increased prevalence of thyroid nodularity, requiring reliable and non-invasive methods of investigation in older people. Lastly, aging may be associated with comorbidities, high risk of drug interactions and under nutrition, which may make difficult the interpretation of laboratory data and in some cases induce iatrogenic thyroid diseases. Considering the high prevalence of the thyroid diseases in older patients and a better understanding of the physiopathological hormonal variations with the ageing, it seemed useful to propose a review to help the clinician in the care of these situations.