Thyroid dysfunction, cognition and mood in the elderly

Abstract

Aim: To determine the prevalence of thyroid dysfunction in the elderly and to analyze the association between thyroid function, cognition and mood. Type of study: Observational, cross-sectional and analytical study. Location: Ponte Family Health Unit. Population: Random sample of individuals aged 65 and above. Methods: A questionnaire on socio-demographic and clinical characteristics was administered. Cognitive function was assessed using the Mini-Mental State Examination (MMSE) and mood was assessed by the Hospital Anxiety and Depression Scale. Fasting blood samples were collected to measure TSH (Thyroid-stimulating Hormone) and free thyroxine levels. Odds ratios (OR) and 95% confidence interval (95% CI) were estimated using unconditional logistic regression to test the association between cognitive dysfunction and mood disorders,. Adjusted means in the domains assessed by the MMSE were calculated using multiple linear regression. Results:We evaluated 263 individuals (52.5% female), with a mean age of 72.1 years (± 5.3). In the total sample, 21.7% had a score suggesting dementia, 12% had scores suggesting anxiety and 16.8% had scores suggesting depression. Four individuals had hypothyroidism (1.5%), 14 had subclinical hypothyroidism (5.3%), 3 had hyperthyroidism (1.1%) and 2 had subclinical hyperthyroidism (0.8%). Higher TSH levels were significantly associated with anxiety (OR = 1.25; 95% CI 1.01-1.67). No significant differences were found between TSH levels and cognitive dysfunction and depression. The prevalence of dementia was significantly higher in patients with mood disorders. Conclusions: The prevalence of thyroid dysfunction found in our study was comparable to published rates. There was an association found between TSH levels and anxiety. No association was found between thyroid hormone levels and the presence of cognitive impairment or depressive symptoms.