Hypothyreosis as the risk-factor of dementia in elderly

As known the thyroid status is essential for normal development and retention of cognitive function throughout life. The association between thyroid hormones and cognition has been recognized. Purpose: To identify the relation of thyreopathy with mild cognitive impairment (MCI) and probable Alzheimer's disease (AD) in aged patients from endemic region of Georgia. Non-vascular 110 MCI patients and 70 probable AD aged 60 to 70 years were investigated. Thyroid gland was evaluated by ultrasound. Thyroid gland hormones (FT-4, TSH) determined biochemically. Cognitive status evaluated by Mini Mental Examination Scale (MMSE). AD diagnosis was made according to NINDS- ADRDA criteria. Brain was visualized by conventional MRI. Depressive disorder was evaluated by Hamilton Depression Rating Scale (HAM-D). Control comprised 30 aged matched healthy persons. Spearman rank correlation and the ?2-test was used to assess associations among categorical variables. Untreated hypothyreosis was detected in 37 (33.6%) patients with MCI and 11 (15.8%) patients with probable AD. Hyperthyreosis revealed in 6 (5.45%) patients with MCI. Euthyreoid state detected in 4 (3.6%) patients with MCI and 7 (10%) patients with probable AD. Severe depression (HAM-D > 12) was detected in 2 (2.8%) patients with euthyreoid state and probable AD. Positive correlation was found between hypothyreosis and cognitive status decline in aged patients with MCI and probable AD (r = 0.34; P < 0.05). Untreated hypothyreosis can be considered as the risk factor for cognitive decline in aged patients with non-vascular MCI and probable AD.