Thyroid Functions and Cognitive Decline in the Elderly.

Background The maintenance of cognitive health depends on thyroid hormones, and it is becoming more widely acknowledged that thyroid hormone issues may be a factor in cognitive decline in the aged. Objective This study aimed to investigate the association between thyroid hormone levels and cognitive decline among elderly individuals, considering the influence of age-related factors and comorbidities. Methodology Over the course of two years, 218 adults 60 years of age and older with clinically diagnosed hypothyroidism or subclinical thyroid disease were included in a prospective observational research. Serum levels of thyroid-stimulating hormone (TSH), free thyroxine (T4), and free triiodothyronine (T3) were measured at baseline and at 6, 12, 18, and 24-month intervals to evaluate thyroid function. The Mini-Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA) were used to assess cognitive function at the same intervals. Factors linked to cognitive deterioration were identified using multivariate regression analysis. Results The study found that TSH levels decreased from 3.20 ± 1.82 µIU/mL at baseline to 2.80 ± 1.51 by 24 months (p < 0.001), while free T4 levels increased from 13.50 ± 2.53 pmol/L to 14.20 ± 2.52 pmol/L (p = 0.020). Cognitive scores declined significantly, with MMSE scores dropping from 23.27 ± 4.64 to 21.80 ± 4.89 (p = 0.005) and MoCA scores from 21.20 ± 5.11 to 20.03 ± 5.51 (p = 0.012). Conclusion The results show a strong correlation between thyroid malfunction and cognitive loss in the elderly, emphasizing the need to closely monitor thyroid function to maintain cognitive function in this population.