PREVALENCE OF COGNITIVE DYSFUNCTION AND HYPOTHYROIDISM IN AN ELDERLY COMMUNITY POPULATION

Cognitive function was assessed in 801 elderly subjects (aged 65-92 ye ars) using the Mini Mental State Examination (MMSE). The mean (+/-SD) MMSE score in the age group 65-70 years was 27.8+/-5.6, and the score declined to 22.3+/-7.8 at the age 85-90 (P = 0.001). Abnormal MMSE sco res (less than 24) were found in 5.2% of the subjects aged 65-70 and g radually increased with age to 35.5% in the age group of 85-90. Serum thyroid-stimulating hormone (TSH) levels were determined in 751 subjec ts. Elevated TSH (>4.5 mIU/l) were detected in 112 people (14%). The p revalence of hypothyroidism was higher in females (18.2%) than in male s (9.7%). MMSE scores in 39 patients (14 males and 25 females) with un treated hypothyroidism were compared to the scores of 570 euthyroid el derly controls (235 males and 335 females). The mean +/-SD MMSE scores were 27.0+/-2.1 in hypothyroid males vs. 26.0+/-4.7 in male controls and 25.0+/-7.7 in hypothyroid females vs. 25.0+/-6.6 in female control s. The scores in the hypothyroid patients were not significantly diffe rent from the controls. Our data suggest that: a) the average cognitiv e performance declines with age; b) the percentage of subjects with ab normal MMSE scores increases with age, and is higher in females than i n males; c) the prevalence of hypothyroidism in the elderly population is 14% and is higher in females (18%) than in males (10%); and d) mil d untreated hypothyroidism is not associated with cognitive impairment .