Cognitive function in subclinical hypothyroidism in elderly

AIM: To study the association of cognitive function with subclinical hypothyroidism in elderly. MATERIALS AND METHODS: It's a cross-sectional, case-control study of 103 patients (≥65 years) who met the criteria for subclinical hypothyroidism. Similarly 103 age, sex and education-matched healthy controls were taken. Serum TSH, free T3 and free T4 were measured. Cognitive functions were assessed by using Folstein Mini Mental Examination (MMSE) and clock drawing test. RESULTS: Out of the 103 diagnosed subclinical hypothyroidism cases, cognitive impairment (by MMSE) was found in 33 (30.9%) while it was present in only 15 (14.54%) out of 103 controls (P = 0.003), cognitive impairment (by CDT) was present in 32 patients (31.06%) out of 103 cases while it was present in 26 patients (25.24%) out of 103 controls (P > 0.05, insignificant). Mean TSH of subclinical hypothyroidism with cognitive impairment was 7.67 ± 1.22 mIU/liter and without cognitive impairment was 6.47 ± 0.98 mIU/liter (P value = 0.0001, significant). CONCLUSIONS: Prevalence of cognitive impairment was significantly higher in subclinical hypothyroidism as compared to controls. Presence of cognitive impairment correlated with the level of TSH; as TSH increased cognitive function declined.