Anosmia in Elderly: Predictor of Cognitive Impairment

The prevalence of olfactory impairment and cognitive impairment increases with age. Olfactory impairment has been associated with neurodegenerative diseases such as Alzheimer’s disease (AD) and Parkinson’s disease. The present study was carried out to find out the prevalence of anosmia in the elderly and cognitive impairment in the elderly along with the association of anosmia and cognitive impairment in the elderly. Present study is a hospital based, observational, case-control study, in which 100 elderly subjects (age >65 years, Males 64, Females 36, ratio 1.7:1), attending the geriatric OPD, were included as cases and 100 subjects (<65 years, Males54, females 46, ratio-1.1:1) as controls. Anosmia was assessed by Indian Smell Identification Test (INSIT), in which 10 essences were used and 1 point was awarded for correct and 0 for incorrect identification. A score of ≤ 4 indicates anosmia. All cases were subjected to thorough clinical examination and lab investigations. Cognitive impairment was diagnosed by 30 point mini-mental state examination (MMSE) where scores ≤ 23 indicates cognitive impairment. Statistical analysis was performed by using students ‘t’ test, chi square test p value and univariate analysis. Mean age in cases was 68.4±3.7 years and in controls is 39.4±7.9 years. Anosmia was detected in 64% of cases as compared to controls 4% (p <0.01). Mean INSIT score was significantly lower (4.02 + 1.88) in cases as compared to controis7.36 + 1.35, p< 0.01. Cognitive impairment was present in 50% of the cases and 1% control, (p<0.001). Mean MMSE score was also significantly lower in cases (20.99 + 5.1) than controls (27.47 + 1.79, p <0.001. Anosmia is found to be significantly associated with cognitive impairment in cases. Anosmia, a surrogate marker of cognitive impairment, is prevalent in elderly. Cognitive impairment is also prevalent in elderly. In elderly subjects, anosmia is associated with cognitive impairment. Keywords: Anosmia, Cognitive impairment, Geriatric age group