A clinico-epidemiological study of cognitive function status of community-dwelling elderly

Background: Cognitive decline and dementia are an important problem affecting quality-of-life in elderly and their caregivers. There is regional variation in prevalence of cognitive decline as well as risk factors from region to region. Aim: The aim was to determine the prevalence of dementia and cognitive decline and its various risk factors in the elderly population of more than 60 years in Eastern Uttar Pradesh (India). Materials and Methods: A camp-based study was conducted on rural population of Chiraigaon block of Varanasi district from February 2007 to May 2007. Block has 80 villages, of which 11 villages were randomly selected. Eleven camps were organized for elderly people in 11 randomly selected villages on predetermined dates. A total of 728 elderly persons of age > 60 years were examined, interviewed and data thus collected was analyzed. Elderly who got Hindi-mini-mental state examination (HMSE) score developed by Ganguli based on the Indo-US Cross-National Dementia Epidemiology Study) score <= 23 were evaluated further and in those with confirmed cognitive and functional impairment, diagnosis of dementia was assigned according to Diagnostic and Statistical Manual for Mental Disorder fourth edition criteria after ruling out any psychiatric illness or delirium. Based on International Classification of Diseases-10 diagnostic criteria sub-categorization of dementia was done. Results: Mean, median and 10th percentile of HMSE of the study population were 23.4, 24 and 17, respectively. About 14.6% elderly had scored <17. 42.9% of rural elderly population had HMSE score <23, 70.6% <27 and 27.7% between 23 and 27. Literate people had statistically significant higher mean HMSE score (26.1 +/- 3.9) than illiterate people (22.9 +/- 4.9). Other risk factors were female gender, malnutrition, and obesity. Prevalence of dementia was 2.74%; in male 2.70% and in female 2.80%. Most common type of dementia was Alzheimer (male 1.5%, female 1.5%) followed by vascular (male 1.2%, female 0.6%) and others 0.6% (male 0%, female 0.6%). Conclusions: Study showed that a very high percentage of rural elderly attending health camps had poor cognitive function score; though the prevalence of dementia was relatively low. Alzheimer dementia was most common, followed by vascular dementia, which was predominant in males. Illiteracy, age, and under-nutrition were the most important risk factors for poor cognitive function. Our study suggest that cut-off of HMSE score should be 17 (10th percentile) for illiterate population.