Prevalence of dementia in an urban population in Kerala, India

BACKGROUND: Dementia is emerging as an important health problem of elderly people in India. AIMS: To investigate the prevalence, psychosocial correlates and risk factors of various dementing disorders in an urban population in Kerala, southern India. METHOD: A door-to-door survey was conducted in the city of Kochi (Cochin) to identify residents aged > or =65 years using cluster sampling. Of 1934 people screened with a vernacular adaptation of the Mini-Mental State Examination, all those scoring at or below the cut-off of 23 were evaluated further and those with confirmed cognitive and functional impairment were assigned diagnoses according to DSM-IV criteria. Identified cases were categorised by ICD-10 criteria. Ten per cent of those screened as negative were evaluated at each stage. RESULTS: Prevalence of dementia was 33.6 per 1000 (95% CI 27.3-40.7). Alzheimer's disease was the most common type (54%) followed by vascular dementia (39%), and 7% of cases were due to causes such as infection, tumour and trauma. Family history of dementia was a risk factor for Alzheimer's disease and history of hypertension was a risk factor for vascular dementia. CONCLUSIONS: Dementia is an important health problem of the elderly population. Identification of risk factors points towards the possibility of prevention.