Incidence of Alzheimer's disease in India: a 10 years follow-up study.

OBJECTIVE: To determine overall and age-specific incidence rates of Alzheimer's disease (AD) in a southern Indian province, Kerala. MATERIALS AND METHODS: A 10-year (2001-2011) prospective epidemiologic study of community residing subjects aged ≥55 years at enrollment. The catchment area included four urban and semi-urban regions of Trivandrum city in Kerala, India, was selected to provide a range of demographic and socioeconomic representation. Cognitive and functional ability screening were done at baseline and 24-month follow-up assessments. Consensus diagnostic procedures were done using the Diagnostic and Statistical Manual of Mental Disorders, 4 th edition (DSM-IV), and the National Institute of Neurological and Communicative Disorders and Stroke - Alzheimer's Disease and Related Disorders Association (NINDS-ADRDA) criteria for the diagnosis of dementia and AD. RESULTS: Among the 1066 eligible participants who were cognitively normal at baseline, 104 developed dementia (98 with AD) over a follow-up period of 8.1 years. The incidence rates per 1000 person-years for AD was 11.67 (95% CI: 10.9-12.4) for those aged ≥55 years and higher for those aged ≥65 years (15.54, 95% CI: 14.6-16.5). In those aged ≥65 years, the world age standardized incidence rate was 21.61 per 100,000, and standardized against the age distribution for the year 2000 U.S. Census, the age-adjusted incidence rate was 9.19 (95% CI: 9.03-9.35) per 1000 person-years. Incidence rate of AD increased significantly and proportionately with increasing age. CONCLUSION: These are the first AD incidence rates to be reported from southern India. The incidence rates appear to be much higher than that reported from rural north India, comparable with that reported from China, and marginally lower than that reported from the western world.

Dementia in Kerala, South India: prevalence and influence of age, education and gender.

BACKGROUND: Data on the prevalence of dementia in India with a large and aging population is scant. We studied prevalence of AD and dementia in Kerala, South India, and effects of age, education and gender on it. METHODS: 2-phase survey on 2466 individuals aged > or = 55 years living in community. Men constituted 41%, < 75 years age in 76.9% and education > or = 4 years in 69.6%. Screening (Phase I) using the instrumental activity of daily living scale for the elderly (IADL-E) and the Addenbrooke's cognition examination (ACE). Diagnostic-assessment (Phase II) was in 532 screen-positives and 247 (10%) screen-negatives. RESULTS: 93 (3.77%) > or = 55 years and 81 (4.86%) > or = 65 years of age had dementia. Age adjusted (against US-population in 2000) dementia (and AD) rates were 4.86% (1.91%) in age > or = 55 years and 6.44% (3.56%) in > or = 65 years. Odds for dementia (and AD) were high with increasing-age 5.89 (15.33) in 75-84, 13.23 (25.92) > or = 85 years, and in women 1.62 (2.95); and low 0.27 (0.16) if education was > or = 9 years. Age and low education increased dementia. Age and female gender increased AD. CONCLUSION: Prevalence of dementia and AD is higher than any reported from the subcontinent suggesting that dementia in Kerala in South India is not uncommon. Increasing age increased dementia and AD. Low-education is associated with dementia and female-gender with AD.

Qualitative aspects of learning, recall, and recognition in dementia.

OBJECTIVE: To determine whether learning and serial position effect (SPE) differs qualitatively and quantitatively among different types of dementia and between dementia patients and controls; we also wished to find out whether interference affects it. MATERIALS AND METHODS: We administered the Malayalam version of the Rey Auditory Verbal Learning Test (RAVLT) to 30 cognitively unimpaired controls and 80 dementia patients [30 with Alzheimer's disease (AD), 30 with vascular dementia (VaD), and 20 with frontotemporal dementia (FTD)] with mild severity on the Clinical Dementia Rating Scale. RESULTS: All groups were comparable on education and age, except the FTD group, who were younger. Qualitatively, the learning pattern and SPE (with primacy and recency being superior to intermediate) was retained in the AD, VaD, and control groups. On SPE in free recall, recency was superior to intermediate in the FTD group (P < 0.01 using Bonferroni correction). On recognition, the AD and VaD groups had more misses (P < 0.01), while the FTD group had more false positives (P < 0.01). CONCLUSION: Quantitative learning is affected by dementia. The pattern of qualitative learning remains unaltered in dementia in the early stages.