06.02.01. What is the estimated prevalence and incidence of dementia and the source of these estimates? | India

06.02.01. What is the estimated prevalence and incidence of dementia and the source of these estimates? | India

08 Jul 2022

Prevalence of dementia has been reported based on several population based epidemiological studies conducted across India over the last two decades. According to the Dementia India Report 2010 (Alzheimer’s and Related Disorders of India [ARDSI], 2010) projections, an estimated 5.29 million Indian people aged over 60 have dementia. The more recent Global Burden of Disease study estimated that 3.69 million people had Alzheimer’s disease or other dementias in India in 2019 (India State-Level Disease Burden Initiative Neurological Disorders Collaborators, 2021). There is variability in reported prevalence rates ranging from 0.3% (Rodriguez et al., 2008) to 14.9% (Seby et al., 2011) among older adults, depending on the sample size, age of the cohort, geographical area considered (rural vs. urban population) and the year of the study (Table 6.1). Meta-analysis of individual studies have reported pooled prevalence estimates for dementia to range from 3.4% (95% CI = 2.0 to 5.0) to 4.4% (2.2-7.2) in India (Dhiman et al., 2021; Farina et al, 2020).

Differences in estimates may be related to the adoption of different methods and defining criteria, but differences in environmental and genetic risk factors may also contribute. Recognising the need to study dementia prevalence using a uniform method, the Government of India’s scientific research funding agency, specifically the Department of Biotechnology, has initiated a multi-centric study across rural, urban, and tribal areas to observe dementia prevalence (Bhatt, 2020).

Table 6.1 shows dementia prevalence across the country

S.No Publication Location Age of population surveyed Number

screened

Screening tool Confirmation tool Prevalence of dementia
1 Razdan et al., (1994)

Neuroepidemiology

Rural Kashmir All 63,645   Neurological examination No dementia was found
2 Shaji et al., (1996)

The British Journal of Psychiatry

Rural Kerala ≥60 years 2067 Vernacular adaptation of the Mini Mental State Examination.

 

Score of 23 and below -a detailed neuropsychological evaluation by CAMDEX-Section B.

DSM-III-R criteria for dementia

 

Subcategorisation of dementia was done based on ICD-10 diagnostic criteria

 33.9 per 1000

 

 

3 Rajkumar, Kumar and Thara (1997)

International Journal of Geriatric Psychiatry

Rural

Tamil Nadu

≥60 years 750 Geriatric Mental State schedule (GMS).   3.5%
4 Chandra et al., (1998)

Neurology

Rural

Haryana

≥55 years 5126 Hindi cognitive and functional screening instruments, developed for and validated in this population. DSM- IV

diagnostic criteria,

Clinical Dementia Rating Scale (CDR),

National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer’s Disease and Related Disorders Association (NINCDS-ADRDA) criteria.

≥55 years: 0.84%

≥65 years: 1.36%

5 Vas et al., (2001)

International Psychogeriatrics

Urban

Maharashtra

≥40 years 24,488 Self-report or interviewer-rated protocols based on the Sandoz Clinical Assessment Geriatric Scale.

 

“A score +2 SD above the mean were screened for cognitive functioning using a modified and translated version of the Mini Mental State Examination”

Detailed neurological, psychiatric, and neuropsychological evaluation as well as  laboratory investigations and other tests etc.

 

DSM-IV diagnostic criteria.

≥40 years: 0.43%

 

≥65 years: 2.44%

6 Shaji, Bose and Verghese (2005)

The British Journal of Psychiatry

 

Urban

Kerala

≥65 years 1934 Vernacular adaptation of the Mini-Mental State Examination Diagnoses according to DSM-IV criteria. Identified cases were categorised by ICD-10 criteria. 33.6 per 1000
7 Das et al., (2006)

The Indian Journal of Medical Research

Urban

West Bengal

≥50 years 52,377 National Institute of Mental Health and Neurosciences (NIMHANS) used questionnaire.

 

A modified version of

“Cognitive Battery”

used by Ganguli et al.

DSM-IV

criteria

87.82 per 100,000 population
8 Rodriguez et al.,

(2008)

Lancet

Urban/Rural

Tamil Nadu

≥65 years Urban: 1005

 

Rural: 999

10/66 dementia diagnostic algorithm and by computerised application of dementia criterion from the DSM-IV.   10/66 standardized prevalence:

 

Urban: 8.2%

 

Rural: 8.7%

 

DSM-IV dementia standardized prevalence:

 

Urban: 0.9%

 

Rural: 0.3%

9 Das et al., (2008)

The Journal of the Association of Physicians of India

Urban

West Bengal

≥60 years 5430 National Institute of Mental Health and Neurosciences (NIMHANS) developed questionnaire.

 

A modified version of

“Cognitive Battery”

developed by Ganguli et al.

DSM-IV

criteria and for “individual subtypes the standard

Definitions of NINDS-ADRDA” were used.

 

≥60 years: 7.89 per 1000 elderly

 

 

10 Banerjee et al., (2008)

Neuroepidemiology

Urban

West Bengal

≥50 years 6129 Screening questionnaire

 

Kolkata Cognitive Test Battery

DSM-IV criteria ≥50 years: 0.62%

≥60 years: 1.25%

11 Raina et al., (2008)

Annals of Indian Academy of Neurology

Migrant community cluster of Jammu city Kashmir

 

≥60 years 200 Kashmiri version of the Mini-Mental State Examination

 

A functional ability questionnaire- Everyday Abilities Scale for India (EASI)

Clinical evaluation was carried out by a neurologist.

 

Patients diagnosed with dementia  further underwent detailed laboratory investigations and MRI scan.

6.5%
12 Mathuranath et al., (2010)

International Journal of Geriatric Psychiatry

Urban

Kerala

≥55 2466 Addenbrooke’s cognition examination (ACE) (Mathuranath et al., 2000), a cognition screening battery like the CERAD screening battery.

 

An instrumental activities of daily living scale for the elderly (IADL-E)

A semi-structured family interview with family members.

 

The evaluations included:

 

a) Cognition and behavioural symptoms (over past month).

 

b) Clinical evaluation.

 

c) Neuropsychological evaluation.

 

d) Further evaluation – screening blood investigations and/or neuroimaging tests.

 

DSM-IV criteria used to diagnose dementia.

 

≥65 years: 4.86%

 

13 Saldanha et al., (2010)

Indian Journal of Psychiatry

Urban

Maharastra

≥65 2119 Mini Mental State Examination (MMSE

 

‘Cognitive test component’ of the 10/66 research groups instrument – community screening instrument for Dementia (CSI-D),

ICD-10 Diagnostic Research Criteria. ≥65 years: 4.1%
14 Seby, et al., (2011)

Indian Journal of Psychiatry

Urban Pune – Maharashtra >65 202 Hindi version Mini-Mental State Examination (MMSE)   14.9%
15 Poddar et al., (2011)

Annals of Indian Academy of Neurology

Urban and Rural

Uttar Pradesh

≥50 years 2890 Hindi version of the Mini Mental State Examination (MMSE)   5.1%
16 Raina et al., (2014)

North American Journal of Medical Sciences

Urban, Rural, Tribal Himalaya ≥60 years 2000 Hindi Mental State Examination (HMSE) Detailed clinical history.

 

Subjects examined for

cognitive or intellectual, functional, and  psychiatric or behavioural symptoms.

1.6%

 

17 Raina, Chander and Bhardwaj (2016)

Journal of Neurosciences in rural practice

Tribal Himachal Pradesh ≥60 years 481 Bharmouri Mental State Examination [BMSE] The clinical evaluation was carried out by a neurologist. No dementia
18 Banerjee et al., (2017)

International Journal of Geriatric Psychiatry

Urban Bengal ≥60 years 100,802 Two dementia pertinent questions to family members

 

Detailed clinical history

 

Kolkata Cognitive Screening Battery

DSM-IV criteria for dementia

 

 

1.53%

Table Source: (Razdan et al., 1994;  Shaji et al., 1996; Rajkumar, Kumar and Thara, 1997; Chandra et al., 1998; Vas et al., 2001; Shaji, Bose and Verghese, 2005; Rodriguez et al., 2008; Das et al., 2006; Das et al., 2007; Das et al., 2008; Raina et al., 2008; Mathuranath et al., 2010 ; Saldanha et al., 2010; Seby, Chaudhary and Chakraborty, 2011, Poddar et al., 2011; Raina et al., 2014; Raina, Chander and Bhardwaj, 2016; Banerjee et al., 2017).

Moreover, there are few studies reporting incidence of dementia in India and results are varied (Table 6.2).

Table 6.2 shows studies reporting incidence rates for dementia in India

S.No. Publication Method Screening tool Confirmation tool Incidence
1. Chandra et al., 2001, Neurology 28 villages in Haryana (North India)

2 years.

Hindi cognitive screening battery based on the Consortium

to Establish a Registry for AD (CERAD) neuropsychological

panel.

DSM-IV criteria and

the Clinical Dementia Rating scale CDR

Incidence rates per 1000 persons-years for AD: 3.24 (95% CI: 1.48-6.14) for those aged ≥ 65 years.

1.74 (95% CI: 0.84-3.20) for those aged ≥55 years.

Standardised against the age distribution of the 1990 US Census, the overall incidence rate in those aged 65 years was 4.7 per 1000 person-years.

2. Mathuranath et al., 2012, Neurology India 4 urban and semi-urban regions of Trivandrum city in Kerala. Malayalam Addenbrooke’s cognitive examination (mACE). Clinical evaluation by neurologist based on the DSM-IV criteria. Incidence rates per 1000 person-years for AD:

11.67 (95% CI: 10.9-12.4) for those aged ≥55 years.

15.54 (95% CI: 14.6-16.5) for those aged ≥65 years.

Standardised against the year 2000 U.S. Census, the age-adjusted incidence rate was 9.19 (95% CI: 9.03-9.35) per 1000 person-years.

3. Banerjee et al., 2017, Int Journal of GerPsychiatry Kolkata, West Bengal Two dementia pertinent questions to family members.

 

Detailed clinical history

 

Kolkata Cognitive Screening Battery

DSM-IV criteria Average annual incidence rate of dementia was 72.57 per 100,000 ≥ 55 years age.

 

Source: (Chandra et al., 2001; Mathuranath et al., 2012; Banerjee et al., 2017)

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