Dementia in developing countries: Does education play the same role in India as in the West?

Iyer, Gowri K.; Alladi, Suvarna; Bak, Thomas H.; Shailaja, Mekala; Mamidipudi, Annapurna; Rajan, Amulya; Gollahalli, Divyaraj; Chaudhuri, Jaydip Ray; Kaul, Subhash

doi:10.1590/S1980-57642014DN82000008

ABSTRACT

Evidence suggests that education protects from dementia by enhancing cognitive reserve. However, this may be influenced by several socio-demographic factors. Rising numbers of dementia in India, high levels of illiteracy and heterogeneity in socio-demographic factors provide an opportunity to explore this relationship.

Objective:

To study the association between education and age at dementia onset, in relation to socio-demographic factors.

Methods:

Association between age at dementia onset and literacy was studied in relationship to potential confounding factors such as gender, bilingualism, place of dwelling, occupation, vascular risk factors, stroke, family history of dementia and dementia subtypes.

Results:

Case records of 648 dementia patients diagnosed in a specialist clinic in a University hospital in Hyderabad, India were examined. All patients were prospectively enrolled as part of an ongoing longitudinal project that aims to evaluate dementia subjects with detailed clinical, etiological, imaging, and follow-up studies. Of the 648 patients, 98 (15.1%) were illiterate. More than half of illiterate skilled workers were engaged in crafts and skilled agriculture unlike literates who were in trade or clerical jobs. Mean age at onset in illiterates was 60.1 years and in literates 64.5 years (p=0.0002). Factors independently associated with age at dementia onset were bilingualism, rural dwelling and stroke, but not education.

Conclusion:

Our study demonstrates that in India, rural dwelling, bilingualism, stroke and occupation modify the relationship between education and dementia.

Key words
education; dementia; stroke; bilingualism; rural dwelling

RESUMO

Evidências sugerem que a educação protége de demência pelo fortalecimento da reserva cognitiva. Todavia, pode ser influenciado por vários fatores socioeconômicos. O aumento no número de demência na Índia, altos índices de analfabetismo e heterogeneidade de fatores sociodemográficos fornecem uma oportunidade para explorar estas relações.

Objetivo:

Estudar a associação entre educação e idade no início da demência em relação aos fatores sociodemográficos.

Métodos:

A associação entre idade de início da demência e alfabetismo foi estudado em relação aos potenciais fatores confundidores, como gênero, bilinguismo, local de moradia, ocupação, fatores de risco vasculares, acidente vascular cerebral (AVC), história familiar de demência e subtipos de demência.

Resultados:

Arquivos de 648 pacientes com demência, diagnosticados numa clínica especializada no Hospital Universitário em Hyderabad, foram avaliados. Todos os pacientes foram prospectivamente incluídos num projeto de acompanhamento longitudinal cujo objetivo é avaliar indivíduos com demência através de estudo de detalhado de acompanhamento clínico, etiológico e de imagem. Dos 648 pacientes, 98 (15%) eram analfabetos. Mais da metade dos analfabetos estavam envolvidos em trabalhos manuais ao contrário dos alfabetizados, envolvidos em comércio ou escritórios. A idade média de início em analfabetos foi de 60,1 anos e entre alfabetizados 64,5 anos de idade (p=0,0002). Os fatores independentemente associados à idade de início da demência foram bilinguismo, AVC, moradia rural, mas não educação.

Conclusão:

Nosso estudo demonstra que na Índia, moradia rural, bilinguismo, AVC e ocupação modificam a relação entre educação e demência.

Palavras-chave
educação; demência; acidente vascular cerebral; bilinguismo; moradia rural

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Publication Dates

Publication in this collection
Apr-Jun 2014

History

Received
02 Mar 2014
Accepted
20 May 2014

This is an open-access article distributed under the terms of the Creative Commons Attribution License

[1] ¹
Kalaria RN, Maestre GE, Arizaga R, et al. Alzheimer's disease and vascular dementia in developing countries: prevalence, management, and risk factors. Lancet Neurol 2008;7:812-826.

[2] ²
Richards M, Deary IJ. A life course approach to cognitive reserve: a model for cognitive aging and development? Ann Neurol 2005;58:617-622.

[3] ³
Stern Y. What is cognitive reserve? Theory and research application of the reserve concept. J Int Neuropsychol Soc 2002;8:448-460.

[4] ⁴
Katzman R. Education and the prevalence of dementia and Alzheimer's disease. Neurology 1993;43:13-20.

[5] ⁵
Mortimer JA, Snowden DA, Markesbery WR. Head circumference, education and risk of dementia: findings from the Nun Study. J Clin Exp Neuropsychol 2003;25:671-679.

[6] ⁶
Karp A, Kareholt I, Qic C, Bellander T, Winblad B, Fratiglioni L. Relation of education and occupation-based socioeconomic status to incident Alzheimer's disease. Am J Epidemiol 2004;15:175-183.

[7] ⁷
Bonaiuto S, Rocca WA, Lippi A, et al. Impact of education and occupation on prevalence of Alzheimer's disease (AD) and multi-infarct dementia (MID) in Appignano, Macerata Province, Italy. Neurology 1990; 40:346.

[8] ⁸
Zhang MY, Katzman R, Salmon D, et al. The prevalence of dementia and Alzheimer's disease in Shanghai, China: impact of age, gender, and education. Ann Neurol 1990;27:428-437.

[9] ⁹
Fratiglioni L, Grut M, Forsell Y, et al. Prevalence of Alzheimer's disease and other dementias in a elderly urban population:relationship with age, sex, and education. Neurology 1991;41:1886-1892.

[10] ¹⁰
Brucki SMD. Illiteracy and dementia. Dement Neuropsychol 2010;4:1 53-157.

[11] ¹¹
Prince M, Acosta D, Ferri CP. Dementia incidence and mortality in middle-income countries, and associations with indicators of cognitive reserve: a 10/66 Dementia Research Group population-based cohort study. Lancet 2012;380:50-58.

[12] ¹²
Bennett DA, Wilson RS, Schneider JA, et al. Education modifies the relation of AD pathology to level of cognitive function in older persons. Neurology 2003;24:1909-1915.

[13] ¹³
Chandra V, Pandav R, Dodge HH, et al. Incidence of Alzheimer's disease in a rural community in India. The Indo-US study. Neurology 2001; 57:985-989.

[14] ¹⁴
Poddar K, Kant S, Singh A, Singh TB. An epidemiological study of dementia among the habitants of eastern Uttar Pradesh, India. Ann Indian Acad Neurol 2011;14:164-168.

[15] ¹⁵
Sharp ES, Gatz M. The relationship between Education and Dementia An Updated Systematic Review. Alzheimer Dis Assoc Disord 2011; 25:289-304.

[16] ¹⁶
Elias MF, Beiser A, Wolf PA, Au R, White RF, D'Agostino RB. The preclinical phase of Alzheimer disease: A 22-year prospective study of the Framingham Cohort. Arch Neurol 2000;57:808-813.

[17] ¹⁷
Linn RT, Wolf PA, Bachman DL, et al. The 'preclinical phase' of probable Alzheimer's disease. A 13-year prospective study of the Framingham cohort. Arch Neurol 1995;52:485-490.

[18] ¹⁸
Hall KS, Gao S, Unverzagt FW, Hendrie HC. Low education and childhood rural residence Risk for Alzheimer's disease in African Americans. Neurology 2000;11:95-99.

[19] ¹⁹
Letenneur L, Gilleron V, Commenges D, Helmer C, Orgogozo JM, Dartigues JF. Are sex and educational level independent predictors of dementia and Alzheimer's disease? Incidence data from the PAQUID project. J Neurol Neurosurg Psychiatry 1999;66:177-183.

[20] ²⁰
Ott A, Breteler MMB, Harskamp FV, et al. Prevalence of Alzheimer's disease and vascular dementia: association with education. The Rotterdam study. BMJ 1995;310:970-973

[21] ²¹
Bialystok E, Craik FI, Freedman M. Bilingualism as a protection against the onset of symptoms of dementia. Neuropsychologia 2007;45:459-464.

[22] ²²
Chertkow H, Whitehead V, Phillips N, Wolfson C, Atherton J, Bergman H. Multilingualism (but not always bilingualism) delays the onset of Alzheimer disease: evidence from a bilingual community. Alzheimer Dis Assoc Disord 2010;24:118-125.

[23] ²³
Craik FI, Bialystok E, Freedman M. Delaying the onset of Alzheimer disease: bilingualism as a form of cognitive reserve. Neurology 2010;75:1726-1729.

[24] ²⁴
Schweizer TA, Ware J, Fischer CE, Craik FI, Bialystok E. Bilingualism as a contributor to cognitive reserve: evidence from brain atrophy in Alzheimer's disease. Cortex 2012;48:991-996.

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Richards M, Deary IJ. A life course approach to cognitive reserve: a model for cognitive aging and development? Ann Neurol 2005;58:617-622.

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Freedman M, Alladi S, Chertkow H, et al. "Delaying Onset of Dementia: Are Two Languages Enough?," Behavioural Neurology, vol. 2014, Article ID 808137, 8 pages, 2014.

[27] ²⁷
Costa A, Hernández M, Costa-Faidella J, Sebastián-Gallés N. On the bilingual advantage in conflict processing:now you see it, now you don't. Cognition 2009;113:135-149.

[28] ²⁸
Bialystok E, Craik FI, Luk G. Bilingualism: consequences for mind and brain. Trends Cogn Sci 2012;16:240-250.

[29] ²⁹
Garbin G, Sanjuan A, Forn C, et al. Bridging language and attention: brain basis of the impact of bilingualism on cognitive control. Neuroimage 2010;53:1272-1278.

[30] ³⁰
Kavé G, Eyal N, Shorek A, Cohen-Mansfield J. Multilingualism and cognitive state in the oldest old. Psychol Aging 2008;23:70-78.

[31] ³¹
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Hodges JR, Berrios G, Breen K. The multidisciplinary memory clinic approach. In: Berrios G, Hodges JR (eds). Memory disorders in psychiatric practice. Cambridge: Cambridge University Press; 2000:101-121.

[33] ³³
Mioshi E, Dawson K, Mitchell J, Arnold R, Hodges JR. The Addenbrooke's Cognitive Examination Revised (ACE-R): a brief cognitive test battery for dementia screening. Int J Geriatr psychiatry 2006;21:1078-1085.

[34] ³⁴
Borsboom D. Measuring the Mind: Conceptual Issues in Contemporary Psychometrics. Cambridge University Press. Cambridge; 2000.

[35] ³⁵
Ganguli M, Ratcliff G, Chandra V, et al. A Hindi version of the MMSE: the development of a cognitive screening instrument for a largely illiterate rural elderly population in India. Int J Geriatr Psychiatry 1995;10:367-77.

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Alladi S, Mekala S, Chadalawada SK, Jala S, Mridula R, Kaul S. Subtypes of Dementia: A Study from a Memory Clinic in India. Dement Geriatr Cogn Disord 2011;10:32-38.

[37] ³⁷
Shailaja M, Suvarna A, Rukmini MK. Dementia diagnosis in illiterates: Adaptation and usefulness of a global cognitive screening test-Addenbrooke's Cognitive Examination Revised (ACE-R). Ann Indian Acad Neurol 2008;11:S175-S175.

[38] ³⁸
Morris JC. The Clinical Dementia Rating (CDR): current version and scoring rules. Neurology 1993;43:2412-2414.

[39] ³⁹
McKhann G, Drachman D, Folstein M, Katzman R, Price D, Stadlan EM. Clinical diagnosis of Alzheimer's disease: report of theNINCDS-ADRDA Work Group under the auspices of Department of Health and Human Services Task Force on Alzheimer's Disease. Neurology 1984;34:939-944.

[40] ⁴⁰
Roman GC, Tatemichi TK, Erkinjuntti T, et al: Vascular dementia: diagnostic criteria for research studies - report of the NINDSAIREN International Workshop. Neurology 1993;43:250-260.

[41] ⁴¹
Neary D, Snowden JS, Gustafson L, et al. Frontotemporallobar degeneration: a consensus on clinical diagnostic criteria. Neurology 1998;51: 1546-1554.

[42] ⁴²
McKeith IG, Dickson DW, Lowe J, et al. Consortium on DLB: Diagnosis and management of dementia with Lewy bodies: third report of the DLB consortium. Neurology 2005;65:1863-1872.

[43] ⁴³
Census of India 2001 India. State of Literacy (Chapter 7), Provisional Population Totals, Series 1, India, Paper 1 of 2001.

[44] ⁴⁴
Mohanty AK. Bilingualism in multilingual society: Psychosocial and pedagogical implications. Mysore,India: Central Institute of Indian Languages; 1994.

[45] ⁴⁵
National Classification of Occupations (NCO). CSO, Director General of employment and training, Ministry of labour, Government of India, CS-1. 2004.

[46] ⁴⁶
Shelley BP, Al Khabouri J. The spectrum of dementia: frequency, causes and clinical profile - a national referral hospital-based study in Oman. Dement Geriatr Cogn Disord 2007;24:280-287.

[47] ⁴⁷
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