El impacto del modelo de cuadrícula en la fundación de ciudades

Alzheimer‟s Disease International, the umbrella organisation for national Alzheimer‟s associations, convened an international group of experts to generate up-to-date evidence-based estimates for the prevalence and numbers of people with dementia in all regions of the world (Ferri, Prince, Brayne, Brodaty, Fratiglioni, Ganguli, et al, 2005). Twelve international experts used the Delphi method to provide prevalence estimates for every World Health Organisation (WHO) world region and the results are considered the best estimates currently available. The Delphi method involves experts systematically reviewing the evidence base independently. The

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results are collated to compare estimates generated by each expert, and they then reach a consensus to provide the prevalence rates. The numbers affected will double every 20 years to 81.1 million by 2040 (Ferri et al, 2005). These estimates were derived with the assumption that there will be no changes in mortality rates, and no preventative or curative treatments will be developed. A point of interest is that most people with dementia were noted as living in developed countries (60% in 2001, rising to 71% by 2040). It is possible that this is an under-estimation of prevalence in developing regions. Possible explanations for this are scarce epidemiological surveys in these regions (Ferri et al, 2005).There are also differences in cultural beliefs, with some traditional approaches to health and well-being conflicting with western values (Butt & O‟Neil, 2004). The effects of ageing may also be experienced and treated differently in these cultures (Ramsey, Stevens, Bryan, Binder & Cockle-Hearne, 2009). For instance, some cultures remove responsibility from their elderly by taking over the older persons‟ responsibilities and treating them with respect. Thus the symptoms of dementia may be less obvious or tolerated as part of ageing (Rait, Burns, Baldwin, Morely, Chew-Graham & Leger, 2000; Purandare, Luthra, Swarbrick & Burns, 2007).

Finally, the lower life expectancy in some regions, such as Africa, could also account for lower rates of dementia, because people may not live into old age, therefore decreasing their potential to develop clinical conditions which have increased incidence in later life. Chen (2004) suggests that there may be methodological issues such as study design and differences in language, social customs and educational levels impacting on the validity of cognitive instruments which presume literacy, numeracy and knowledge of (and interest in) current events.

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Thus, confirmation and elaboration of discrepancies in prevalence in developing countries require more prospective studies, using appropriately harmonised diagnostic procedures (de Silva & Gunatilake, 2002). However, if this difference in disease frequency is genuine, it might suggest geographical variation in the distribution of critical risk and protective factors for and against dementia (Chen, 2004).

1.2.2 Prevalence rates in the UK

In 2006, the Alzhiemer‟s Society commissioned the London School of Economics and the Institute of Psychiatry at Kings College London to produce a report on dementia specifically in the UK (Albanese, Banerjee, Dhanasiri, Feernandez, Ferri, Knapp et al, 2007). Ten leading UK and European experts systematically reviewed the data. Using the Delphi method, they estimated that there are 683,597 people with dementia in the UK. This number is forecast to increase to 940,110 by 2021 and 1,735,087 by 2051, an increase of 35% over the next 15 years and 154% over the next 45 years. Early onset (onset before age of 65 years) dementia is comparatively rare, accounting for 2.2% (15,034) of all people with dementia in the UK. However, this could again be an under-estimation, since these people present much later into services.

The report estimates that 416,967 people with dementia (62%) have AD in the UK. The next most common forms are Vascular dementia (VaD) and mixed dementias, accounting for 27% of all cases. However, the „mixed dementia‟ classification is an anomaly, and it highlights the challenges of differential diagnosis in this area (Rockwood et al, 2007). In addition, Sellal et al (2004) state that current measures used to assess cognitive functioning place most emphasis on the domains that are typically impaired in patients with AD, therefore measures that fail to screen for executive functioning

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and language deficits are likely to result in an underestimation of the incidence of VaD.

1.2.3 Older adult ethnic minority groups in the UK

The report estimates that there are 11,392 people from Black and Minority Ethnic (BME) groups with dementia, accounting for 1.7% of all people with dementia. In contrast, studies suggest that BME groups have a greater incidence of dementia, the cause attributed to unidentified genes or other risk factors (Tang, Stern, Marder, Bell, Gurland, Lantigua et al, 1998). Indeed, the UK incidence estimates note that 6.1% of all people with dementia among BME groups are of younger onset compared with only 2.2% for the population as a whole, which possibly reflects the younger age profile of BME communities living within the UK. However, the „BME community‟ is a heterogeneous group composed of different religions, languages and cultures, therefore it is unlikely that genetic factors will account for early onset dementia in all of these ethnic groups. There is also evidence to suggest that measures used to assess cognitive decline, such as the MMSE, in older people from ethnic minority groups have high rates of false positives. There is also the possibility that dementia is under-diagnosed in minority ethnic groups due to their reluctance in accessing services (Eolas, 1999).

According to the 2001 census study there are an estimated 4.6 million (or 7.9 per cent) people in the UK belonging to non-White ethnic groups (ONS; Office of National Statistics, 2003). Indians were the largest of these groups (1.8 %), followed by Pakistanis‟ (1.3%), those of mixed ethnic backgrounds (1.2%), Black Caribbean (1%), Black Africans (0.8 %), Bangladeshis‟ (0.5%) and Chinese (0.4%). The remaining minority ethnic groups each accounted for less than 0.5% of the UK population and together accounted for a further 0.9%. The numbers and proportions of older people from BME groups

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are rising and will continue to rise for the foreseeable future. However, people from BME groups have a slightly younger age profile. Nine per cent of people from Black and Caribbean ethnic backgrounds are aged 65 and over and six percent of Indians are aged 65 and over. These proportions are expected to expand as people from minority ethnic groups who migrated to the UK in the 1960s and 1970s reach retirement age (ONS, 2003).

Unfortunately there is no data which breaks down the incidence of AD, VaD or any other dementia type illness within BME groups. It is hypothesised that the incidence of VaD would be higher for BME groups since they are a high risk for developing cardiovascular- related difficulties (Chen, 2004; Purandare, Luthra, Swarbrick & Burns, 2007).

1.2.4 Literacy and fluency of English language amongst ethnic minority groups in the UK

One barrier to implementing routine practices for minority ethnic groups is language. There are no consistent or conclusive statistics for rates of literacy and fluency in English within minority ethnic groups. Within migrant groups, older people are least likely to have acquired faculty in the dominant language and integrated into the new nation‟s culture (Johnson, Owen, Blackburn, Rehman & Nazroo, 2000). In a 1999 survey, among the 50 to 74 age group, 67% of Pakistani women, 46% of Pakistani men, 100% of Bangladeshi women and 64% of Bangladeshi men stated they could speak „only a little English‟ (Johnson et al, 2000).

In addition, cognitive testing relies on linguistic competence. Therefore, whether a person understands English or not, tests which are reliant on spoken language to assess cognitive functioning, would limit their usefulness with those who are non-verbal in general. For non-English speakers, clinicians may be dependent on an interpreter;

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however, interpreting test instructions is simpler to do than interpreting verbal responses. The reason being that the test responses are the main source of measurement and changing requirements for verbal responses to make them more culturally specific may cause them to be less equivalent to the original test designed for English speakers. Therefore, measures that are not reliant on spoken language can assist the patient to communicate their responses by drawing or pointing to answers (Olsson, 2004).