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The 10/66 Group: Getting to grips with dementia

21 Sep, 2010
Brain falling apart into sky - artwork

Brain falling apart into sky – artwork

The 10/66 Dementia Research Group is a collective researching the impact of dementia in Africa, Asia and South America.

While 66 per cent of people with dementia around the world live in low- and middle-income countries, less than 10 per cent of all population-based research into the disease has been carried out in these regions.

The 10/66 Dementia Research Group (its name referring to that imbalance) is a collective of research groups throughout Africa, Asia and South America coordinated by Professor Martin Prince at the Institute of Psychiatry at King’s College London, that is generating evidence on the prevalence and impact of dementia in those regions.

Dementia tends to be seen as a disease of richer countries, with studies, until recently, indicating it was much less of a problem in low and middle-income countries. Indeed, estimates using standard diagnostic criteria suggested that dementia prevalence in these regions is only a quarter or a fifth of what it is in high-income countries.

However, the standard criteria for diagnosis (termed DSM-IV) used for such estimates were developed for people in the West – whose culture, education, lifestyle and notions of what constitutes daily functioning may be dramatically different from those in low- and middle-income countries. The low prevalence found in those regions may therefore have been under-estimated. Without rigorous epidemiological research, using a cross-culturally valid diagnostic interview, it is impossible to quantify the problem and plan adequate investment in future services to address it.

To address this research gap, in 1988 researchers at the annual conference of Alzheimer’s Disease International in Cochin, India, decided to pool their resources – and the 10/66 Dementia Research Group was born.

Developing a new assessment

The first step was to develop a method for assessing older people’s cognitive functioning so that the evaluation would be valid across different cultures and levels of education. This is important, because sometimes people may not have the knowledge to answer a particular question or it may not be culturally relevant, in which case they could be misdiagnosed with dementia.

“People from less developed, rural areas may not know what year it is – a classic question to test for dementia in the developed world – because they don’t need to. They would, however, be aware of changing seasons,” says Professor Prince.

The 10/66 team developed an ‘education and culture-fair’ assessment for dementia, which was then translated into local languages and tested in 26 centres from India, China, South-east Asia, Latin America and the Caribbean; over 3000 people were assessed. The results showed that the ’10/66 Dementia Diagnosis’ was accurate and valid for all participating countries, languages, cultures and education levels, and that the data were comparable between them.

Population studies

Next, the team embarked on a series of large-scale population surveys of dementia prevalence using the 10/66 Dementia Diagnosis, with funding from a number of organisations including a Wellcome Trust project grant that supported studies in Cuba and Brazil. They surveyed around 2000 people aged 65 and over within geographically defined catchment areas in 11 countries, resulting in a total sample size of over 20 000.

These surveys used both the 10/66 diagnosis and the DSM-IV criteria in order to compare the two assessments. The 10/66 diagnoses identified more cases of dementia in all countries than the DSM-IV criteria, and the numbers were also more consistent across sites. The researchers found evidence that the DSM-IV method tended to miss mild to moderate cases of dementia, and that dementia prevalence in low- and middle-income countries is likely to be higher than previously thought, and much closer to that seen in the West.

Among the factors contributing to the original low figure is the fact that parents in low- and middle-income countries often live with their children, who routinely provide them with support and care, so problems in daily life because of dementia are less likely to be noticed than they would in London, for example. This is exacerbated by a lack of understanding of dementia as an organic brain disease. “Loss of memory is seen as a normal part of ageing, so families don’t report it,” says Professor Prince. The culture of respect and veneration of older people in some traditional settings, he says, is also likely to make family members reluctant to report impairment or decline, as this might be seen as criticism or judgement.

Illustration depicting the pathology of Alzheimer’s disease.

Illustration depicting the pathology of Alzheimer’s disease.

Helping carers to care

Another priority for the 10/66 team was to look at care arrangements for people with dementia, and the impact of the diseases on caregivers, health services and the wider community. The pilot study found that caregivers across the world experience similar levels of strain, and many in low- and middle-income countries have to cut back on work or pay to care for their elderly relatives.

This prompted the 10/66 researchers to develop and trial a programme aimed at easing the burden on carers called ‘Helping Carers to Care’. It uses community-based health workers who, after a few sessions of training, can identify cases of dementia in their catchment area, and explain to the carer that it is an organic brain disease.

“Carers can be stigmatised because neighbours think the parent’s behaviour is due to abuse or neglect at home. Or they might blame the person with dementia for being lazy, difficult, feckless and contradictory,” says Professor Prince.

“Explaining that this is a medical condition can change what is going on at home in important ways, and improve both parties’ quality of life.” The health workers can also tell carers what to expect so that they can plan ahead to get help when they need it, and offer advice on dealing with particular behavioural or psychological problems such as agitation, delusions or wandering off.

The results of the ‘Helping Carers to Care’ randomised controlled trials have shown that intervention in resource-poor countries is even more effective than it tends to be in the West, where awareness of dementia as a medical condition is already high. “It makes a critical difference in the home, to relationships and understanding,” says Professor Prince. “It’s one of the most important parts of our programme.”

Elderly woman with carers in Thailand.

Elderly woman with carers in Thailand.

Predicting dementia

It was important to ensure that the original diagnosis was sensitive to early-stage dementia, where there is mild cognitive impairment but as yet little or no impact on function. Having established a much higher prevalence of dementia using 10/66, the next step was to test its ‘predictive validity’ as a diagnostic tool.

“We know that dementia is a progressive neurodegenerative disorder, so we can predict that people diagnosed with dementia in the population survey will experience worsening cognitive and functional decline and greater levels of dependency two to three years later,” says Professor Prince.

This third phase of the 10/66 research studies was therefore a series of follow-up studies identified in case studies of the populations in Latin America and China. These studies – supported by a five-year Wellcome Trust programme grant – are still ongoing.

Results from the first centre to complete the study, in India, showed a three times higher mortality rate in those with dementia, and clear signs of progression among almost all survivors. These findings show that the 10/66 test has strong predictive validity. Identifying cases early will mean carers can be prepared earlier on to deal with an older person’s future decline.

The data collected from the population and incidence studies are freely available to the wider research community (under a monitored open-access policy, with all information regarding the simple application procedure available at the project website), and comprises a unique database of directly comparable data on over 20 000 older adults from three continents.

The project also collected information on a wide range of risk factors leading to dementia and the links it has with different diseases, such as cardiovascular disease. “The incidence data are crucial,” says Professor Prince. “The researchers got all the information on genes, health status and lifestyle at the start, during the baseline population study. Now they can follow it up, look at the change over time, and start to tease out the chicken and the egg. Who gets the diseases three years down the line? What did the original assessments say about their genes and lifestyles and which of these might be risk factors?”

Making policy

The 10/66 group is already looking at ways to ensure that its research findings help improve the lives of elderly people. “Dementia and stroke are a low priority in low-income countries, which tend to prioritise diseases according to the mortality rate,” points out Professor Prince.

“We want to highlight the years lived with disability and the extent to which caretakers are tied up with care – and make sure that dementia is on the list of conditions needing attention. That’s why it’s so important to generate evidence in the first place – so that policy makers and advocates can use it to make sure there are health service improvements that meet the real needs of the public.”

Alzheimer’s Disease International, working with 10/66, has produced a World Alzheimer’s Report in two parts. “It will contain all the relevant information that a policy maker would need to understand dementia in a developing country – the numbers, impact, access to health services and implications for future health systems,” says Professor Prince. “10/66 data are an important part of that due to the paucity of evidence in those regions.”

Part One of the report was launched in New York on World Alzheimer’s Day on 21 September 2009. The world’s news media extensively reported the headline finding that there would be 35 million people with dementia in 2010, rising to 115m by 2050 with most of the increase occurring in low- and middle-income countries.

Part Two, focusing on the global societal cost of dementia, is released on World Alzheimer’s Day 2010. This shows that the global cost of dementia exceeds US$600 billion, amounting to just over 1 per cent of global gross domestic product.

Costs tend to be lower in low-income countries, where they mainly arise from the inputs of unpaid family carers. In high-income countries, the major cost driver is the cost of social care in the community and residential care homes. Costs are set to increase dramatically worldwide, but particularly in low- and middle-income countries, as the numbers affected increase rapidly, and the ability of families to shoulder the burden of care is compromised. These reports can be downloaded from Alzheimer’s Disease International.

Finally, having established the simplicity, feasibility, effectiveness and low cost of the ‘Helping Carers to Care’ intervention for community workers, 10/66 is now working with the WHO’s Mental Health Global Action Plan to encourage developing countries to contribute to the design and guidelines for the management of dementia by non-specialists in primary care – and for modified interventions targeting dependency across all chronic conditions.

Although awareness of the importance of dementia in low- and middle-income countries is now growing, Professor Prince cautions that much more research is needed to close the 10/66 gap.


Sousa RM et al. Contribution of chronic diseases to disability in elderly people in countries with low and middle incomes: a 10/66 Dementia Research Group population-based survey. Lancet 2009;374(9704):1821-30.

Prince MJ et al. Packages of care for dementia in low- and middle-income countries. PLoS Med 2009;6(11):e1000176.

Llibre Rodriguez JJ et al. Prevalence of dementia in Latin America, India, and China: a population-based cross-sectional survey. Lancet 2008;372(9637):464-74.

Ferri CP et al. for Alzheimer’s Disease International. Global prevalence of dementia: a Delphi consensus study. Lancet 2005;366(9503):2112-17.

Prince M et al. Dementia diagnosis in developing countries: a cross-cultural validation study. Lancet 2003;361(9361):909-17.

Image credits: Heidi Cartwright, Wellcome Images, Medical Art Service, Munich/Wellcome Images.
2 Comments leave one →
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