Dementia more preventable in Asia and Latin America

News Release
April 2019 | University College London, Gower Street, London – Dementia more preventable in Asia and Latin America

Close to one in two cases of dementia could be preventable in low- to middle-income countries, finds a new UCL study.

Dancing in Peru
The findings, published in The Lancet Global Health, found how improving childhood education and other health outcomes throughout life could reduce the risk of dementia.

“After our previous research finding that one in three cases of dementia could be preventable, we realised that the evidence was skewed towards higher-income countries,” said the study’s lead author, Dr Naaheed Mukadam (UCL Psychiatry).

“We have now found that in low- to middle-income countries in Asia and Latin America, dementia may be even more preventable than it is in more wealthy countries. If life-course risk factors such as low levels of education in early life and hearing loss, obesity and low physical activity in mid-life to old age are addressed, these countries could see large improvements in their dementia rates.”

While the number of people with dementia is increasing globally, particularly in low- to middle-income countries, there have been modest reductions in age-specific dementia rates in many high-income countries over the last two decades.* The researchers say this could be due to improvements in health outcomes throughout life that affect dementia risk.

The research team built on their previous work for the Lancet Commission on dementia prevention, intervention, and care, published in 2017, which found that 35% of dementia is attributable to nine risk factors: low levels of childhood education, hearing loss, smoking, hypertension, obesity, physical inactivity, social isolation, depression, and diabetes.*

To understand whether the commission’s findings would apply equally to global regions that were underrepresented in the report, a team of UCL researchers sought out data from China, India and Latin America. They drew from the research collective 10/66 Dementia Research Group’s data, which used similar methodology to gauge prevalence of the nine risk factors in those countries, with sample sizes of 1,000 to 3,000 in each country.

The researchers found even more potential for preventing dementia across the globe, as the proportion of dementia linked to the nine modifiable risk factors was 40% in China, 41% in India and 56% in Latin America.

A major factor in that difference is the lower levels of educational attainment in low- to middle-income countries, which the researchers say signals hope for the future, as education levels rise.

“People growing up in Asia and Latin America today are more likely to have completed schooling than their parents and grandparents were, meaning they should be less at risk of dementia later in life than people who are already over 65. Continuing to improve access to education could reap great benefits for dementia rates in years to come,” Dr Mukadam said.

On the other hand, social isolation is a major risk factor of dementia in higher income countries, but much less so in China and Latin America. The researchers say that public health officials in countries such as the UK could learn from China and Latin America in efforts to build more connected communities to buffer against the dementia risk tied to social isolation.

Obesity and hearing loss in mid-life, and physical activity in later life, were also strongly linked to dementia risk in the study area, as well as mid-life hypertension in China and Latin America and smoking in later-life in India.

“Reducing the prevalence of all of these risk factors clearly has numerous health benefits, so here we’ve identified an added incentive to support public health interventions that could also reduce dementia rates. The growing global health burden of dementia is an urgent priority, so anything that could reduce dementia risk could have immense social and economic benefit,” Dr Mukadam said.

Senior author Professor Gill Livingston (UCL Psychiatry) added: “A lot of the findings of health and medical research derive primarily from higher income countries such as in Western Europe and North America, so ensuring that research is inclusive is vital to the development of global public health strategies.”

“While we don’t expect these risk factors to be eliminated entirely, even modest improvements could have immense impact on dementia rates. Delaying the onset of dementia by just five years would halve its prevalence*,” she said.

The researchers are supported by the National Institute for Health Research UCLH Biomedical Research Centre, Wellcome, NIHR, Economic and Social Research Council, and NIHR Collaboration for Leadership in Applied Health Research and Care North Thames.

Links
Research paper in The Lancet Global Health
Dr Naaheed Mukadam’s academic profile
UCL Psychiatry
* The Lancet Commission on dementia, prevention, intervention and care
Image
People dancing in Peru. Credit: Alex Proimos, Source: Flickr
Media contact
Chris Lane
tel: +44 20 7679 9222

E: chris.lane [at] ucl.ac.uk

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The impact on Green Spaces on your Child’s Brain Health

Press Release
February 2018 | Aarhus University – Being surrounded by green space in childhood may improve mental health of adults by Peter Bondo

Being surrounded by green space in childhood may improve mental health of adults

Children who grow up with greener surroundings have up to 55% less risk of developing various mental disorders later in life. This is shown by a new study from Aarhus University, emphasizing the need for designing green and healthy cities for the future.

[Translate to English:]  Et nyt studie fra Aarhus universitet viser at børn, der vokser op med grønne omgivelser har op til 55% mindre risiko for at udvikle en psykisk lidelse senere i livet. Ifølge forskerne er integration af grønne omgivelser i byplanlægning vigtigt for at sikre grønne og sunde byer for eftertidens generationer. Modelfoto: Colourbox.dk

A new study from Aarhus University shows that children who grow up surrounded by high amounts of green space have up to 55% less risk of developing a mental disorder later in life. According to the researchers, integration of green space in urban planning is important to ensure green and healthy cities for the future generations. Model photo: Colourbox.dk.

A larger and larger share of the world’s population now lives in cities and WHO estimates that more than 450 millions of the global human population suffer from a mental disorder. A number that is expected to increase.

Now, based on satellite data from 1985 to 2013, researchers from Aarhus University have mapped the presence of green space around the childhood homes of almost one million Danes and compared this data with the risk of developing one of 16 different mental disorders later in life.

The study, which is published today in the prestigious American Journal PNAS, shows that children surrounded by the high amounts of green space in childhood have up to a 55% lower risk of developing a mental disorder – even after adjusting for other known risk factors such as socio-economic status, urbanization, and the family history of mental disorders.

The entire childhood must be green

Postdoc Kristine Engemann from Department of Bioscience and the National Centre for Register-based Research at Aarhus University, who spearheaded the study, says: “Our data is unique. We have had the opportunity to use a massive amount of data from Danish registers of, among other things, residential location and disease diagnoses and compare it with satellite images revealing the extent of green space surrounding each individual when growing up.”

Researchers know that, for example, noise, air pollution, infections and poor socio-economic conditions increase the risk of developing a mental disorder. Conversely, other studies have shown that more green space in the local area creates greater social cohesion and increases people’s physical activity level and that it can improve children’s cognitive development. These are all factors that may have an impact on people’s mental health.

“With our dataset, we show that the risk of developing a mental disorder decreases incrementally the longer you have been surrounded by green space from birth and up to the age of 10. Green space throughout childhood is therefore extremely important,” Kristine Engemann explains.

Green and healthy cities

As the researchers adjusted for other known risk factors of developing a mental disorder, they see their findings as a robust indication of a close relationship between green space, urban life, and mental disorders.

Kristine Engemann says: “There is increasing evidence that the natural environment plays a larger role for mental health than previously thought. Our study is important in giving us a better understanding of its importance across the broader population.”

This knowledge has important implications for sustainable urban planning. Not least because a larger and larger proportion of the world’s population lives in cities.

“The coupling between mental health and access to green space in your local area is something that should be considered even more in urban planning to ensure greener and healthier cities and improve mental health of urban residents in the future,” adds co-author Professor Jens-Christian Svenning from the Department of Bioscience, Aarhus University.

Further information:

Postdoc Kristine Engemann, Centre for Biodiversity Dynamics in a Changing World (BIOCHANGE) & Section for Ecoinformatics and Biodiversity, Department of Bioscience, Aarhus University, and The National Centre for Register-based Research, Department of Economics and Business, Aarhus BSS, Aarhus University. E-mail: engemann@bios.au.dk. Tel.: + 45 25368404.

Professor Carsten Bøcker Pedersen, The National Centre for Register-based Research, Department of Economics and Business, Aarhus BSS, Aarhus University. E-mail: cbp@econ.au.dk. Tel.: + 45 87165759.

Professor Jens-Christian Svenning, Centre for Biodiversity Dynamics in a Changing World (BIOCHANGE) & Section for Ecoinformatics & Biodiversity, Department of Bioscience, Aarhus University. E-mail: svenning@bios.au.dk. Tel.: 45+ 28992304.

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