Global burden of dementia estimated
medwireNews: The number of people living with dementia globally has more than doubled between 1990 and 2016, estimates the Global Burden of Disease (GBD) Study 2016.
This is mainly due to population ageing and growth, report Emma Nichols (University of Washington, Seattle, USA) and fellow GBD 2016 Dementia collaborators in The Lancet Neurology.
They analysed data on dementia from 237 scientific literature sources covering 195 countries and territories from 1990 to 2016 and found that 43.8 million people globally were living with dementia in 2016. This was an increase of 117% from the 20.2 million living with the condition in 1990.
However, during this time the global age-standardised prevalence remained fairly stable, increasing by just 1.7%, from 701 cases per 100,000 people in 1990 to 712 cases per 100,000 people in 2016.
“[W]ithout a major scientific breakthrough the continuation of sweeping demographic trends in population ageing and growth will lead to further increases in the number of people living with dementia”, says the team.
More women than men had dementia in 2016 (27.0 vs 16.8 million), with the age-standardised prevalence 1.7% higher.
And the researchers report that dementia was the fifth leading cause of mortality in 2016, accounting for 2.4 million deaths. Dementia was also associated with 28.8 million disability-adjusted life–years (DALYs), and of these 6.4 million could be attributed to the modifiable risk factors of high BMI, high fasting plasma glucose levels, smoking and a high intake of sugar-sweetened beverages.
Nichols and colleagues highlight, however, that their analysis identified “substantial heterogeneity in case-ascertainment methods throughout the dementia literature, highlighting the need for more consistency in future research.”
Indeed, in a related comment, Lenore Launer, from the National Institute on Aging in Bethesda, Maryland, USA, says that “[f]rom a public health and disease-prevention perspective, too few quality data are available for dementia that fit the complex reality of this devastating public health problem.”
She continues: “[I]t is questionable whether the extant data are strong enough to help achieve the goals of this GBD study—to inform policy makers, researchers, and clinicians about global differences in dementia trends, clusters of dementia, and causal risk factors.”
Launer believes that to reach these goals it will take stronger data collection and better interpretation alongside improved research methods, a consensus over valid administration coding and flexible approaches to account for the variable health and social conditions in different countries over time that might lead to cognitive impairment.
By Lucy Piper
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