Four modifiable risk factors are responsible for the big jump in the number of people suffering from dementia worldwide, according to new research.
The incidence of dementia globally more than doubled between 1990 and 2016, from 20.2 million in 1990 to 43.8 million in 2016, a new paper published in The Lancet Neurology reports. And researchers want more preventative action.
The study, Global, regional, and national burden of Alzheimer’s disease and other dementias, 1990–2016, was prepared by academics from several institutions and led by the University of Melbourne and the University of Washington.
It found that more women than men had dementia in 2016 (27 million vs 16.8 million), that dementia was the fifth leading cause of death globally and that prevalence doubled every five years after age 50.
Strikingly, it found that the 22.3 per cent of healthy years lost due to dementia in 2016 were due to modifiable risk factors.
The authors said: “In our study, 22.3 per cent of the total global disability-adjusted life years lost due to dementia in 2016 could be attributed to the four modifiable risk factors – being overweight, high blood sugar, consuming a lot of sugar-sweetened beverages and smoking.”
University of Melbourne lead author Professor Cassandra Szoeke said even more risk factors would be explored in the new data collection.
“But already the importance of these risks in allowing us to prevent or delay dementia is clear,” she said. “The paper noted that changes in risk factor exposure over time as we become healthier might account for several cohort studies documenting a reduction in age-specific incidence rates …”
Prof. Szoeke said that because dementia developed at least 20 to 30 years before it could be diagnosed, studies needed to investigate cognition over 20 to 30 years to determine when and for how long intervention was needed to prevent the disease.
Most randomised controlled trials lasted one to five years, she said, with 30-year longitudinal studies rare.
“In addition, when you look over decades, there are so many exposures that impact on our health,” she said. “You need to account for all these things or you could miss a factor that is crucial in the development of disease.”
Prof. Szoeke said that by 2050, 100 million people would be living with dementia.
“The paper states that to support our community, we will need a larger workforce of trained health professionals as well as … facilities and community-based services that support improved quality of life.
“We need to enhance the quality of life and function of people living with cognitive impairment and focus on preventing further cognitive decline. This will need a co-developed community-wide approach with well-developed services and an even greater network of trained health professionals.
“Chronic diseases are becoming the leading causes of death and disability worldwide, and while we continue to work daily on new therapies to target disease, at home we really need to focus more on the health choices that we know extend both disease-free and disability-free survival.”
Are you aware of the four key risk factors involved in dementia? Did you know that onset starts 20 to 30 years before the disease becomes recognisable?