A study by an international team of researchers from University College London and the University of Liverpool published in The BMJ predicts that dementia will affect more than 1.2 million people in England and Wales by 2040.
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The researchers, who aimed to forecast the burden of dementia, say that this increase of 57% from 2017 is due to people living longer. With £23 billion as the present estimated cost of dementia to the UK economy, accurate projections are critical for defining future needs. However, existing predictions presume the rate of dementia to be stable and hence may not be precise.
Thus, the study team framed a mathematical model (IMPACT—Better Ageing Model) that took into account the trends of the disease, the death rates, and the effects of increasing life expectancy for a more accurate prediction of the future burden.
Data from 18,000 men and women from the English Longitudinal Study of Ageing (ELSA) were used in the research. ELSA was started in 2002 for tracking the health of a representative sample in England aged 50 and above.
Random selection of participants was done in six waves from 2002 to 2013. Tests to evaluate memory, verbal fluency, numeracy function, and basic life activities (e.g., getting in or out of bed, dressing, and eating) were conducted at every wave. Dementia was identified by these assessments, and was complemented by a doctor’s diagnosis or through interviews with carers.
The team after resolving the effects of dropouts from the study found a decline in the rate of dementia by 2.7% per year between 2002 and 2013.
Based on the results, the researchers conclude that the number of newly diagnosed cases of dementia has decreased however there is a substantial increase in the number of people living with the condition due to increased life expectancy and declined number of deaths by other causes like heart diseases.
There are currently 800,000 people in England and Wales with dementia, but this could increase to over 1.2 million by 2040, based on the calculations in the study.
“The risk of developing dementia at any given age is going down over time, shifting dementia to later years in life,” says Dr. Sara Ahmadi-Abhari, lead author from University College London.
“This decline is mainly because of improvements in healthcare and adopting healthier lifestyles. Our estimate of 1.2 million people with dementia by 2040 is based on the assumption that the decline in risk of developing dementia continues to the future.” She also adds that if public health efforts fail and the risk of developing dementia does not continue to decline, the growth in numbers of people living with dementia will be much larger, reaching 1.9 million by 2040.
Although the authors list a few study limitations that might have induced bias, Professor Eric Brunner, the senior investigator remarks:
Our results have significant policy implications in terms of care needs and public spending and act as a benchmark to measure the impact of possible dementia prevention initiatives.”
Emiliano Albanese at the University of Geneva, also added that the study confirms the need for high-quality epidemiological studies in monitoring the actual changes in dementia prevalence, incidence, and associated mortality over time.