An analysis of the Global Burden of Disease (GBD) Study 2013, published in The Lancet (December 17, 2014), has found that Alzheimer’s disease was responsible for 52 per cent more deaths in 2013 compared to 1990.

The research showed that the number of UK deaths from Alzheimer’s rose from 32,429 in 1990 to 49,349 in 2013.

Global Burden of Disease Study 2013 collaborators (2013) Global, regional, and national age–sex specific all-cause and cause-specific mortality for 240 causes of death, 1990–2013: a systematic analysis for the Global Burden of Disease Study 2013. The Lancet, Vol. 385, No. 9963, p117–17. https://www.thelancet.com/journals/lancet/article/PIIS0140-6736%2814%2961682-2/fulltext

The researchers used a substantially different approach to estimate Alzheimer’s disease and other dementia mortality in the GBD 2013 compared to the GBD 2010. They focussed on studies of prevalence and using data from countries with the highest death to prevalence ratios in 2013 to estimate mortality in other regions and back in time.

This change greatly lowers the increase compared with GBD 2010 in the age-standardised death rate for dementia although the numbers of dementia deaths nevertheless increased. Lower increases in the age-standardised rate were because the meta-regression of prevalence studies did not show a rapidly rising trend; one study, reported decreases in age-specific rates, although our overall assessment suggests a slight increase in age-specific rates. The researchers argue that dementia was systematically underestimated as a cause of death in earlier periods.

The other effect of using this approach is that the researchers estimated considerably more dementia deaths in middle-income countries than in the GBD 2010. Prevalence studies suggest dementia occurs in these countries although it is rarely recorded on a death certificate as a cause of death. The overall conclusion is that dementia is more common worldwide and that numbers are increasing because of population ageing with only a small component of the increase caused by rising age-specific rates.

The research finding that the number of dementia deaths is increasing implies that governments should remain concerned about the rising demands for care that will come with population ageing even if future rates do not increase substantially.