More than 26 million people worldwide are living with Alzheimer's disease, but that number is set to quadruple by 2050, according to researchers from Johns Hopkins University in the USA.

"We face a looming global epidemic of Alzheimer's disease as the world's population ages," said the study's lead author, Ron Brookmeyer, as the findings were presented at the Alzheimer's Association International Conference on Prevention of Dementia in Washington DC and published in its journal, Alzheimer's & Dementia. The global prevalence of Alzheimer's disease will exceed more than 106 million cases by 2050 and by that time, 43% of those with Alzheimer's disease will need high-level care, equivalent to that of a nursing home.

Professor Brookmeyer noted that by 2050, one in 85 people will be suffering from the condition but “if we can make even modest advances in preventing Alzheimer's disease or delay its progression, we could have a huge global public health impact." Specificially the report, which was funded by Elan and Wyeth, noted that interventions that could delay the onset of Alzheimer's disease by as little as one year would reduce its prevalence by 12 million fewer cases in 2050.

A similar delay in both the onset and progression of Alzheimer's disease would result in a smaller overall reduction of 9.2 million cases by 2050, because slower disease progression would mean more people surviving with early-stage disease symptoms. However, nearly all of that decline would be attributable to decreases in those needing costly late-stage disease treatment, the study argues.

The largest increase is expected to occur in Asia, which currently accounts for 48% of the world's patients. The number of Alzheimer's cases is expected to grow there from almost 13 million in 2006 to nearly 63 million in 2050, making up 59% of total cases of the world's Alzheimer's cases will live in Asia. Cases in Europe will jump 130% to 16.5 million, while North America will rise to 8.8 million from 3.1 million.

DiaGenic’s blood-based diagnostic shows promise

It may look like a depressing picture but companies are still searching for treatments, notably Elan and Wyeth which recently announced that they are going to initiate a late-stage trial for AAB-001 (bapineuzumab), their new Alzheimer's disease treatment way ahead of schedule. Early diagnosis is also vital, which is why data from a simple blood test pioneered by a Norwegian biotechnology firm caused much excitement at the conference.

DiaGenic presented the prototype of, and results of initial trials from, a blood-based diagnostic test and its chief executive Erik Christensen commented that the results revealed in Washington DC show that “the test can detect Alzheimer’s disease with a clinically acceptable accuracy of above 80%.” DiaGenic now aims to make the test available in early 2008.