Alzheimer disease: progress or profit?

Alzheimer disease is the most common cause of dementia. According to the World Health Organization, an estimated 37 million people worldwide currently have dementia; Alzheimer disease affects about 18 million of them1. Increasing age is the greatest risk factor for Alzheimer disease. Its prevalence approximately doubles every five years after the age of 60—one in 10 individuals over 65 years and nearly half of those over 85 are affected by the disease. So, although the incidence rate of Alzheimer disease is not thought to be changing, Alzheimer disease poses one of the greatest threats to the future of healthcare systems, owing to the anticipated demographic shift to an aging population—the number of people worldwide above the age of 60 years is expected to double over the next 25 years. The Alzheimer’s Society (Alzheimer’s Society Policy Positions Paper—Demography, http://www.alzheimers.org.uk/News_and_ campaigns/Policy_watch/demography.htm; ref. 2) estimates that the number of individuals with Alzheimer disease will almost double to 34 million by 2025, with just less than 1 million new cases per year by 2050 (Fig. 1). Notably, developing countries are expected to see the biggest increase in population and life expectancy. According the Alzheimer’s Association3, between 1990 and 2010 the number of people aged 65 years or over in developing countries is projected to increase by 78%—from 183 million to 325 million.