This post contains the published figures and calculations I used to compare Alzheimer's and dementia rates in the US versus the UK:
*The Alzheimer's Association web site gives an estimate for the prevalence of Alzheimer's in the US: "One in 10 individuals over 65 and nearly half of those over 85 are affected."
*Across the Atlantic, the Alzheimer's Society estimates 750,000 people in the UK have dementia, and 732,000 of them are 65 and older.
*The UK's National Statistics Online shows that in 2004, 16% [or about 9.6 million] of the 59.8 million people in the UK were 65 and older.
*If 732,000 of the 9.6 million people over 65 in the UK have dementia, that's about 7.7%.
*The Alzheimer's Society estimates that Alzheimer's disease accounts for about 55% of dementias in the UK. By extension, if 7.65% of the over 65 population has dementia, then 55% of that 7.65%, or 4.2% have Alzheimer's.
*The Alzheimer's Assocation says Alzheimer's disease accounts for 60% to 70% of all dementias in the US. Using the 60% figure, then if 10% of people over 65 in the US have Alzheimer's disease, 16.7% would have dementia. Using the 70% figure would mean that 14.3% of people over 65 would have demention. With rounding, this implies that somewhere between 14% and 17% of people over 65 in the US have dementia.