3 ms·
From the article... "1 percent of 65-year-olds, 2 percent of 68-year-olds, 3 percent of 70-year-olds. After that, the odds start multiplying. The likelihood of
by jqm 12y ago
From the article...
"1 percent of 65-year-olds, 2 percent of 68-year-olds, 3 percent of 70-year-olds. After that, the odds start multiplying. The likelihood of your developing Alzheimer’s more or less doubles every five years past 65. Should you make it to 85, you will have, roughly, a fifty-fifty shot at remaining sane."
1% at 65 doubling every 5 years for 20 years = 16%
3% at 70 doubling every 5 years for 15 years = 24%
What am I missing?
- Someone 12y agoThe "likelihood of developing" vs incidence (what proportion of population suffers from it) 1% at 65, 3% at 70 means that, in the 65-70 year range, about .4% of that cohort develops Alzheimer's per year. Double that to .8% per year in the 70-75 year range and you get 7% incidence at age 75 (3% had it at age 70, 4% got it between ages 70 and 75). Continuing, you get: - 1.6%/year in the 70-75 range gives you 15% incidence - 3.2%/year in the 75-80 range gives you 31% incidence - 6.4%/year in the 80-85 range gives you 63% incidence That's in the right ballpark.
- jqm 12y agoDidn't you use 70-75% twice? Once in the text body and once in the list? Wouldn't your method leave you with 31% at the end if you just used this age bracket once and didn't have the extra double cycle? But for the record, I'm sure you are right. The ODDS of developing start doubling. Not the amount of people afflicted (No doubt a somewhat complicated figure as death, not insignificant at those ages, starts changing the equation. Do people with Alzheimer die at the same rate as those without?). Thanks for the explanation.