First, I'm not a doctor so you should check with your family physician. As I understand it, there may be a hereditary connection just like heart disease, high cholesterol and other health factors. The more relatives you have with the disease, the more chance of developing it. HOWEVER, there are many other factors. The chance of developing it increases with age. There are all kinds of statistics on the internet as to the high number of people age 85+ who have the disease. Second, the profile for early-onset Alzheimers' cases (defined as before age 65) is different, and shows a much stronger genetic linkage.
Information is constantly being reported on possible risk factors. Keep in mind that books may report on info that is 2+ years old, due to the lead time for writing, editing, publishing and distribution. You will find additional, current info on the AD websites.
In my family it skips a generation and seems to affect the oldest female. In my case that would make me next. We have traced it back several generations just to see if it had hereditary evidence. Sadly I am now disabled at 37 due to a head injury. Since I also have multiple concussion syndrome my docs say I have a high likely hood of developing it as I now suffer from short term memory loss, and cognitive issues as well as mood disorder due to my latest injury. Sadly my 13 year old son is terrified of watching me like this and I try and reassure him that I am fine right now. He watched his Yaya (my mama) die from cancer that eventually went to her brain and caused dementia and then for 4 more years my Nana decline and eventually die from AD. It terrifies me to think of being that bad off, and I am trying to put some stop gaps in place should I continue to deteriorate. It is always a good idea to do at least a 5 generational health history if you can. My family has always been big on tracing family history so it was not difficult for me to find the info I needed.
The way I explain it to sufferer's of this disease is:
You've been alive XX amount of years.
Your brain is FULL and can't remember new memories
I'm not that far off the truth really .. it doesn't mean it's hereditary either. SOME dementia's ARE hereditary, and you can go for genetic marker testing to see if it could be possible for you. Speculating is stressfull and pointless. Get your facts THEN act on the results.
Remember, the longer we live, the more likely we WILL get some form of dementia .. old age onset or whatever.
I believe it can be but a secret little part of me says "Please God don't let it be" because my dad has it, my mom's sister has it, mom's mom had it, dad's dad had it and we believe dad's brother has it. My mother, I believe, was spared it only because she died at 67 of heart disease and COPD.
Am I afraid I might someday develop it? Of course I am. Do I worry about my son? It's in my husband's family too so you bet I worry about him and my husband. But I hold on tight to that thread of hope. First the hope that experts will find a way to positively identify and accurately diagnose AD/dementia before death. (AD at this point can positively be diagnosed only thru autopsy). Then I believe that a cure can be found.
In the meantime, I'm living my life the best way I can. I try to take care of myself and enjoy the life I have now.
I always thought it was hereditary too, but earlier this year i saw a doctor talking about it on TV and he said it's not actually hereditary, only if there are alot of family members with it and they are under the age of 40. In other words, if there are alot of your family members with it over the age of 40, it's just co-incidence.