Q: My grandmother is 87. So many of her friends have died and she isn’t as physically strong as she used to be, so she doesn’t get out much. I’m worried that her world is shrinking and that’s going to make it harder for her to stay healthy. What should I do to help? — Katie W., Iowa City, Iowa A: You’re a smart granddaughter! You have mentioned the very risk factors for dementia, disability and death that recent research identifies. In the study, published in JAMA Network Open, researchers found that as social and physical isolation increase so does the occurrence of cognition problems, Alzhe…