Ryan Libbey has opened up about his heartbreak over his grandparents’ Alzheimer’s diagnoses as he prepares to run the New York Marathon in their honour.The Made In Chelsea star, 36, lost his former Marine grandfather Tom to the disease aged 80, while his grandma Christine, 85, is currently in the most advanced stages.Ryan, who shares son Leo, four, with his fiancé Louise Thompson, is raising £25,000 for Alzheimer’s Society ahead of the gruelling challenge next month.The fitness fanatic has shared his fears over one day inheriting the disease after two of his grandparents were diagnosed.In an interview with the Daily Mail, Ryan explained: ‘Sadly, my grandma is probably in, I don’t want to say final stages, that sounds really negative and fatalistic, but that’s probably the harsh reality. I don’t know if it can get much worse. ‘She’s been suffering for quite some time now, and I feel like the disease has got the tightest grip on her. She has no idea who we are. Everyone experiences dementia differently. Use this checklist to help you make a note of your symptoms before you talk to your GP. Ryan Libbey, 36, has opened up about his heartbreak over his grandparents’ Alzheimer’s diagnoses as he prepares to run the NYC Marathon in their honour (pictured with nan Christine) The Made In Chelsea star lost his grandfather Tom (pictured), who was a former Marine, to the disease aged 80, while his grandma Christine, 85, is currently in the most advanced stages’She can barely function with her speech or actually any functions at all. She is fully supported in every way and that’s the scary part of it.’Sharing his ‘hero’ grandad’s story, he said: ‘I lost my grandad in 2015, he was probably my first male role model and hero. He was a Marine and he was an international athlete. ‘He was just this full of life, fit, physically fit, and just an able, loving, sensitive man, and then he basically lost all communication between brain and body, so he ended up basically swallowing his own tongue and just suffocating himself. It’s awful.’It was so unexpected because even though he was in his eighties, before this disease got ahold of him, he was still super mobile, healthy, and no real other ailments that he was struggling with.’And then this disease just ate away his brain and just everything collapsed from within. ‘It just goes to show, I’ve got two grandparents, one’s physically fit, the other one’s mentally so sharp and yet they were both snatched away by this disease. So it’s really terrifying to be that close to it. ‘My alignment with the charity now is because of those two, but it’s also left this fear in myself because if Leo ever has to feed me in a chair and I don’t recognise my own son, that’s like the worst nightmare possible.’According to Alzheimer’s Society, in the vast majority of cases (more than 99 in 100), Alzheimer’s disease is not inherited.The most important risk factor for Alzheimer’s disease is age. Because Alzheimer’s disease is so common in people in their late 70s and 80s, having a parent or grandparent with Alzheimer’s disease at this age does not change your risk compared to the rest of the population. However, if somebody has developed Alzheimer’s disease at an earlier age (for example, less than 60 years-old) there is a greater chance that it may be a type of Alzheimer’s disease that can be passed on. Ryan also discussed the dynamic of his young son Leo meeting with his great grandma to help other families torn with the decision. Ryan, who shares son Leo, four, with his fiancé Louise Thompson, is raising £25,000 for Alzheimer’s Society ahead of the gruelling challenge next month (Louise, Leo and Christine pictured three years ago) The fitness fanatic has shared his fears over one day inheriting the disease after two of his grandparents were diagnosed (Ryan, Louise and Leo pictured)He said: ‘Leo was just one years old, he sat on her knee for a photo. So Grandma has met Leo, thankfully. I don’t suppose either one of them will remember it, but at least they’ve had that moment, and we got our photo of them.’Leo is now four and a half, five in November, and actually, he’s now, like, so aware and so inquisitive, I just think he would be almost too confused by it. ‘I think if he was a little bit smaller, he would probably bring loads of innocence and joy to the room, and, arguably, it might help, but I just think now he would probably ask too many questions that I probably couldn’t answer.’He’s too young to understand, which is really sad, but at least they’ve met.’Ahead of his 26.2 miles run, Ryan said: ‘Fitness has always been quite therapeutic to me in that way. ‘If I’m truthful, I’ve never really loved running, but what running does do is that it give you a chance to think and ruminate and replay things in your mind.’WHAT IS DEMENTIA? Dementia is an umbrella term used to describe a range of progressive neurological disorders, that is, conditions affecting the brain.There are many different types of dementia, of which Alzheimer’s disease is the most common.Some people may have a combination of types of dementia.Regardless of which type is diagnosed, each person will experience their dementia in their own unique way.Dementia is a global concern but it is most often seen in wealthier countries, where people are likely to live into very old age.HOW MANY PEOPLE ARE AFFECTED?The Alzheimer’s Society reports there are more than 1million people living with dementia in the UK today, of which more than 500,000 have Alzheimer’s.It is estimated that the number of people living with dementia in the UK by 2040 will rise to more than 1.4million. As a person’s age increases, so does the risk of them developing dementia.Rates of diagnosis are improving but many people with dementia are thought to still be undiagnosed.IS THERE A CURE?Currently there is no cure for dementia. But new drugs can slow down its progression and the earlier it is spotted the more effective treatments are.Source: Alzheimer’s Society