The big yin has had cancer surgery and also has early onset Parkinsons disease, well he did appear on the show many times
http://www.bbc.co.uk/news/entertainment-arts-24106842
I would think the new next few years might be the best chance to see more guys on the list of Worlds Oldest since we are coming towards men who were born in a time where they were too young to fight in WW1 and too old for combat by the time WW2 comes around.