Since when are cancer and heart disease relatively new? They've been around for as long as people have, just most people didn't live long enough to get them for other reasons.
By "new" I mean that only relatively recently in human history (in the last ~100 years) have people been able to live long enough that these become health problems of concern. Before the 20th century, most folks just got sick as a result of an infection of some kind and died.
All I am saying is that there will be other new problems that are uncovered as we continue to extend human life-span.
