I noticed a mortality study that illustrates some of the common wisdom regarding the common diseases of aging:
The remaining lifetime risk of cancer at age 40 was 45.1% and at age 90 was 9.6%. The remaining lifetime risk of major cardiovascular disease at age 40 was 34.8% and at age 90 was 16.7%.
The remaining lifetime risk of both diseases approached a plateau in the 10th decade. This may be due to decreased detection of disease and reporting of symptoms and increased resistance to disease in those who survive to old age.
The older a person becomes - or rather, the more capable a person is of achieving longevity - the less likely he or she is to suffer from the major diseases of aging. As the authors point out, however, it's a challenge to build reliable data:
The measurement and interpretation of the incidence of disease in advanced age is complex. Lower incidence in late life may reflect decreased screening and medical surveillance rather than decreased risk. ... This cohort of health conscious doctors has several advantages for studying the incidence of disease in men of advanced age, as it has a large proportion of participants surviving to age 90 and beyond, as well as a higher level of screening for disease and diagnosis than in a general population.
This and other collections of data on mortality risk consistantly show that incidence of cancer and cardiovascular disease is lower for those who live longer. Other research shows that living longer within the present state of medical science is a matter of making consistently sensible choices in life for most of us - not a matter of good genes to any great degree. Join the dots: all that exercise and good diet really does make a difference in the long term.
Now if you have a good few decades left before getting to the point at which you have to start worrying in earnest about your heart and runaway cells killing you from the inside, it's probably the case that the future trajectory of your life will be far more determined by progress in medical science than living well. Absent progress, your life will look much like that of your parents. With exceptional progress, the sky is the limit - aging itself might be defeated before you reach the point at which it will kill you. So while you're on the execise machine, or pondering a good diet, spare some thought for how you can support the future of medical research as well. There is where the real difference lies.