The problem with that claim is that you have to go back decades, where general quality of life was different, life expectancy was lower and the causes of death were different - or harder to assess. as this chart shows, average life expectancy has gone up from 50 to 75 in the past 50 years: https://en.wikipedia.org/wiki/Life_expectancy#/media/File:Li..., while this page (http://www.fauxpress.com/kimball/med/heart/h2/coronaryd.htm) indicates most heart disease only starts to show up after the age of 50.

So yeah, a bit hard to assess combined with higher life expectancy. Not impossible though, I'm sure there's good research out there.