How common is it for anyone to retire before 24? Seems to me if you had to retire before 24, you were probably doing so because of a disability or illness. It seems logical that these people would die earlier.
Perhaps the study didn't adjust for people who left the workforce early due to health reasons? 24 seems very young. Why not look at what happens to people who retire between 40-55?
Since the upper age quoted for the study two lines above is "64", I presume the "24" is a typo.
OK, keep your eye on me. I retired when I was 46 and now I'm 59. If I quit posting you can assume it's because I'm dead. =:0