A study in the BMJ shows that those who retire at age 55 have an almost 2 fold increased risk of dying in the subsequent 5 years relative to those who kept working. However, retiring at 60 neither increases nor decreases mortality compared to those who kept working until the mandatory retirment age of 65.
The study utilized records from Shell Oil about its employees. One could imagine some jobs at an oil company are bad for health due to exposure to various toxins, but if anything early retirment seemed to be the most detrimental for those classified as having low socioeconomic status.
Of course, the big confounder, acknowledged in the article, is that those in poor health probably retire early.
Th article claims:
there is a widespread perception that early retirement is associated with longer life expectancy and that retiring later leads to early death.
but this seems contrary to what most people I know believe, which is that many people who retire early just sit around waiting to die.
Personally, I hope to never retire, but am lucky in that I enjoy what I do.