Retire Earlier Die Earlier?

Surprisingly people seem to die earlier when they retire earlier (link below) and this seems especially true for blue collar workers. This weakens the argument that waiting longer to retire is very hard on the blue collar workers.
http://www.freakonomics.com/2012/05/17/retirement-kills-a-new-marketplace-podcast/

http://www.webmd.com/healthy-aging/news/20051020/early-retirement-early-death

http://www.medpagetoday.com/PrimaryCare/PreventiveCare/1980