Does stress cause U.S. Presidents to age faster and die younger?

Being the U.S. President is a stressful job — just look at how quickly our last few leaders have gone grey while in office. But is that stress enough to shorten their lifespans? A piece of research in this month's Journal of the American Medical Association answers that question definitively. » 12/07/11 8:34am 12/07/11 8:34am