Leading a country comes with extraordinary privileges but also, apparently, a price: new research suggests that heads of state age faster than normal and that the stress of the job may shave almost three years off their life expectancy. Doctors analyzed how long presidents and prime ministers in 17 countries - including Britain, Canada, France, Germany and the U.S. - survived after leaving office, compared to the losing candidates. They also observed the number of years that heads of state lived versus what was expected for someone of the same age and gender. After considering the fates of 279 heads...