As Donald Trump and his allies attempt to raise dubious questions over Hillary Clinton's health, the Republican nominee has invited new scrutiny into his own medical history. Like Clinton, Trump has released minimal information, most notably in the form of a December 2015 letter of a few paragraphs from his personal physician, a gastroenterologist, that described his blood pressure and lab results as "astonishingly excellent" while suggesting a President Trump would be the "healthiest individual ever elected." Dr. Sanjay Gupta, CNN's chief medical correspondent, found much of that language surprising and, in some cases, almost comically lacking in objective data....