I read somewhere that there is a decent statistical chance that Hillary or Trump can died before they finish their first term.
That depends. Statistically, we are way overdue for an unfinished presidential term. The last one was Nixon in 1974. And if you only count presidential deaths you have to go all the way back to JFK in 1963. It's been 42 years since an unfinished term; 53 since a presidential death in office. The only time we have ever gone so long is when the country was born: from George Washington's inauguration in 1789 it was 52 years before a president died in office (William Henry Harrison, a month after taking the oath). After that there were unfinished terms about every 20 years (20.55 to be exact) — 1841, 1850, 1865, 1881, 1901, 1921, 1945, 1963, and 1974. In fact, for a while every president elected in a year ending in "0" died in office. Ronald Reagan broke that trend.
But...
These types of statistics are not predictive. There is no better chance that a president elected in 2016 will die in office (or otherwise not complete their term) as any other president based on past patterns. It's just like flipping a coin — even if you get heads a thousand times in a row, on the next flip your odds are still 50/50.
Now, Clinton and Trump happen to be two of the oldest nominees ever chosen. If elected, Donald Trump would be the oldest president in history; Hillary Clinton would be the second-oldest. So based on that alone, there is a greater statistical likelihood of death or illness, simply because older people get sick and die more often than younger people. But that would be true of any older nominee (John McCain, for example), it's not unique to Trump and Hillary.
