Just how?

Well I'm assuming they don't die BECAUSE of the pants, they simply die while they're wearing them. Like getting shot while putting them on or something.

They probably fell whilst doing the my jeans won't pull up jump thingy hit their temple then died

http://www.mirror.co.uk/news/weird-news/man-dies-after-falling-over-223156

A friend of my friend was putting pants on and he fell down and broke his neck and died...

There is a 329% chance that I'm going to be one of those people eventually

That settles it. No more pants!

I'm thinking these people were probably standing on a balcony in their underwear, attempted to pull up their too tight jeans by jumping, realized they were the worst jumpers ever, fell off the balcony, and splat.

The keyword here is "while". Correlation is not causation.

It's them skinny jeans, i'm telling you. You wiggled, jumped, rolled, struggling to squish your fatty calves and thighs into those satanic pipes, it hurts, it hurts, your breathing labored, as your lower extremes' blood flow getting cut bit by bit, and you feel suffocated, nauseous and faint, and the next thing you remember you're knocking on heaven's door . But fashionably, of course.