Hmmmmm, it's just odd that one never heard about it till a few years ago and now it's everywhere.
How ever did our grandparents survive?
They weren't obese. As mnem wrote, obesity complicates the condition significantly.
Of course, they had other things that killed them, too, things we are getting better at delaying, like workplace accidents and long-time exposure to toxins, leaded fuel, oil-fired furnaces, coal-burning railways, smoking related issues, drinking. This means that natural attrition has to keep up with medicine, and invent new things to kill us with, lest we become too many. What of course happens is that all those things that kill people nowadays (like effects of apneas) didn't stand a chance before, because they were too slow. Or weren't so frequent, because they're overconsumption (related) diseases.
In the end, entropy and DNA corruption (cancer) will kill us all, if nothing else comes first.