Will I die while cycling to work?

What's the probability of dying early from obesity, diabetes or heart disease should you not cycle to work but sit in a car/bus/train?

Bloody high. I'd make something up off the top of my head and say around 35%

Agreed, no doubt that I'm much better off cycling to work than not. Although 0.5% is low, I'd expected much lower. I don't really know why.