They do not. It was suggested that ones with flavour containing diacetyl could cause popcorn lung. However, cigarettes contain a lot more diacetyl, and popcorn lung is not one of the many health risks of smoking. There is some anecdotal connection between diacetyl and popcorn lung, but far from a scientific consensus.

Ouch… Personal phone number exposed on Google Play? Not good. If there is not a cheap and easy way for me to get a second phone number I guess I am out. Have seen it coming for a while, Google Play is no longer a place to be for indie devs.