Mt Baker Vapor who are a popular eJuice vendor in the US put the following statement out today:

"Here at Mt Baker Vapor we have been following the recent studies about Cinnamon flavors very closely. At this time we do not have enough information to make a statement on the issue either way. At this time we have decided to remove any flavors that contain Cinnamon while we continue our research. Our biggest concern is our customers and their health. We will keep you all posted on this situation. Please feel free to contact at support@mtbakervapor.com if you have any comments, questions or concerns."

They pulled their cinnamon juices because of this study:
http://www.sciencedirect.com/science...87233313002610

It seems that cinnamon flavours may become a thing of the past, especially if further studies come out to corroborate what this study has shown.