The easy social explanation for this is that people who vape are more likely to be around smoking anyways, and thus are far more likely to bum a cig off someone

The easy social explanation for this is that people who vape are more likely to be around smoking anyways, and thus are far more likely to bum a cig off someone in a party than your average 19 year old. The only clinical result you can pull from this is 'people who vape are more likely to smoke >1 cigarette a year', and the fact that they couldn't produce a more significant result with any sort of correlation tells you the paucity of the data.