He's already been shot down a few times. Glutton for punishment?
The ultrafine particles that cigarettes (and e-cigarettes) deliver have substantial adverse effects on the cardiovascular system. (reference: Institute of Medicine. Secondhand Smoke Exposure and Cardiovascular Effects: Making
sense of the Evidence. 2009. Also see Barnoya J, Glantz S. Cardiovascular effects of secondhand smoke: nearly as large as smoking. Circulation 2005 May 24;111(20):2684-98 and Grana RL, Benowitz N, Glantz SA. E-cigarettes: a scientific review. Circulation 2014 May 13;129(19):1972-86. doi: 10.1161/CIRCULATIONAHA.114.007667.)
Response
The same studies were again cited in the second argument, with the addition of the latest review on e-cigarettes. However, this is a direct mis-presentation of evidence,
since there is not even a single study indicating that particles emitted from e-cigarettes represent a risk factor for cardiovascular disease.