Nicotine-laden e-cigarettes raise a user's risk of blood clots, damage small blood vessels and can also raise heart rate and blood pressure, a new study finds.

The effects are similar to those caused by traditional cigarettes, and raise the concern that long-term vaping could help cause heart attacks or strokes, the Swedish research team warned. "Our results suggest that using e-cigarettes that contain nicotine have similar impacts on the body as smoking traditional cigarettes," said study author Gustaf Lyytinen, a clinician at Helsingborg Hospital and researcher at the Karolinska Institute in Stockholm.