Maybe of interest here?
http://www.bbc.co.uk/news/uk-wales-30309335

"Three times as many children have tried e-cigarettes as have smoked tobacco, according to official figures.

It has reinforced concerns that using the devices could become a "gateway" to smoking cigarettes.
The study found 6% of 10 to 11-year-olds in Wales said they had used e-cigarettes, compared to 2% who had smoked tobacco."

There's plenty more in the news article, including a link to the full Childhood Exposure to Tobacco Smoke (CHETS) report.