The increased popularity of e-cigarettes has reversed years of progress by educators, parents and doctors to turn young people away from nicotine, local health experts said Monday.

Fewer of middle school and high school age are smoking but use of e-cigarettes – which look like USB drives, are marketed as alternatives to smoking and contain nicotine, the addictive ingredient in tobacco – is rising, health officials said, and the harmful chemicals in the devices can affect heart and brain function.