A study has revealed that nonsmoking adolescents who use e-cigarettes, smokeless tobacco or tobacco water pipe are more likely to start conventional smoking within a year. A group of researchers from US San Francisco analysed more than 10,000 adolescents, ages 12 to 17 using nationally-representative data to determine the estimate of alternative. The researchers concluded that youths who used e-cigarettes get mostly associated with conventional smoking within a year. The study also discovered that more than 90 percent smokers started smoking at the age of 18-years. The use of e-cigarettes has gained popularity in recent years and e-cigarettes, the most common form of tobacco used by youth.