Association Between Socioeconomic Status and Early Initiation of Smoking, Alcohol Drinking, and Sexual Behavior Among Korean Adolescents.

We analyzed data from the Korean Youth Risk Behavior Web-based Survey (N = 68 043), a nationally representative survey, to examine the association between early initiation of smoking, alcohol drinking, and sexual activity and socioeconomic determinants among adolescents. The prevalence rates of early initiation of smoking (i.e, starting at age 12 years or younger), alcohol drinking, and sexual activity were 4.