Figure 1.
Trajectories of the likelihood of smoking initiation from birth through young adulthood among (a) US females and (b) US males: National Longitudinal Survey of Youth 1997.
Official websites use .gov
A
.gov website belongs to an official
government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely
connected to the .gov website. Share sensitive
information only on official, secure websites.