Lorah Dorn of Cincinnati Children's Hospital and colleagues analyzed data on 262 healthy girls.
The researchers found girls who entered adolescence had about the same bone density whether or not they smoked, but the girls who smoked more had gained less bone at the end of adolescence.
Dorn said that's especially important because the teen years are crucial for building bone for adulthood.
"You're really laying what we think is an important foundation for bone health across the lifespan of a woman," Dorn said in a statement.
The study was published in the Journal of Adolescent Health.