In girls, depression, anxiety, and smoking may inhibit bone development during the critical bone growth phase of adolescence, study findings suggest.

Failure to obtain maximal bone density during adolescence, when nearly 40 to 50 percent of bone mass or density is attained in girls, leaves "a deficit in the bone bank," Dr. Lorah D. Dorn told Reuters Health.

This may increase vulnerability to late life skeletal bone loss and brittleness known as osteoporosis, said Dorn of the University of Cincinnati College of Medicine in Ohio.

Because of the strong link between osteoporosis and depression and smoking in adults, Dorn and colleagues looked for similar associations among adolescents,

The researchers examined bone mineral density and bone mineral content — both indicators of bone growth and health — among 207 girls, who were 11, 13, 15, and 17 years old. They also obtained information on depression, anxiety, and smoking. About 47 percent of the girls had smoked, or daily smoked, tobacco products.

According to a report in Archives of Pediatric and Adolescent Medicine, the investigators observed a significant association between higher levels of depressive symptoms and lower total body bone mineral content after factoring for age, height, weight, maturation, race, and the interaction between age and race.

Dorn's team also associated high states of anxiety with lower total body bone mineral content, but only among white girls.

Girls who smoked daily had higher levels of depression and anxiety than girls who did not smoke, but bone health was similar between the two groups.

Further multiple analyses that factored for smoking status either enhanced or weakened associations with bone mass or bone density depending on the presence or absence of symptoms of depression and anxiety.

The complex associations identified in this study not only warrant further examination, but raise concern that depression, anxiety, and smoking potentially impact bone health during a crucial developmental period for adolescent girls, Dorn and colleagues conclude.