Meta-analyses have shown that adult depression is associated with osteoporosis and lower bone mineral density (BMD). Smoking also has a negative impact on bone health, with adult smokers having lower BMD compared to nonsmokers, likely increasing lifetime fracture risk by as much as 31 percent.
Depression and anxiety increase in adolescence, particularly in girls, and smoking and alcohol use are often initiated at this time. Both depression and substance use often become chronic after adolescence. There is however a dearth of information on whether these factors affect bone accrual in adolescence.
Investigators from the Cincinnati Children's Hospital, University of Cincinnati College of Medicine, and The Pennsylvania State University recruited 262 healthy girls between 11 and 19 years from a teen health clinic in a large children's hospital and its surrounding community to represent typically developing adolescents and enrolled them in four age cohorts (11, 13, 15, and 17 years). The goal was to have each age cohort reflect the number of smokers proportional to national statistics. The girls each attended three annual onsite visits. Phone interviews were conducted at three-month intervals between annual visits.
Bone accrual trajectories from ages 11 to 19 were estimated for total-body bone mineral content (TB BMC) and lumbar spine and total hip bone mineral density (BMD).
Investigators found that while smokers entered adolescence with equivalent levels of lumbar spine and total hip BMD, overall BMD accrual across adolescence was significantly lower as smoking frequency increased. Depressive symptoms showed a slightly different pattern. Girls with higher levels of symptoms had significantly lower lumbar spine BMD consistently across adolescence. There also was no association between alcohol use or anxiety symptoms or their interactions with age on any bone measure.
"Adolescence is a crucial period of development that lays the foundation for women's health across the lifespan," said lead investigator Lorah D. Dorn, PhD, of Cincinnati Children's Hospital Medical Center and University of Cincinnati College of Medicine, Department of Pediatrics, Cincinnati, Ohio.
"As much bone is accrued in the two years surrounding menarche as is lost in the last four decades of life," she added.
The study has been published in the Journal of Adolescent Health.