Bone Abstracts

Objective: Since depressive symptoms, which have been related to low bone quality in adulthood, may also be associated with suboptimal bone mineral accrual, we aim at quantify the association between depressive symptoms and bone mineral density (BMD) throughout adolescence.

Methods: We analysed prospective data from 969 adolescents (56.2% girls) from a population-based cohort of urban adolescents, born in 1990, evaluated during the 2003/2004 and 2007/2008 school years in public and private schools of Porto (EPITeen). In both evaluations, at 13 and 17 years of age, the severity of depressive symptoms in the previous 2 weeks was evaluated by self-report using the Beck Depression Inventory-II (BDI-II). Bone mineral density (g/cm²) was measured at the non-dominant forearm by dual-energy X-ray absorptiometry (DXA) using a Lunar Peripheral Instantaneous X-ray Imager (PIXI) device. In order to estimate the cross-sectional and prospective associations between depressive symptoms and BMD during adolescence, linear regression coefficients (β) and 95% CIs crude and adjusted for BMI, age at menarche, smoking, and sports practice were estimated.

Results: In girls, mean (S.D.) forearm BMD was 0.360 (0.057) at 13 years old and changed 0.024 mg/cm² per year, while in boys was 0.346 g/cm² (0.053) at 13 years of age and changed 0.035 mg/cm² per year. In girls, median (25th and 75th percentiles) BDI-II score remain the same at 13 and at 17 years old (6.0 (2.0; 10.0) and 6.0 (3.0; 11.0) respectively), while in boys BDI-II scores decreased from 13 to 17 years of age (3.0 (1.0; 6.0) and 2.0 (1.0; 6.0) respectively) and, comparing with girls, were lower in both evaluations. In both sexes, cross-sectional associations between depressive symptoms and BMD at 13 and 17 years old were not detected even after adjustment for major confounders. Similarly, there were no significant associations between depressive symptoms during adolescence and the annual BMD change from 13 to 17 years old.

Conclusion: Depressive symptoms were not associated with BMD accrual throughout adolescence. The mechanisms explaining the relationship between depression and BMD are not largely known and explored, but they may not be present at this period of life.