Endocrine Abstracts

Background: Higher body weight is associated with greater bone mineral density (BMD). Lean mass (LM) is positively related with bone parameters in adolescence. However, a number of controversial studies have suggested that fat mass (FM) has beneficial effect or has detrimental effect on BMD in adolescence. These contradictory results of FM on bone parameters might be developed by the non-linear relationship in the adolescent population.

Objective: We evaluated the effect of FM on BMD in Korean adolescent teenagers according to gender and menarcheal status in female.

Methods: We analyzed the data of 2,060 Korean adolescent teenagers (male=1,114; female=946) aged 10 to 19 years from the Korea National Health and Nutrition Examination Survey (2008–2011).The whole body bone mineral content (BMC), bone area (BA), and soft tissue composition (LM and FM) excluding head (total body less head) were measured by dual-energy X-ray absorptiometry. Bone parameters were compared among groups according to age-specific quartiles of total body FM. The effect of FM on BMD was evaluated by multiple regression models (age, menarcheal status, LM, and FM) with second-order polynomial terms for FM.

Results: Bone parameters (BMC, BA, and BMD) were greater in the group of higher quartiles of FM than that of lower quartiles. In a multiple regression result, FM was negatively related to BMD in male adolescents. Furthermore, in a model with second-order polynomial terms for FM, it was in an inverted U-shaped curvilinear relationship with BMD in female adolescents, especially in premenarcheal state.

Conclusions: Our study shows that the relationship between BMD and FM is depended on gender and menarcheal state. The relationship is an inverted U-shaped curve in Korean premenarcheal adolescent teenagers and negative in male adolescents. FM may be beneficial in premenarcheal adolescent. However, FM might have a detrimental effect on BMD in adolescent period with excess FM.