The relationship between metabolic syndrome and bone mineral density in adolescents: analysis of the National Health and Nutrition Examination Survey

Objectives The purpose of this study was to observe the relationship between metabolic syndrome (MetS) and height (Ht) adjusted Z-scores for areal bone mineral density (aBMD) in adolescents. Methods A retrospective study was conducted on the United States adolescents aged 12-17 years. Data were extracted from the National Health and Nutrition Examination Survey (NHANES) 2011-2012, 2013-2014 and 2015-2016 cycles. Ht adjusted Z-scores for aBMD were calculated. Results A total of 969 adolescents (493 boys and 476 girls), aged 14.5 +/- 1.7 years were enrolled in this study. After control for age, gender, race, 25-hydroxyvitamin D [25(OH)D], and lean body mass index (LBMI) Z-score, adolescents with MetS had significantly lower levels of total body (less head) aBMD Ht-Z-adjusted Z-score than adolescents with one, two components of MetS and without component of MetS (p<0.05) and significantly lower levels of lumbar spine aBMD Ht-Z-adjusted Z-score than adolescents with one component of MetS and without component of MetS (p<0.05). There were significantly negative associations between total body (less head) aBMD Ht-Z-adjusted Z-score and waist circumference (WC) (beta=-0.027, p<0.001, R-2=0.057) and homeostasis model assessment insulin resistance (HOMA-IR) (beta=-0.225, p<0.001, R-2=0.016). There were significantly negative associations between lumbar spine aBMD Ht-Z-adjusted Z-score and WC (beta=-0.039, p<0.001, R-2=0.058) and HOMA-IR (beta=-0.251, p<0.001, R-2=0.008). Conclusion The present study demonstrates that MetS may have a negative effect on bone mineral density in adolescents. Abdominal obesity and insulin resistance play a major role on the decline of aBMD in adolescents.