Metabolic syndrome reduces bone mineral density in overweight adolescents

Growing concern has focused on the occurrence of metabolic syndrome (MetS) and its effects on bone mass. There is little information available in the literature concerning the relationship between MetS and BMD in adolescents. The aim of this study was to evaluate the effects of MetS and its components on bone mineral density (BMD) in overweight adolescent boys and girls. This cross-sectional study assessed 271 overweight adolescents with or without MetS (age 10 to 16years). Anthropometric and biochemical tests were performed. Lumbar spine, proximal femur and total and subtotal body BMD values were obtained by bone densitometry with dual-energy X-ray absorptiometry. MetS was observed in 14% of the adolescents. Overweight adolescents of both genders who were positive for MetS presented with significant decreases in BMD (g/cm(2)/kg bodyweight) at all sites evaluated (p<0.01). Female adolescents with large waist circumference, low HDLc, hypertriglyceridemia and high blood pressure showed significant reductions in BMD at all sites evaluated (p<0.01) and, with the exception of increased triglycerides (which had no effect on BMD, p>0.05), the same pattern was observed in male adolescents. Linear regression analyses revealed that waist circumference was negatively correlated with BMD in both genders and that triglycerides were negatively correlated with BMD only in female adolescents. Our results suggest that overweight adolescents with MetS have lower BMD than adolescents without MetS. Among all MetS components measured, increased waist circumference had the strongest relationship with reductions in BMD.