Areal bone density in young females with different physical activity patterns: relationships with plasma leptin and...

The aim of this study was to find possible relationships between plasma leptin and bone mineral density (BMD) in weight bearing and non-weight bearing sites in young females with different physical activities and body composition parameters.

In 33 strength-trained, 32 endurance-trained, 41 sedentary normal weight and 23 sedentary overweight females, fasting plasma leptin and BMD of the total body, antero-posterior lumbar spine L2-L4, dominant arm distal radius and femoral neck were measured.

Endurance-trained females had lower values in L2-L4 when compared to strength-trained (P<0.01) and overweight (P<0.01) females. Normal weight sedentary females had lower (P<0.01) BMDs in sites L2-L4, femoral neck and total BMD when compared to strength-trained females. Overweight sedentary females had higher BMD values in sites L2-L4 (P<0.01) and total BMDs (P<0.05) when compared to normal weight sedentary females. No significant relationships (P>0.05) were found between plasma leptin and any measured BMD parameters in strength-trained and overweight sedentary females. In endurance-trained and normal weight sedentary females, leptin was correlated only with L2-L4 (r=0.461 and r=0.456, respectively). In normal weight sedentary females, distal radius BMD correlated significantly with leptin concentration (r=0.388).

Our findings indicate that plasma leptin concentrations, as a rule, are not directly related to areal BMD in young females. However, only in endurance-trained and normal weight sedentary groups, in L2-L4 sites and also in normal weight sedentary group at distal radius, leptin concentrations are related to areal BMD via body fat mass.