Leptin levels were negatively associated with lumbar spine bone mineral content in children with overweight or obesity.

Adipokines seem to play a role in bone morphogenesis, although this also depends on the mechanical forces applied to the skeleton. The aim was to assess the relationships of resting leptin and adiponectin with bone parameters and whether high muscular fitness levels affect these relationships in children with overweight or obesity. This cross-sectional study took part from 2014 to 2016 in Granada, Spain. Participants were recruited from University Hospitals, and we also used advertisements in local media and school contacts in the city. Adipokines were analysed in plasma. Muscular fitness was assessed by one repetition maximum in bench and leg press tests. Dual-energy X-ray absorptiometry was used to measure bone parameters. We included 84 children (10.0 ± 1.2y; 63% boys) in this analysis. Leptin was negatively associated with lumbar spine bone mineral content (β = -0.162, p = 0.053). No significant interaction was found for muscular fitness. Simple slope estimates suggested that children performing more than 133.3 kg in leg press test ameliorated the negative association between leptin and lumbar spine bone mineral content. Leptin levels were negatively associated with lumbar spine bone mineral content in children with overweight or obesity. A high muscular fitness at the lower body could counteract this association