Influence of Mediterranean Diet Adherence and Physical Activity on Bone Health in Celiac Children on a Gluten-Free Diet

We aimed to assess the influence of the Mediterranean Diet adherence and physical activity (PA) on body composition, with a particular focus on bone health, in young patients with celiac disease (CD). The CD group (n = 59) included children with CD with a long (>18 months, n = 41) or recent (<18 months, n = 18) adherence to a gluten-free diet (GFD). The non-celiac group (n = 40) included non-celiac children. After adjusting for potential confounders, the CD group showed lower body weight (p = 0.034), lean mass (p = 0.003), bone mineral content (p = 0.006), and bone Z-score (p = 0.036) than non-celiac children, even when the model was further adjusted for adherence to a GFD for at least 18 months. Among CD children, spending greater time in vigorous physical activity was associated with higher lean mass (p = 0.020) and bone mineral density with evidence of statistical significance (p = 0.078) regardless of the time they followed a GFD. In addition, a greater Mediterranean Diet adherence was associated with a higher bone Z-score (p = 0.020). Moreover, lean mass was strongly associated with bone mineral density and independently explained 12% of its variability (p < 0.001). These findings suggest the importance of correctly monitoring lifestyle in children with CD regarding dietary habits and PA levels to improve lean mass and, consequently, bone quality in this population.