The Relationship of Vitamin D Status, Adherence to the Mediterranean Diet, and Physical Activity in Obese Children and Adolescents

Abstract

Vitamin D deficiency is associated with a range of chronic diseases, including childhood obesity. Prevalence of vitamin D deficiency in obese children and adolescents ranges from 6.5% to 57%. This cross-sectional study included 92 obese patients with body mass index z-score >2 and 39 subjects in the control group. Anthropometric and laboratory patient assessment were performed, including the fasting 25-hydroxyvitamin D (25(OH)D). Adherence to the Mediterranean diet was assessed by Mediterranean Diet Quality Index for children and adolescents (KIDMED index), while physical activity was evaluated by Physical Activity Questionnaire (PAQ). Serum levels of 25(OH)D were significantly lower in obese subjects compared to the control group (52.0 ± 17.93 vs. 64.09 ± 25.82 nmol/L, P = .003). The subgroup of obese patients with metabolic syndrome (MS) had significantly lower levels of serum vitamin D when compared to the subgroup of obese patients without MS and the control group (46.99 ± 17.11 vs. 54.58 ± 17.93 vs. 64.09 ± 25.82 nmol/L, P = .003). Obese patients with MS had lower PAQ score when compared to obese without MS and the control group (2.32 ± 0.55 vs. 2.49 ± 0.67 vs. 2.85 ± 0.63 nmol/L, P = .002), while no significant differences were observed in the KIDMED index (4.23 ± 1.81 vs. 4.21 ± 2.13 vs. 4.87 ± 2.29, P = .251), respectively. PAQ score was in positive correlation with serum levels of 25(OH)D (r = 0.305, P < .001). This study demonstrated that obese children and adolescents have significantly lower values of serum 25(OH)D. The positive correlation between vitamin D and PAQ score points to the importance of physical activity in the prevention of further cardiovascular complications and MS.