Urinary iodine and serum 25-hydroxyvitamin D are associated with depression in adolescents

Purpose: To determine whether depressive disorder (DD) in adolescents is associated with the levels of serum 25-hydroxyvitamin D {25(OH)D} and urinary iodine. Methods: A total of 270 adolescent participants from 8 to 16 years old were enrolled in this study (male, n = 125; female, n = 145). Of these, 160 paticipants (male, n = 75; female, n = 85) were diagnosed with DD and 110 paticipants (male, n = 50; female, n = 60) were non-DD. Urinary iodine level, serum 25(OH)D level, and thyroid function were measured and adjusted for sex, age, body mass index, and disease progression. Vitamin D (25(OH)D) < 15 ng/mL was considered as VD deficiency, and iodine <100 μg/L was viewed as iodine deficiency. Mean VD and iodine levels were compared between DD and control groups. Results: DD patients had lower concentrations of 25(OH)D 3 (p < 0.005) and urinary iodine (p < 0.05) than non-DD control, in both male and female cohorts. However, serum 25(OH)D2 concentration did not significantly correlate with depressive symptoms. Conclusion: Adolescents with DD have markedly lower serum 25(OH)D concentrations and urinary iodine levels than control patients. This relationship is positively associated with disease progression, suggesting possible nutritional intervention measures for neuroprotection. Keywords: 25-Hydroxyvitamin D, Iodine, Adolescence, Depression