The association of vitamin D deficiency with depressive disorders in patients with eating disorders: a cross-sectional study

Vitamin D deficiency and depressive disorders are both common in patients with eating disorders (EDs). However, the association between vitamin D status and current depressive disorder (CDD) in EDs populations remains insufficiently explored. We conducted a cross-sectional study including 481 outpatients with EDs assessed at a specialized eating-disorders unit in Montpellier, France. Psychiatric diagnoses were established using the Mini-International Neuropsychiatric Interview (M.I.N.I.). Eating-disorder severity was assessed with the Eating Disorder Examination Questionnaire (EDE-Q). Serum 25-hydroxyvitamin D levels were measured as part of routine clinical assessment, and vitamin D deficiency was defined as < 20 ng/mL. Odds ratios (ORs) were estimated using logistic regression. Vitamin D deficiency was significantly associated with higher odds of CDD (OR 1.98, 95% CI 1.20–3.28; p = 0.008). This association persisted after adjustment for EDs severity, psychiatric comorbidities, and season of assessment. No significant interactions were found between vitamin D deficiency and eating-disorder subtype, EDE-Q score, or season. Vitamin D deficiency was associated with the presence of a current depressive disorder in patients with eating disorders, independently of EDs subtype, severity, and seasonality. These findings support the clinical relevance of assessing vitamin D status in patients with EDs presenting with depressive symptoms. Longitudinal studies are needed to clarify the direction and clinical implications of this association. People with eating disorders often have low vitamin D levels, and depression is also common in this group. We studied 481 outpatients seen in a specialist eating disorder service in Montpellier, France, to find out whether vitamin D deficiency was more frequent in those who also had a current depressive disorder. Vitamin D deficiency was defined as a blood level below 20 ng/mL. We found that patients with vitamin D deficiency were almost twice as likely to have a current depressive disorder as those without deficiency. This relationship remained after taking into account eating disorder severity, other psychiatric conditions, and the season of assessment. It was also similar across different eating disorder subtypes. Because this was a cross-sectional study, we cannot determine whether low vitamin D contributes to depression, whether depression contributes to low vitamin D, or whether other factors influence both. Still, our findings support checking vitamin D status in patients with eating disorders who present with depressive symptoms.