Associations of major depressive disorder and related clinical characteristics with 25-hydroxyvitamin D levels in middle-aged adults

ABSTRACT

Background: Vitamin D deficiency has been suggested to contribute to the onset of depression, but published results are inconsistent. The aims of this study were 1) to compare serum 25-hydroxyvitamin D (25(OH)D) levels in patients with depression and non-depressed controls and 2) to examine whether distinct subtypes and symptom severity of depression may vary in their association with 25(OH)D.

Methods: The study involved cross-sectional data of n=1169 participants from the BiDirect Study (n=639 patients with clinically diagnosed major depressive disorder (MDD), n=530 controls). Serum 25(OH)D was measured via LS-MS/MS. We performed analysis of covariance to evaluate adjusted means of 25(OH)D levels and multinomial logistic regression to assess the association of depression and its clinical characteristics, namely distinct subtypes and symptom severity, with 25(OH)D status (adjusted for age, sex, education, season of blood sample collection, and lifestyle factors).

Results: In total, 45.0% of the participants had adequate 25(OH)D levels (≥20 ng/ml), whereas 24.9% had a deficiency (<12 ng/ml). Patients with MDD had lower 25(OH)D levels than controls (16.7 vs. 19.6 ng/ml, p<0.001). Patients with atypical depression had the lowest levels (14.6 ng/ml). Symptom severity was inversely related to 25(OH)D. Moreover, patients with MDD had a more than 2-times higher odds of 25(OH)D deficiency than controls. Atypical depression showed the highest odds of deficiency.

Conclusions: The results support that patients with depression have lower 25(OH)D concentrations than non-depressed individuals. Distinct subtypes, particularly the atypical subtype, may play a special role in this context. Therefore, depression heterogeneity should be considered in future research.

KEYWORDS:

• vitamin D
• 25-hydroxyvitamin D
• major depressive disorder
• depression subtypes
• melancholic depression
• atypical depression
• severity of depressive symptoms
• depression heterogeneity

Acknowledgements

We would like to thank all participants of the BiDirect Study for their interest and engagement. This study could not have been realized without the support of many co-workers in the study center as well as in the following psychiatric departments and out-patient institutions: Dept. of Psychiatry and Psychotherapy, University Hospital Münster; Dept. of Psychosomatics and Psychotherapy, University Hospital Münster; St. Rochus-Hospital, Telgte; Alexianer Krankenhaus, Münster-Amelsbüren; LWL Klinik, Münster; Klinik am Schlossgarten, Dülmen; as well as the APV, IPP, and DGVT in Münster. We would also like to thank our team of study nurses and data managers for their excellent work and continuous commitment.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Ethical standards

The authors assert that all procedures contributing to this work comply with the ethical standards of the relevant national and institutional committees on human experimentation and with the Helsinki Declaration of 1975, as revised in 2008.

Additional information

Funding

The BiDirect Study is funded by the German Federal Ministry of Education and Research (Bundesministerium für Bildung und Forschung, BMBF) under grant numbers 01ER0816 and 01ER1506. The funding source had no role in study design, in the collection, analysis, and interpretation of data, in the writing of the report, and in the decision to submit the article for publication.

Notes on contributors

Corinna Köhnke

Corinna Köhnke is a post-doctoral researcher at the Institute of Epidemiology and Social Medicine at the University of Münster.

Markus Herrmann

Markus Herrmann is a professor at the Medical University of Graz and the director of the Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz.

Klaus Berger

Klaus Berge is a professor at the University of Münster and director of the Institute of Epidemiology and Social Medicine at the University of Münster.