Term of Award

Fall 2022

Degree Name

Doctor of Public Health in Epidemiology (Dr.P.H.)

Document Type and Release Option

Dissertation (restricted to Georgia Southern)

Copyright Statement / License for Reuse

Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.


Department of Epidemiology (COPH)

Committee Chair

Kelly Sullivan

Committee Member 1

Hani Samawi

Committee Member 2

Logan Cowan


Depression remains a problem with high prevalence, particularly in many parts of the United States, despite the availability of drugs and non-pharmacological therapy. Although common demographic risk factors for depression have been investigated, the association between dietary factors and depression prevalence and severity have largely been unexplored, especially the effects of vitamins including Vitamin C and complex compounds like caffeine and their interactions on depression prevalence and symptoms, especially in the context of a large representative sample. Several studies have been conducted to evaluate the common pharmacokinetic parameters (absorption, metabolism, distribution, and excretion) and to evaluate the effects that vitamin interactions may have, most of which are lab-based. Additionally, several observational studies have been conducted in order to determine the effects of individual vitamins on depression. These studies have largely conflicting results regarding the effects and magnitude of vitamin effects without any studies specifically evaluating the effect of vitamin interactions on depression and have limited generalizability. In order to evaluate the effects of individual vitamins on depression as well as the effects of its interactions on depression, the present study employed data collected via National Health and Nutrition Examination Survey (NHANES). In addition to analyzing the effects of individual dietary components and demographic factors, a total Composite Score was derived that included commonly consumed dietary components used in other contexts in previously conducted studies. Data from the NHANES data corresponding to the years between 2005-2014 contained the relevant demographic, vitamin, and depression information for the analysis. Based on the results of the study, lipophilic vitamins, Vitamin C and the Composite Score had a negative association with depression prevalence, whereas the bivariate combination of these three nutritive components had a positive association with depression prevalence, which were statistically and clinically significant if taken at the daily values of NHANES participants; these effects are consistent with plausible biological mechanisms of action, including intermolecular interactions as well as interactions with receptors.

Research Data and Supplementary Material


Available for download on Sunday, October 31, 2027