The Association With Vitamin D and Depression in US Adults

Objectives: There has been limited data regarding the relationship between Vitamin D and depression. The objective of this study was to study the association between serum vitamin D levels and depressive symptoms, as well as vitamin D intake and clinical depression in US adults. Methods: Data from a nationally representative sample of 4,641 adults who participated in the 2017-2018 NHANES survey was analyzed. During the NHANES, adults participated in a physical examination, complete with blood draw. Dietary intake data was obtained using 24-hour recall. Serum vitamin D was collected for study participants during the MEC exam using the CDC method of high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) for the quantitative detection of 25-hydroxyvitamin D. For the present analysis, serum Vitamin D levels are presented as 25-hydroxyvitamin D2 + D3 (nmol/L). Depression was assessed using the PHQ-9. All data were analyzed using SAS 9.4 survey procedures to account for the unequal sampling probability and complex survey design of the NHANES. All models are energy-adjusted and adjusted for age, sex, race/ethnicity, educational attainment, and household income. Results: In this sample of US adults, there was a significant negative linear relationship between serum Vitamin D and reported depressive symptoms (p=0.03). Additionally, higher levels of serum vitamin D levels were associated with better physical functioning. When evaluating Vitamin D intake, individuals with clinical depression had significantly lower intake of Vitamin D from food sources (4.3 vs 3.3 mcg, p=0.004) than those without depression. Conclusions: These results demonstrate an association between serum vitamin D level, depression, and physical functioning in adults. Public health messaging that encourages intake of Vitamin D-rich foods may be an important dietary strategy for supporting mental health.