Vitamin D deficiency and older age tied to higher risk of depression

Worldwide, depression is one of the most common mental disorders that has become a major public health concern and one of the leading causes of the global disease burden. Its occurrence risk is associated with vitamin D deficiency and may also increase with age, while there is a close relation of serum vitamin D levels with age.

The existing studies primarily focused on the relationship between vitamin D and depression, or the relationship between depression and age, and they lacked analysis and comparison of the relationship between these three predictors in the same sample. Additionally, in these predictors, there is also a lack of large-sample epidemiological surveys. Therefore, it is particularly requisite to conduct a reliable cross-sectional analysis of large samples in a representative population.

Considering the above, Hongfei Mo, Zhengzhou University, Zhengzhou, Henan, P.R. China, and colleagues aimed to evaluate whether vitamin D and age are associated with depression after adjustment for each other.

For this purpose, data were obtained from NHANES 2013–2018, including depression level, demographic characteristics, physical activity, vitamin D level, and body measures. The study included 15,156 adults aged 20 years or older (mean age 49.81 ± 17.67 years, 7855 females). PHQ-9 was used for screening depression. Vitamin D deficiency was a serum vitamin D level below 30nmol/L. The association between vitamin D, age, and depression was analyzed using binary logistic regression models.

The authors reported the following findings:

• Vitamin D levels were negatively associated with depression.
• Vitamin D had a significant effect on depression (OR = 0.776), but the effect remained significant after adjusting for confounding variables (OR = 0.761).
• Age was positively associated with depression and had a significant effect on depression (OR = 1.079), the effect remained significant after adjusting for confounding variables (OR = 1.092).
• Age and vitamin D levels were positively correlated, and older age had a significant effect on vitamin D levels (OR = 1.526), the effect remained significant after adjusting for confounding variables (OR = 1.371).
• The prevalence of depression was higher in females (29.43%) than in males (21.52%), and the difference was statistically significant.

"The study results indicate that both vitamin D deficiency and older age are both associated with increased depression risk, even though vitamin D deficiency was more prevalent in the younger population of our sample," the researchers wrote.

"These conclusions provide evidence for the view that “younger people are more likely to be vitamin D deficient” and provide the scientific basis for early prevention of depression," they concluded.

Reference:

Mo, H., Zhang, J., Huo, C. et al. The association of vitamin D deficiency, age and depression in US adults: a cross-sectional analysis. BMC Psychiatry 23, 534 (2023). https://doi.org/10.1186/s12888-023-04685-0