Systematic ReviewHumann = 15 studies (9 on vitamin D and depression, 6 on vitamin D and testosterone)2023
Vitamin D, testosterone and depression in middle-aged and elderly men: a systematic review.
Plain-language summary
This review collected studies on vitamin D, testosterone and depression in middle-aged and older men. Nine of them measured depression against blood vitamin D and six measured testosterone against blood vitamin D. Across the cohort and cross-sectional studies it collected, low vitamin D went with more depression in older men, and higher vitamin D went with higher testosterone. The authors then propose, as a mechanism they did not test, that vitamin D could act on mood partly through testosterone. The review did not pool its studies into a single number and it did not test whether taking vitamin D changes mood, so it describes a pattern rather than an effect.
Key findings
- Vitamin D deficiency was linked to higher depression risk in older men.
- Men with higher vitamin D levels had higher testosterone.
- Testosterone may influence mood, and vitamin D could help protect against depression partly through its effect on testosterone.
How to analyze the study yourself
- Study type
- Systematic reviews compile existing studies to spot patterns, but they cannot prove cause and effect because they rely on the designs of the original studies, which here were mainly observational.
- Population
- Middle-aged and older men, in the studies the review collected.
- Funding
- Not reported
- Takeaway
- This review found that older men with low vitamin D had more depression, and that vitamin D and testosterone readings moved together. Because it only collected studies that measured these side by side, it cannot say that raising one raises the other. If your vitamin D has never been measured or you know it is low, it may be worth taking vitamin D, which is worth doing on its own terms whatever it does for mood.