High blood concentrations of vitamin D may be linked to a reduced risk of developing age-related macular degeneration in postmenopausal women, according to a new US study.
In the observational study, blood levels of vitamin D – measured as 25(OH)D, the non-active “storage” form of the vitamin – were analyzed in 1,313 women aged between 50 and 79 (1) to determine a potential association with the risk of developing age-related macular degeneration (AMD). For the full spectrum of age, the study found no relationship between vitamin D and any form of AMD. However, when the researchers limited their analysis to women younger than 75, they found that higher 25(OH)D levels were associated with a significant decreased risk of early AMD. The highest average intake of vitamin D from food and dietary supplements (15.1 micrograms per day) was associated with a 59 percent decrease in the risk of developing early AMD, compared to the lowest average intake (7.9 micrograms per day).
The researchers noted that this association was not explained by dietary intake of lutein plus zeaxanthin or polyunsaturated fatty acids. Commenting on the potential mechanism, the scientists said that inflammation is reported to be involved in the development of AMD, a degenerative retinal disease that causes central vision loss and leaves only peripheral vision. As vitamin D has anti-inflammatory effect, it may suppress the cascade of destructive inflammation that occurs at the level of the retinal pigment epithelium in early stages of AMD. They added that more studies are needed to verify this association and better understand the potential interaction between vitamin D status and genetic and lifestyle factors with respect to risk of early AMD.